Secure power specialist Dale Power Solutions has begun its 75th anniversary year with 75% order intake growth in the first six months of 2010.

As it looks back on a history which has taken it from humble beginnings to a global brand, renowned for its technical expertise and engineering excellence, Dale's range of new and existing products is seizing a bigger share of the market.

In all sectors - generator sets, uninterruptible power supply [UPS] battery products under the Erskine brand and in service and maintenance - Dale is enjoying international success. As part of the secure power division of TT electronics, it now employs 600 people worldwide with circa $120 million per annum.  

Each year Dale supplies more than 3,000 generator and battery-backed UPS worldwide and services more than 4,000 generator sets and UPS systems. Key customers are in sectors as diverse as oil and gas, industry, telecoms, hospitals, finance, tourism, leisure, and many more.

Against a backdrop of global recession, Dale is currently recruiting new apprentices, graduates and experienced staff to further strengthen its operation as it looks to meet future demand.

A new containerised generator set, the Dale Secure Power Series, is already selling well, just months since its introduction. Aimed primarily at the hire market, the range includes the Secure 1600 which sets new parameters for off-the-shelf containerised generating sets, packing step loads of up to 800kW into a 20ft container.

Dale is continuously seeking new markets across the world and expects continuing strong demand to come from the petrochemical industry, already a key sector for UPS and DC products. Dale has developed a new range of standard UPS systems alongside its Erskine branded industrial UPS products, designed specifically to work with its range of generator sets to provide an integrated solution and guarantee continuous power to its customers.
A new range of service products is also in the pipeline, an area of the marketplace where Dale's vast technical background and expertise - going back 75 years - has already made it a global name. Comprehensive service and maintenance, drawing on a team of more than 80 service personnel, helps key clients worldwide protect and prolong the life of their products.

The excellent start to 2010 has delighted managing director Tim Wilkins. He puts it down to a positive proactive workforce working very hard to meet customers' demands together with a strong product line-up and the development of new sales and service outlets, most recently in Swindon, Aberdeen and Sharjah.

"We have seen a very strong order intake for the first six months of 2010 and are pleased with the success of new and existing products," he said.

"We have strengthened our sales department and thanks to our new range of products and the strength of our existing generator, UPS and sales and maintenance products, we have captured a greater share of the market, both in the UK and export."

He puts the longevity and success of the brand down to excellent technical expertise, design capability, project management, installation and ongoing servicing.

"It continues to be our ability to discuss a customer's requirements with them and supply a tailored power solution that meets their needs exactly," he said.

"We operate lean enterprise 6 Sigma working practices and the Dale brand has become synonymous in the power industry with providing customers with an immediate, pro-active response and a perfect technical solution to their requirements."

"Whether it is off-shore oil and gas platforms, the stock exchange or a hospital operating theatre, our products and expertise are now an integral part of many large, blue-chip companies' risk and disaster recovery management plans."

Looking ahead, the company's business plan is to achieve continued growth, driven through increasing sales in existing and new markets, on a world-wide basis. It is also keeping an eye on the future and where the next generation of "green" products will emerge from.

"We are constantly looking for opportunities to develop new products, to increase our offering to our customer base and develop new markets," Mr Wilkins added.


The Dale Electric Group of Companies began in 1935, starting out as one man operating from his garden shed. In 1938 Erskine was founded and 30 years later was acquired by Dale Electric. In 1980 Dale opened the Dale Ottomotores generator manufacturing plant in Mexico.

Dale was acquired by TT electronics plc in 1994 and a year later the group also acquired Munradtech, Dawson Keith and Scorpio, five years later merging the brands. In 2009 offices were opened in Swindon, Aberdeen and the Middle East.

Its main UK office is now on the Eastfield Industrial Estate in Scarborough with its European Development and Test Centre at nearby Filey.

It has sales and service offices in Aberdeen, London and Swindon and in Brazil, Mexico and the United Arab Emirates.

Dale Power Solutions plc

Phone: +44 (0)1723 583511     


The ever-increasing political pressures on the global power generation industry to meet demanding climate and energy targets is driving the increased use of renewable energy sources such as wind and solar power. As a result, electricity generation is becoming more decentralised and more intermittent. This calls for new types of power grids with both the flexibility and intelligence to receive generation of all qualities and quantities from diverse sources, and the capability of managing them to deliver reliable consumer supplies, explains Michael Lippert, Saft ESS (Energy Storage Systems) Division

Much of the debate on the nature of these new smarter grids has been focused on issues such as clean power generation, smart metering and information. Now though, there is a growing appreciation that smarter grids will almost inevitably feature some form of energy storage to provide the vital continuity and quality of supply needed to ensure electricity is available wherever and whenever demand - rather than supply - dictates.

A specific area where energy storage is set to make an early impact on smarter grids is in helping to boost self-consumption in grid-connected solar PV (photovoltaic) installations.

Boosting self-consumption for on-grid PV installations
By 2020, PV is expected to account for up to 12% of all generation in Europe, with a total installed capacity of some 390GW, with two-thirds of this being decentralised (source EPIA: ‘paradigm shift scenario'). PV installations with a permanent connection to the electricity grid are categorised as ‘on-grid' applications. This is currently the most popular type of PV system for homes and businesses in the developed world, comprising more than 90% of all PV installations.

A typical domestic PV installation in Europe, such as those now especially popular in Germany and Spain, is sized to deliver around 3,000kWh/year. With the average yearly energy consumption in those two countries running at 3,500kWh it is clear an energy conscious household with an efficient PV system could be capable of meeting all its energy needs itself. However, the current practice is to inject all of the PV energy produced by domestic schemes into the local electricity network, to be sold to the local utility. The household still imports all the electricity it needs from the network.

In the near future, it is expected we will see a significant change in this operating model as households aim to become energy autonomous. This means they will both produce and consume their own electricity, using a local energy storage system to store any excess PV energy until it is needed. In essence, the PV energy produced will need to be ‘time-shifted' from the day-time, peaking at noon, to make it available on demand in the evening.

The introduction of energy storage will both maximise local consumption and enhance the efficiency of the PV system. Only surplus energy would be fed back into the grid, and it is even possible the owner of the PV system might be remunerated at a higher tariff during peak demand periods. The indications are future legislation in Europe will favour this type of ‘self-consumption', especially as the clear indication of the change in energy value and availability throughout the day will encourage households to adopt a much more energy conscious attitude.

Security of supply and deferment of grid upgrades
In addition to helping the shift towards self-consumption, energy storage can also increase security of supply while making individual consumers less dependent on the grid. This will help to stimulate the development of energy self-sufficient houses and buildings and contribute to the continuous growth of PV as part of the global energy mix.

For utilities, the main benefit of on-grid energy storage is it will reduce the peak load on their grid while at the same time making PV a source of predictable, dispatchable power they can call on when needed. There is also the potential to defer costly grid upgrades needed to meet increasing demands for power.

The anticipated implementation of smart metering and real time pricing will enhance the use of demand side management techniques and serve as a major tool to help balance load versus demand in future distribution networks. With such market mechanisms in place, end users can play an active role in optimising energy consumption whilst maximizing the ROI (return on investment) of their PV system. Energy storage enables them to do this without any reduction in their home comforts.

On-grid energy storage - the operational model
A typical residential PV system with a panel size of 3kW produces a daily average of 8.5kWh throughout the year in Northern Europe, ranging from 3kWh in winter to a peak of 12kWh in summer. About 4.5kWh of the PV energy will be used directly (self-consumed), as soon as it is produced. There is therefore an average excess of 4kWh - with a seasonal range of 1kWh to 6kWh - that can then be stored until needed. So an energy storage system will need to ‘time-shift' between 1 and 6kWh per day - averaging 4kWh.

Li-ion battery technology
In grid-connected energy storage applications, the newest practical battery technology, lithium-ion (Li-ion), offers the potential for significant improvements in terms of performance and service life over conventional storage batteries, and it is also zero-maintenance. However, although Li-ion batteries are very well established in consumer applications, the more rigorous demands of PV applications means ordinary consumer cells are not suitable. Instead, a new generation of Li-ion battery systems designed specifically for industrial applications is under development, with the first systems already on field test.

The initial indications are Li-ion technology will offer both very high efficiency, of around 95%, combined with a long calendar and cycle life - 20 years at 60 percent DOD (depth of discharge)/day.

The compact, sealed for life design of Li-ion batteries also offers considerable advantages. Considering a minimum capacity of 5kWh, then using Li-ion batteries it would be possible for a compact domestic battery to only take up 50 litres or so of space - similar to the footprint of a fridge-freezer.

Guadeloupe grid-connected energy storage project
A current project on the Caribbean island of Guadeloupe is testing the viability of using Li-ion batteries in conjunction with PV systems. 15 PV systems have been deployed over 10 sites, each consisting of an array of 2kW PV panels and a 210/280 V, 10kWh Saft Li-ion battery system that provides buffer storage for the grid-connected PV units.

During peak periods, the PV systems provide a controlled injection of 4kWh daily to the grid, upon utility demand - one hour in the morning and three hours in the afternoon, simulating the substitution of fuel powered generators.

Results from the two-year test period have shown the average daily cycle for the batteries is 45% DOD. This corresponds to about 50% of the generated PV energy stored at a battery efficiency of 97%. The expected payback time on the investment is between six to 10 years, depending on the prevailing cost of peak power.

US DOE SEGIS and SMUD projects
A Saft Li-ion battery system, sized at around 10kWh, will provide energy storage for one of the ‘Solar Energy Grid Integration Systems' (SEGIS) projects funded by the US Department of Energy (DOE). The objective of the SEGIS program is to develop high performance products that will allow PV to become a more integral part of household and commercial smart energy systems.

Similarly, a Saft Li-ion battery will supply renewable energy storage for the Sacramento Municipal Utility District's (SMUD) PV storage pilot programme at Anatolia, Ill, a high penetration PV community within SMUD's service territory. The two-year pilot project is being funded by the DOE to examine the value of distributed PV coupled with energy storage in 15 homes and three sites on SMUD's distribution system within the community.

Efficient energy storage will enable solar power to be time-shifted to support SMUD's ‘super-peak' from 4pm to 7pm, particularly when PV output drops off after 5pm

Sol-ion, Europe's largest PV energy storage development project.
In the EU-backed Sol-ion project, Saft has joined forces with industrial partners Voltwerk and Tenesol, as well as with French and German research institutions. The aim is to create an integrated energy conversion and storage kit, capable of production on an industrial scale, for decentralised on-grid, residential PV systems.

The development phase of the project, which commenced in August 2008, has been completed recently, and it is now moving into its test and evaluation phase. This involves the deployment of 75 Sol-ion energy kits for field trials across France and Germany.

The Sol-ion trials will see Li-ion (lithium-ion) batteries used in PV systems on the largest scale ever tested in Europe. The trials will be used to assess the performance of the technology, its economic viability, the added value of energy storage in an on-grid system and the benefits to stakeholders. The project will also investigate the impact of energy storage on demand side management issues such as peak shaving effects and the potential for integration within future smart grid concepts.

The Sol-ion kit has been developed to accommodate PV energy production of 5kWp (peak) with a battery rated from 5 to 15kWh and a nominal voltage of 170V to 350V. Li-ion is the only technology that meets the project's need for 20-year battery life in demanding environmental conditions.

The energy conversion and system management systems are designed to handle four system functions: multidirectional energy flows; self-consumption; grid support; back-up. They are also intended to handle requirements for demand side management such as control over storage and loads using smart metering, and integration within future smart grids that will need to handle demand response and dynamic pricing.

The Sol-ion battery is based on Saft's high energy Li-ion modules, with a nominal voltage of 48V and 2.2kWh capacity. These compact, maintenance-free modules feature an advanced and robust industrial design, and they can easily be connected in series or parallel to create the desired voltage and capacity for each installation.

- Energy storage is a vital element in smarter grids
- Distributed on-grid PV systems with battery energy storage can effectively ‘time-shift' production, making electrical power available when it is needed.
- Decentralized storage provides value to all stakeholders
- Li-ion is a promising energy storage technology and industrialized systems are being developed and trialled

There is a lot of debate about the use of biofuels in the press.  David Hatherill, engineering manager for Finning Power Systems, takes a closer look at what needs to be considered for its use in generator sets

In recent years there has been an increasing interest in the use of liquid biofuels for fuelling compression ignition engines. With world production of biofuels, such as biodiesel, increasing at an average annual growth rate of 40%, there can be little doubt this interest is set to continue.

It is necessary, therefore, to understand the different aspects that affect which fuels are viable and which are not, taking into account the factors that are important to the engine in a generator set.

When used in its broadest sense, the term biofuels can be confusing, After all, wood is a biofuel, so some form of classification is clearly needed.

Liquid biofuels include not only oils that are liquid at room temperature, but also materials that are solid in their normal state but, when heated, form a liquid containing combustible energy. They are largely derived from vegetable oils, such as rapeseed oil, palm oil and soyabean oil, or animal fats, such as tallow and chicken fat.

In addition to vegetable oils and animal fats, the use of waste materials, such as sewage, to grow algae may play a big role in the future development of biofuels. It is predicted fuel derived from the growth of algae has the potential to produce 30 times more energy per acre than land crops, such as soyabeans.

Some of these sources are available domestically and can play a part in reducing our dependence on imported oil.

Biodiesel is a subset of liquid biofuels and is specifically a non-petroleum based diesel fuel. The production of biodiesel involves reacting vegetable oils or animal fats catalytically with a short-chain aliphatic alcohol, typically methanol or ethanol. This reaction, known as transesterfication, produces an alcohol ester that possesses physical properties very similar to petrochemical based diesel fuel. 

This fuel can be used in most standard diesel engines as the primary fuel source. To fuel an engine, biodiesel can either be used alone, as 100% biodiesel, or can be blended with conventional petroleum diesel. A 100% blend of biodiesel is known as B100. If biodiesel is blended with conventional petroleum diesel, this figure reduces. For example, a blend of 20% biodiesel with 80% petroleum diesel would be referred to as B20.

The current European standard describing the minimum requirements for biodiesel is EN 14214. It is anticipated this standard will be revised in the foreseeable future, due to the fact EN14214 was originally an RME (Biodiesel made from rapeseed) standard and has some deficiencies when applied to biodiesel from a broader range of feedstocks.

In principle, biodiesels conforming to EN 14214 can be used at up to 100% in diesel engines. However, some third party fuel injection equipment (FIE) manufacturers have warned against using over 5% biodiesel blends, as their equipment was not designed to run on such fuels.
Some manufacturers do, however, provide biodiesel compatible components. Seeking expert advice from the manufacturer or dealer is therefore advised.

Fuel standards
Most engine manufacturers set their own standards for liquid fuels, and in general these are wider than the universal fuel standards within any given market: EN590, BS2869 etc.  Manufacturers will be able to advise on the relevance of such standards and also interpret which are relevant to a specific project.

Fuel quality impacts far beyond its combustibility so it is important to work closely with your service provider to develop a suitable maintenance regime.

The major advantage of biodiesel fuel is that it can be produced from spent oils including by-products from other industries, such as used cooking oils, although careful control of feedstock is required to ensure consistent quality.  The emissions from biodiesel engines can be significantly less polluting than standard diesel fuel as they contain little to no sulphur, but adjustment of the engine is required to meet these levels. A non-adjusted engine will generally produce more nitrogen oxide than the same engine on mineral diesel.

Density and calorific value
Whilst the density of biodiesel is slightly higher than conventional petroleum-based diesel, the calorific value is slightly less. This means a greater volume of biodiesel must be injected to achieve the same power output as petroleum diesel.

If a particular unit is only going to be run on biodiesel, it may be acceptable to adjust the injection system to cater for any loss of power. However, if a unit is to be run on either fuel, such adjustments in the injection system may cause the engine to over fuel when run on petroleum diesel.

Cold weather performance
The properties of biodiesel are such that its waxing and cold filter plugging point (CFPP) occurs at much higher temperatures than petroleum diesel. The application and location in which the biodiesel is to be used must therefore be taken into consideration. It may be necessary to use a fuel additive to prevent filter plugging, but these can be expensive.

Lubricating oil degradation
The use of biodiesel and raw vegetable oils has been linked to problems regarding the degradation of engine lubricating oils, with early oil changes often being required. As a result, most engine manufacturers recommend regular Scheduled Oil Sampling (SOS) until this factor is better understood and biofuel tolerant lubricating oils are available. Current lubricating oil blends are designed for mineral fuelled engines. As more biodiesel applications are installed it is anticipated the oil industry will begin to provide specialist oils.

Since biodiesel is an effective solvent, there are a number of potential issues associated with its storage. Existing tanks should be thoroughly cleaned before storing biodiesel, as any existing sludge is likely to be dissolved, which may lead to blocked fuel filters.

Biodiesel is known to dissolve some of the paints used to coat the inside of fuel storage tanks. It is also known to react with copper, bronze, brass, lead, tin and zinc. Stainless steels and aluminium are unaffected. Fuel supply and storage systems should be built with this in mind.

Plastic tanks should be avoided, unless known to be compatible. Some nitrile and natural rubbers are also known to be affected by the use of biodiesel.

Further to this, it should be noted biodiesel has a limited storage life. It is recommended biodiesel is used within six months. After that period, the fuel should be reanalysed to ensure it still meets EN 14214 specifications. Additives are available to extend the storage life of biodiesel.

Other vegetable oils
It is advisable to check with the engine manufacturer before considering other vegetable oils as potential fuel sources. 

They are rarely recommended and on balance do not work in the long term unless additional fuel conditioning infrastructure is installed. If this is not used, engine performance and emissions will rapidly deteriorate. This is due to incomplete combustion and the build up of large amounts of soot in the combustion chamber.

A quick search of the internet will produce a plethora of reports charting the demise of various test engines that have used a variety of crude vegetable oil fuels without fuel conditioning. It is possible to fuel larger, heavy fuel engines with untreated vegetable oils after some on site pre-treatment, but such systems are only economic from about 2-3 MWe upwards. In short you should always consult the manufacturer or dealer.

Finally, one of the most frequently asked questions by an end user is how the use of biofuels affects their warranty.

This is a question that needs to be answered by each individual manufacturer, but for illustration I can outline Caterpillar's stance.

Caterpillar warrants the engine against defects in material and manufacture and will do so on any engine using biofuel.  It follows, however, any damage caused as a direct result of using biofuel could not have been caused by a defect in material. To this end it is advisable the fuel specification should be agreed in advance with the manufacturer.

The debate about using Biofuels will continue to rage.  You should seek professional advice if you are considering such an option; after all generator sets for standby power or as a prime mover are a big investment.

For years the UK has been slow in realising the potential of solar photovoltaic (PV) cells as an electricity source, relying on the more conventional energy sources we are all used to, such as oil and coal. However, it's hard to turn on the television these days without hearing about how to save electricity or cut down our carbon footprint. As an electrical contractor, it doesn't matter if you're worried about your carbon footprint or not, the potential to earn money out of this green frenzy is energising enough says Emma Hughes, Solar Power Portal UK

Back on 1 April, the UK government's Department of Energy and Climate Change (DECC) introduced the feed-in tariff (FiT). This government-backed support measure is designed to increase the uptake of microgeneration and help deliver the UK's 2020 renewable energy targets. It does this by providing those generating renewable energy with a 25-year guaranteed per unit support payments (p/kWh) for electricity generation. These payments, which are currently set at 41.3p/kWh, are paid by the energy supplier. This reward means by installing a solar system of just 2.5kW you could cut up to £9,000 off your electricity bills and earn up to £40,000 over the 25 years the FiT is paid for.

The incentive to install solar PV is clearly there; you could earn a significant profit over the time period the FiT is paid for. Furthermore you can save money on your electricity bill and look after the environment at the same time. However, you have to be properly certified to install a system on your house, and this is where the government comes into play again.

The Microgeneration Certification Scheme
Solar PV forms a key technology set within the Microgeneration Certification Scheme (MCS), which offers government (DECC) grants for the installation of microgeneration based products and systems. To benefit from the UK's feed-in tariff, every installer of solar PV in the UK must, by law, have MCS accreditation.

The MCS is an internationally recognised quality assurance scheme and mark for LZCT installers as well as products, which was designed with input from installer and product representatives. Similar to the Gas Safe Register, the MCS gives the installer a mark of competency and demonstrates to customers the installer is able to perform to the highest quality every time.

Since the solar industry is set for quite rapid growth, installers should aim to become certified as soon as possible, since they will be the preferred option in order to earn the FiT. The DECC links MCS to many of the key factors driving demand, such as:
- FiTs, which will provide guaranteed payments to individuals, business and communities for small-scale electricity generation. For technologies where there is an MCS standard, both the technology and the installer must be MCS certificated to be eligible;
- The Renewable Heat Incentive is planned for 2011 and will provide cash-back to individuals, business and communities for renewable heat generation. The government has indicated that the Renewable Heat Incentive is being linked to MCS products and installers;
- The Low Carbon Buildings Programme and Energy Saving Scotland home renewables grant schemes (heat technologies only) require MCS certificated products and installers to be used;
- The Code for Sustainable Homes, which is a mandatory requirement for all newly built homes to meet sustainability ratings, including ratings for energy and CO2 emissions. MCS certificated technologies can be used to meet the requirements of this Code;
- Planning permission for consumers for certain renewable energy technologies has now been made a lot simpler thanks to permitted development rights introduced in England and Scotland; and
- The Standard Assessment Procedure (SAP) for Energy Rating of Dwellings recognises MCS certificated products when determining whether products are eligible for inclusion in SAP assessments.

To take advantage of this growing demand installers should be considering the certification process and how they can get involved now.

How can you get involved?
- Become a fully certificated MCS installer company - gain your own certificate;
- Work full time for a certificated MCS installer company - MCS certification is for the company. There are plenty of existing MCS companies looking for skilled staff; or
- Become a sub-contractor to a certificated MCS installer company - if you want to remain independent but feel you would like to work in this field, you could be a sub-contractor to an MCS certificated company. See rules for subcontracting within the installer standard.

Training and courses
Alongside MCS certification, it is also important to learn how to work with this up-and-coming technology. The installation process is not difficult for a fully-qualified electrician to grasp, yet it is slightly different from the technology worked with on a day-to-day basis.

Since the introduction of the feed-in tariff, more and more courses have appeared for installing solar photovoltaic systems. Some of the courses are offered by MCS certified companies, giving electrical contractors the opportunity to learn about the systems they will use for free. Some will be trained on the job, adding a practical element to their course. It is important the course details are fully researched before paying out any money, as an illegitimate course is as good as not taking a course at all.

The NICEIC has announced details of a new solar photovoltaic course it has developed to support its MCS for installers. The course provides electrical contractors with knowledge and skills about this energy generating technology. The new course covers the majority of small-scale systems currently being installed in the UK and provides an overview of the design, installation, commission and service of solar PV systems.

"NICEIC is at the forefront in promoting microgeneration and we encourage all electrical contractors to get involved with this growing sector," said Wayne Terry, NICEIC's head of energy and environment. "NICEIC's new Solar PV course provides an excellent way to acquire the necessary skills and knowledge to maximize the revenue generating opportunities microgeneration offers."

Is the future really bright?
Following the right path to becoming a certified electrical installer is all well and good, but if the market doesn't accelerate, there will be too many installers and not enough jobs. Luckily, since the introduction of the FiTs, this problem has faded like a battery-powered lamp.

The uptake of solar in the UK has increased dramatically in the past four months, reaching a total of over 11 megawatts according to energy regular Ofgem. This figure is expected to climb yet more over the next 12 months, as more and more free solar installation offers appear. Several companies are now appearing on the market, offering to ‘rent' rooftops for the installation of solar PV. These companies then benefit from the FiTs, while the homeowner gets to shave pounds off their electricity bill and make use of renewable energy.

This is a win-win situation for all, especially qualified electrical contractors. With these companies experiencing momentous interest in their offer (one company receiving five calls per second), the outcry for installers is hard to ignore. Offers such as these, which will spur the growth of the industry, as well as making others aware of the profit potential available, will increase the amount of jobs obtainable on the market for electrical contractors.  

Light at the end of the tunnel
While the potential for the UK solar market has been planted, the seed cannot grow effectively without the nurture of education. The information outlined within this article is readily available, should you know where to look for it. However, someone needs to turn that light bulb on for many. One such helpful resource in this fledgling industry is the Solar Power UK 2010 Conference, the first official event of the Solar Power Group, a division of the REA and the voice of the solar power industry in the UK. This two-day conference and exhibition will offer insights from top experts in the field, to all the different issues facing this up-and-coming market. It will be the first step in uniting all the major players in the UK solar industry to enable the UK solar market for 2011.

An exclusive gala networking dinner will be held as an accompanying event to the conference, thus opening the opportunity for further networking and business development in an elite environment. Electrical contractors will have the opportunity to meet and talk with qualified installers, to learn through industry experience how the PV industry really works, and to hear what it is like to be part of it. For more information and to register for the conference, please visit http://www.solarpowerportal.co.uk/spuk10 and enter the following code: "RESONATE483"

As UK power grid conditions give rise to extended power outages, long term generator autonomy is becoming an essential complement to the UPS's ‘no break' power protection capability. Uninterruptible Power Supplies generator manager, Kevin Ashton, considers how to match a generator to the onsite UPS, critical load and environmental conditions (PART 1 OF 2)

Uninterruptible Power Supplies (UPSs) perform an essential role in protecting organisations that cannot tolerate any electrical power interruption. If the mains fails, the UPS's battery seamlessly takes over until power is restored. However, UK electricity grid problems are increasing the likelihood of extended failures that could exceed the UPS battery's available autonomy. A standby generator and fuel supply can solve this, but unlike a UPS, a generator cannot come online seamlessly when the power fails. Therefore a matched generator - UPS pair is essential for truly uninterrupted, ongoing power protection.

To successfully install a generator, it must be matched to the UPS, sized correctly for the onsite load, and installed into an environment that is designed to accommodate it.

Generator-UPS matching is important as otherwise each can cause problems for the other. Generator output voltage is usually acceptable to the UPS, but its output frequency range, under fluctuating loads, may be too wide for the UPS to accept. The generator frequency rate of change, or slew rate, may also be too fast for the UPS to follow safely. Such problems can be prevented by ensuring the generator is fitted with an electronic governor maintaining its output within tight frequency limits.

Meanwhile, UPSs typically have a rectifier charger control circuit which imposes notches on the power feed, interfering severely with some types of generator control. Additionally, some charger circuits draw non sinusoidal input current, creating harmonics, measured as total harmonic distortion (THDi). These can cause de-rating of the generators output, especially as some UPSs generate up to 30% THDi. Also, generators cannot usually tolerate 100% of their rated load being applied in a single step.

However, careful choice of UPS topology can pre-empt such problems. Transformerless technology can achieve a THDi of below 3% at full load, while a separate battery charger circuit, together with a Generator 'On' signal between UPS and generator reduces the UPS battery charging current, in turn reducing load, notching and heating effects on the generator. Step loading on the generator is controlled primarily by soft start of the rectifier current, eliminating high current peaks during mains recovery. Sequential switch-on of UPS rectifiers as a parallel array within the UPS is another possible way of reducing UPS step loading on the generator.

The generator must be sized for its critical load as well as matched to the UPS. This may comprise emergency lighting, air conditioning, building alarm systems and other services as well as the UPS load. For example, there is no point in maintaining power to ICT equipment without also supporting the air conditioning essential to maintaining equipment-acceptable ambient temperature. It is also good practice to work to the generator's continuous rating rather than its higher standby rating, as it can be called upon at any time to work for any duration.

Planning the chosen generator's installation is subject to several environmental and physical considerations. Once the autonomy has been established, the amount of fuel required and means of storage can be established. Bunding is essential to ensure fuel oil cannot leak into the water supply. Positioning of the generator is influenced by further factors that must all be allowed for. For example generator start-up and running noise may be acceptable in a given location during the day, but intolerable at night. As the mains can fail at any time, either a different location must be chosen or a ‘bespoke' acoustic housing used. The cost of this increases with its attenuation rating.

All generators produce heat as well as power, which is mostly removed by air cooling. Therefore, generators are typically located outside, in weatherproof and acoustic enclosures, where a plentiful supply of cooling air is assured. An outside location also allows easier exhaust fume venting, obviating problems associated with installing exhaust pipes within buildings. For internal installations within buildings ventilation and noise requirements can be given using specialist acoustic equipment such as attenuators and exhaust silencers. These are often manufactured specifically for the application and the complete system assembled on-site by specialist installation engineers. 

Other physical considerations are also important. Even a small 100 kVA standby generator weighs several tonnes, weight which must be allowed for when planning its delivery and positioning. Special delivery vehicles and lifting equipment may be needed. The generator should also be as close as possible to the main electrical installation to minimize runs of expensive power cable, as well as volt drop losses.

Adding a generator calls for legislative compliance as well as satisfying the site's environmental considerations. Local authority planning requirements vary with area, so it is essential to check these before installing a standby generator. If large quantities of fuel are to be stored on site then compliance with the Environment Agencies PPG02 regulation is required.

All of these factors are important to the success of adding generator capability. However, with planning none are particularly onerous, and the benefits of generator protection can far outweigh any inconvenience or cost.

In general, test cabling and test connections must all be designed to minimise resistance (R), capacitance (C), and inductance (L) between the device under test (DUT) and the used source-measure unit (SMU) explains the applications engineering team at Keithley Instruments

To minimise resistance, use heavy gauge wire wherever possible, and definitely within the test fixture itself. The gauge required will depend on the level of current being carried; for example, for cabling that must carry 40A, a 12 gauge cable is probably necessary. For guidance on choosing cabling for higher current levels, refer to construction industry wire gauge tables, such as the one available at: www.powerstream.com/Wire_Size.htm. Check the ‘Maximum amps for chassis wiring" column to find the wire gauge needed to carry the level of current involved.

Low-resistance cabling is critical to preventing instrument damage. Choose cables with resistances of less than 30 milliohms/meter or lower for 10A pulses. Keep cable lengths as short as possible and always use low-inductance cables (such as twisted-pair or low-impedance coax types), heavy gauge cable in order to limit the voltage drop across the leads. Ensure the voltage drop won't be excessive by checking the SMU's Voltage Output Headroom spec. For example, if you were using a Keithley Model 2602A (pictured above) SMU to output 20V, the test leads should have no more than 3V of voltage drop across them to avoid inaccurate results or instrument damage. It is specified for a maximum voltage of 3V between the HI and SENSE HI terminals and a maximum voltage of 3V between LO and SENSE LO. 

Although many believe guarding can minimise the effects of cable charging, this is typically more of a concern for high voltage testing than for high current testing. Four-wire Kelvin connections must be kept as close to the DUT as possible; every millimetre makes a difference.

Also, it should be noted 0voltage readback should be done with the SMU that's forcing voltage, because the current-sourcing SMU's voltage readings will all vary quite a bit due to the connections, and will differ from what is actually seen at the DUT.

The jacks used on the test fixture should be of known high quality. For example, some red jacks use high amounts of ferrous content to produce the red colouring, which can lead to unacceptably high levels of leakage due to conduction. The resistance between the plugs to the case should be as high as possible and in all cases >1010 ohms.

Many published test setups recommend adding a resistor between the SMU and the device's gate when testing a FET or IGBT. When pulsing large amounts of current through these kinds of devices, they tend to oscillate. Inserting a resistor on the gate will dampen these oscillations, thereby stabilising the measurements; because the gate does not draw much current, the resistor does not cause a significant voltage drop.

If voltages in excess of 40V will be used during the test sequence, the test fixture and SMUs must have the proper interlock installed and be operated in accordance with normal safety procedures.

Many electrical test systems or instruments are capable of measuring or sourcing hazardous voltage and power levels. It's also possible, under single fault conditions (e.g., a programming error or an instrument failure), to output hazardous levels even when the system indicates no hazard is present. These high levels make it essential to protect operators from any of these hazards at all times. Protection methods include:
- Verify the operation of the test setup carefully before it is put into service.
- Design test fixtures to prevent operator contact with any hazardous circuit.
- Make sure the device under test is fully enclosed to protect the operator from any flying debris.
- Double insulate all electrical connections that an operator could touch. Double insulation ensures the operator is still protected, even if one insulation layer fails.
- Use high reliability, fail-safe interlock switches to disconnect power sources when a test fixture cover is opened.
- Where possible, use automated handlers so operators do not require access to the inside of the test fixture or have a need to open guards.
- Provide proper training to all users of the system so they understand all potential hazards and know how to protect themselves from injury. It's the responsibility of the test system designers, integrators, and installer to make sure operator and maintenance personnel protection is in place and effective.

The need to protect IT equipment from the effects of power transients, as well as to provide assured operation during power outages is evidenced by the steady growth in sales of uninterruptible power supplies (UPS) up to the global downturn of 2008 - 9 (IMS Research). As markets start to bounce back post global downturn, the sales of UPS equipment has started to recover and are predicted to return to real growth during the coming 2 - 3 years. Michael Adams, global vice president for data and IT at AEG Power Solutions, explains

With IT central to the successful operations of most modern organisations, the UPS has a central position in the critical physical infrastructure which supports servers, storage and communications equipment, and which ensures continuity of services during all local mains conditions.

Recently, escalating energy costs and increasing concern about the carbon footprint of organisational power requirements, has driven the need to consider alternative back-up technologies and evaluate their effectiveness to ensure ‘business as usual' has become pressing.

Pressure on IT and facility managers to utilise green technologies, especially in Western Europe, continues to grow. In addition to the environmental benefits associated with lower carbon footprint, green technologies bring with them lower operating expenses by virtue of their more efficient operation and ability to deliver ‘more with less', i.e., more compute cycles from less energy.

As a discipline, energy storage technology has acquired new levels of prominence as methods are sought to overcome intermittency issues associated with solar and wind power generation. Smart grid concepts are being tested which are likely to promote an increasing trend towards distributed power generation combining traditional power sources with renewable or green power sources.

The eco-friendly storage industry is currently small, but solutions are either on the verge of commercialisation, or are starting to experience mainstream uptake. But another wrinkle is posed by the fact the choice of energy storage solutions is highly application-specific, as it varies as per application and requirement of the end-user.

Supercapacitors, or SuperCaps, are not a new concept and their effects were first noted in the late 1950s. Consequently, the technology is well established; has experienced significant advances over the last 10 to 15 years and has also seen recent reductions in cost. At the moment, supercapacitors have been successfully adopted in three different sectors; transportation, industrial and consumer electronics.

Why should we consider SuperCaps in UPS applications?
SuperCaps core technology is environmentally friendly and offers a high power density (4000W/kg). It has low internal resistance (ESR) and can operate in a wide temperature range which is very useful for data centres. The systems also offer a low total cost of ownership (TCO) and are capable of over one million cycles and offer instant recharging.

There is no doubt there have been significant developments with battery technology over the years, but despite all these advances, they all suffer from the same basic problem in that they utilise a chemical reaction. This means they suffer from a limited life, and can only operate in a limited temperature range.

In addition, traditional batteries that experience constant high demands for current, have a shortened operational lifespan. Therefore in order to ensure reliability and long lasting cover, facility managers are forced to deal with higher maintenance costs.

It is well known batteries die after a period of time, and need replacing on average, every two, five or seven years. Any technology that can offer a longer lifetime, so that users do not have to spend their precious budget repeatedly on replacement batteries, will prove to be a big incentive.

The SuperCap UPS provides a useful alternative solution in this context as it is ideally suited to provide a short-term ‘bridge' power until standby power generation equipment kicks in. As the SuperCap industry continues to experience a lot of R&D and maturation, SuperCap UPS systems are now becoming highly competitive with, and in many cases superior to, older bridge technologies.

TCO Considerations
Offering a wide temperature range, long life, and flexible voltage range, SuperCaps provide an extremely reliable solution for bridge power.

The very high cycle life of a SuperCaps UPS means unlike lead acid batteries, there will likely be little or no need for constant replacement. The facility to repeatedly charge and discharge for up to a million cycles without disintegrating, means the lifetime cost of the SuperCap is expected to break even with lead acid batteries.

Longevity is helped by the fact their high power density results in reduced strain on the battery in times of need. Another major consideration is the fact the SuperCap also has the ability to recharge instantaneously, in a few seconds. This is really useful in data centres, to help cut power costs associated with keeping batteries charged.

Another important factor is the ability of SuperCaps to offer versatile functioning in a wide temperature range, dramatically reducing cooling costs. This is because the function of a SuperCap does not require a chemical reaction, and therefore, does not involve an optimal temperature range for best performance or longevity.

It has been estimated the supercap can be used from -40°C to +70°C, without degradation in its performance characteristics. This is in stark contrast to the lead-acid battery, which when used in industrial applications, almost always requires a mechanically cooled environment.

Pros and Cons
The SuperCap is green in two ways. Firstly, it reduces waste because it has a very high cycle life, and therefore decreases disposal issues. Secondly, the materials and substances used in the SuperCap UPS are toxin free and biodegradable, e.g., nano carbon particles are commonly used. They can operate in a wide temperature range without any degradation of performance characteristics, and it also has the ability to recharge instantaneously in a few seconds.

SuperCaps are ideal energy storage devices for fast and short-term peak power delivery, which is why they are so suited for UPS systems. They are also more efficient than conventional batteries as they do not release any thermal heat during discharge, and various figures have shown that they operate at around 80% - 95% efficiency in most applications.
SuperCaps also take up much less room compared to lead-acid batteries, and indeed weigh less as well, which can be an important factor in certain situations or locations. The table below contrasts the pros and cons of SuperCaps with traditional UPS technology.

There is no doubt the industrial market needs an energy storage solution that is both reliable, and can offer a quality service. SuperCaps offer high power density, cycle life, and thermal susceptibility, and the increasing adoption of renewable energy expands the possibilities of using SuperCap-based technology.

Frost and Sullivan points out the total world ultracapacitor (SuperCap) market had generated revenues of $113.1m (£75m) in 2008 and is likely to reach $381.9 (£250m) by 2015. It feels this market has witnessed growth (despite the economic situation) due to the great interest in propelling alternative energy storage mechanisms by governments. Indeed, Europe has given the highest priority to any environmentally friendly technology and has a proud tradition of being one of the first global markets to accept new technology and consider its applicability in various solutions.

The high price of oil, coupled with high electricity costs, the need for devices that can reduce the power burden of a data centre represents a significant opportunity. The increasing use of supercap technology within the transportation industry will also serve to spur new developments and help drive down the initial cost of ownership.

Electrical contractors can not and must not take the recycling of fluorescent bulbs lightly says Terry Adby

How many electrical contractors does it take to change a light bulb? It doesn't really matter, because, with the double focus nowadays on health and safety and sustainability, the real question should be: "Do they know what's being done with the old one?"

As efficient electrical waste disposal gets both more complex and more necessary - for financial, operational and legal reasons - those involved in electrical engineering and building services would be unwise not to pay heed to the answer, a fact that one recent prosecution has shed some revealing light on.

The sustainability lobby's continued success in promoting the balancing of successful business with effective environmental protection (not to mention the wellbeing of the immediate workforce) has ever greater ramifications for the industries responsible for creating and managing the built environment.

Sustainability, above all, is an area where electrical contracting, now worth some £8bn per year, has a key role to play, with the opportunity to propose ‘low or no CO2' options. But to play its role successfully the industry must also pay close attention to the matter of the waste the ‘alternative' option creates, and how it is disposed of.  Developments such as the WEEE regulations (Waste Electrical and Electronic Equipment Directive) impose legal obligations on contractors over the management of ‘waste streams' onsite, and in their subsequent disposal. It aims to "improve the environmental performance of businesses that manufacture, supply, use, recycle and recover electrical and electronic equipment" and has put the practical management of sustainability centre stage. For the electrical contractor its implications are unavoidable.

Energy efficient light bulbs (‘end-of-life gas discharge lamps') are covered by the WEEE regulations and present a particular challenge, because they contain mercury and are classified as ‘hazardous waste'. When these lamps are recycled the potential release of mercury into the air at the lamp crushing stage is a threat to both the wider environment and those in the vicinity if the right protective equipment is not in place. Each time a fluorescent bulb is crushed or broken, mercury vapour is released. If the gas is not effectively captured, that vapour will find its way into the atmosphere, the staff and others in the area.

The challenges of lamp recycling made headlines earlier this year when a Glasgow-registered company, Electrical Waste Recycling Group, and one of its directors, were fined a total of £145,000 plus costs after recycling processes being used for gas discharge lamps exposed workers to toxic fumes for a period of up to ten months.

If an electrical contractor is going to propose the likes of optimal lighting configurations or energy efficient lighting units, and if they are tempted to employ energy efficiency as a sales tool, they should be confident that the principles and practice that underpin sustainability and safety are being applied all the way through the supply chain, including what happens to the waste.

Bulb crushing on an industrial scale is a serious undertaking that comes with huge levels of environmental responsibility. Nevertheless, electrical contractors may face the prospect, perhaps even at the tendering stage, of client pressure to commit to deliver such a service. Contractors need to be completely confident of the ability of the suppliers they choose to meet their commitments. They also need to know what is being done in their name further down the supply chain.

In the case of Electrical Waste Recycling Group, it was the failure to ensure the safety of the lamp crushing phase of the recycling process at its Huddersfield plant that let down the company, their workforce and the local environment. EWRG, which runs easyWEEE, WERCS (Waste Electrical Recycling Compliance Scheme) and other recycling schemes, were contracted to handle commercial waste for several Local Authorities, which included light bulbs. While none of these clients were in any way implicated along with their supplier, the judgment in the case suggests others in the chain - such as electrical contractors - could be more vulnerable. It has already been indicated in court that putting a service out to a third party does not absolve an organisation of key responsibilities and, in respect of health & safety, the HSE - which brought the successful prosecution in the EWRG case - has said that "The client must ensure whoever carries out the work is able to do so in a way that controls risks." As this case suggests, sustainability and health and safety responsibilities often go hand in hand.

Some of the details of the EWRG judgment highlight the type of issues any business, including electrical contracting businesses, should take into account to ensure they and their suppliers comply with statutory requirements when dealing with waste. The promises of suppliers, the judge made clear, are no defence in the eyes of the law. They must be effectively monitored.

One of the judge's major criticisms was the lack of an effective risk assessment process at the EWRG recycling centre, not least because issues highlighted - such as excessively high mercury levels for no apparent reason - could have been rectified much earlier had risk assessment been in place. It is, in any case, a legal requirement for an employer in discharging their obligations to keep workers and the public safe as far as "reasonably practicable".

The HSE recommends five steps for effective risk assessment: identification of hazards; establishing who might be harmed and how; evaluation of risk and deciding on precautions; recording and implementing findings and regular review. Suppliers in a business as hazardous and regulated as lamp recycling should certainly be implementing all five. Those employing them to do the work should be equally concerned that they are.

The judge in the EWRG case also stressed the need for competent staff to be involved in the process monitoring, who understand the regulations and have the knowledge and experience to spot a breach or issue. Most successful organisations, he said, have employees who understand why risk assessment and vigilance is important for the company, staff and other groups with an interest, such as the local community. 

However, all responsibility cannot be delegated to one individual or team, he added. Senior managers need to put themselves in the position of being able to interpret and understand the implications of the results of any monitoring which is undertaken.  If they do not understand the implications of results, they cannot just ignore them. In the case of a prosecution it will be the senior managers and directors who will be held responsible. It is clear, above all, when things go awry, buck passing between organisations or individuals is not an option.

EWRG paid a heavy price because it did not read nor heed the warning signs. Those looking for lessons from its prosecution certainly should however. The safe recycling of energy efficient lamps may represent a beacon for a better future but, viewed from both an environmental or health and safety perspective, the message for electrical contractors is clear: the responsibility for a safe and sustainable approach to lighting may not end with the life of the low-energy bulb.

Mike Frain of Electrical Safety UK, examines live working on low voltage systems in industrial and commercial facilities, detailing a methodical process for identifying the risks associated with live working and the methods for controlling them

From my experience, I believe Regulation 14 from the Electricity at Work Regulations 1989, referring to live working, is often misunderstood and sometimes overlooked. The duty holder is asked to apply a rigorous test of reasonableness in allowing live work to proceed in the first place, and to prevent injury by taking suitable precautions. It must be stressed that Regulation 14 requirements are ‘absolute' which means it must be met regardless of cost or any other consideration. With this in mind it makes it very important that any live operation must be subject to a suitable and sufficient risk assessment.

Regulation 14 - Work on or near live conductors
A person shall not be engaged in any work activity on or so near any live conductor (other than one suitably covered with insulating material so as to prevent danger) that danger may arise unless
(a) it is unreasonable in all circumstances for it to be dead; and
(b) it is reasonable in all circumstances for him to be at work on or near it while it is live; and
(c) suitable precautions (including where necessary the provision of suitable protective equipment) are taken to prevent injury.
Before we move on, let me highlight a few of the important words from Regulation 14.
Near. This word debunks the myth live working only means those activities that require the manipulation or the removal/replacement of live conductors and components. Live work can also mean live testing and testing for dead. It can also mean the opening of control panel doors to undertake visual examinations or undertake non electrical work near energised equipment. I find that most live working in industrial and commercial facilities is confined to testing, inspections and running adjustments.
Suitably. This word completely changes the meaning of the opening sentence. I often hear when conductors are insulated through finger safe shrouding or cable insulation then live work can proceed with no further precautions necessary. I can name several examples of incidents in switchgear which was finger safe or of Form 4 construction. It is the task or activity near live conductors which will determine whether the insulation is suitable or not. An armoured and insulated underground cable may be suitably covered with insulation where its presence is known and careful location and hand dig techniques are adopted but would not be suitable using a jack hammer without safe dig techniques. Finger safe shrouding, providing it hasn't been removed, may be suitable insulation for routine testing but may not be suitable for the task of drawing in of cables into switchgear enclosures or other similar invasive tasks.
And. Parts a) b) and c) are separated by the word ‘and' which means there is a legal requirement for all parts of the regulation to be satisfied before live work can be permitted.
Danger and Injury. Danger and injury are highlighted in bold and are specifically defined in the guidance documents referred to in this article. Briefly, danger means risk of injury, and injury means death or personal injury from electrical shock, burns or explosion and arcing. For live working, danger may be present but injury must be prevented.
As an electrical duty holder who may be vexed by the questions posed in regulation 14 where do you look for help? Firstly there is the Memorandum of Guidance (HSR 25) published by the HSE. This is usually purchased instead of a separate copy of the actual regulations, to assist with the interpretation of each of the regulations in turn. In addition there is the guidance booklet HSG85 Electricity at Work - Safe Working Practices, also available from HSE Books. Further guidance can be obtained from the HSE website www.hse.gov.uk.
I find HSG85 Electricity at Work - Safe Working Practices is particularly helpful in the decision making process for working live or dead. Simple flowcharts are a feature of this document and one such flowchart is shown below.
It is not my intention to repeat verbatim the advice given in the existing guidance notes but to further expand on this decision making process and to emphasise a methodical process for identifying the risks and the methods for controlling them. I have used the following model many times with duty holders to explain the relationship between the live/dead working decision, task, identification and quantification of the hazard and preventative measures to be taken. As can be seen, this relationship is an interdependent one. It is not sufficient to decide firstly to work live and then devise preventative or protection measures.
To further clarify this relationship, a decision for work to proceed cannot be taken in isolation to other factors. The level of hazard and also the availability and effectiveness of preventative or protective measures will also need to be considered. This is all directly affected by the work task.

Steps to Identify and Assess the Risks and Methods for Controlling them.
The live working decision flow chart Figure 1 illustrates that a critical part of decision making is the identification of risks and the methods for controlling them. I find it useful to break this down into a four step process as follows.
STEP 1:    Equipment and shock hazard
STEP 2:    Electrical flashover
STEP 3:    People and safe systems of work
STEP 4:    Environment
STEP 1 - Equipment and shock hazard
Has the equipment been checked and is it in a safe condition? Check whether the equipment to be worked upon has been examined and in a safe condition for work. Live work should never be permitted where there are any doubts about the safety of cables and electrical equipment being worked upon or even adjacent to those being worked upon. The examination can be visual but also using other senses such as smell and hearing to detect burning or electrical discharge.
Signs of vermin or birds inside switchgear or water ingress is a definite prompt to stop and investigate only when the switchgear is dead and isolated. Approaches should never be made to cables damaged by site traffic or excavation.
Is the equipment finger safe? If the equipment is in a safe condition the next step is to consider whether the equipment is finger safe. If the equipment is not finger safe, can measures such as temporary shrouding be used to prevent contact with live parts? The term ‘finger safe' is defined as no exposed live parts that can be accessed by solid objects greater than 12.5mm as given by IP rating IP2X.
Do not rely purely on the original specification of the equipment. Insulation is often removed and not replaced. If it is not finger safe, or other measures cannot be introduced to prevent contact with live parts then carry out the work dead.
Are tools, instruments and leads checked fit for purpose? If measures to prevent contact with live parts can be implemented, are tools, instruments and leads checked fit for purpose?  Tools and instruments must be of the correct duty rating and their condition must be checked especially test leads. It is important correct instruments and leads should be selected and in particular the correct over voltage installation category in accordance with EN61010-1. The wrong meter and leads can increase the chances of electric shock or the initiation of an electrical flashover due to transient over voltage. Most instrument manufacturers publish guidance about overvoltage on their websites.  
Are you sure the equipment is designed for live operation? There seems to be some opinion that because electrical components ‘plug in' then this operation can be carried out live. Examples of such components are plug in circuit breakers or bus bar trunking tap off units. Always contact the equipment manufacturer if such a live operation is contemplated. You may find the equipment has been designed for flexibility rather than for live operation and the manufacturer may discourage such activities.

STEP 2 - Electrical flashover or arc flash
Is there a significant risk of burns from electrical flashover? I have authored several articles on the subject of electrical flashover in Electrical Review and they can be accessed at www.electricalreview.co.uk. In brief, the severity of the thermal effects of an electrical arcing event is usually expressed in units of calories per square centimetre at the working distance from a potential arc source and the head and torso of the worker. This is called incident energy and a level of 1.2 cal/cm2 is sufficient to predict a 50% chance of the onset of a second degree burn.
Incident energy has an approximate linear relationship firstly; to the amount of current that can flow in the arc and secondly to the time that it can flow before the upstream protective device clears the fault. Note that arcing current does not equal prospective fault current (PFC) and at 400 volts is likely to be less than 50% of PFC. It follows the upstream device may take longer to operate with resulting higher levels of incident energy. Keep in mind also, protective devices need to be maintained to ensure they will operate according to their time current characteristic.
When undertaking arc flash studies for industrial and commercial facilities, I have found, where the upstream protective device is a conventional fuse or fast acting fixed pattern circuit breaker at a rating less than 100 amperes and the voltage is at 400 volts 3 phase and below, then the incident energy levels will be limited. A rule of thumb is to use the good old BS88 Industrial fuse as a model. If the entire time/current characteristic curve of the upstream device can sit below a BS88 100 ampere characteristic curve, the incident energy at a working distance of 450mm is unlikely to exceed 1.2cal/cm2. This does not mean flash burn injury can be totally discounted and severe burns can still be experienced particularly at the hands which will usually be closer any arc initiated when testing live circuits. For comparison, a BS88 400 ampere fuse could present a predicted *20 cal/cm2 at certain fault levels and an 800 ampere fuse could be in excess of *60cal/cm2.
*Note these figures are for indicative purposes only, not to be used in a risk assessment.
Suitable risk control measures must be employed and as a last resort PPE should always be used. In the case of the 800 ampere fuse, PPE is unlikely to fully protect the worker because of the possible ballistic and other effects of a flashover. Regardless of tasks, I recommend electrical workers should not carry out work in high power environments in clothing that can ignite or melt.
If the incident energy at the equipment to be worked on is over 1.2 cal/cm2, then can it be reduced to below 1.2 cal/cm2? As an alternative, can risk controls be put in place to prevent or mitigate arc flash effects and are they adequate? Please refer to my recent articles, available on the Electrical Review web site. If the answer is no to both questions then proceed no further until advice is sought or carry out the work dead.

STEP 3 - People and safe systems of work
Are the workers competent for the task? Regulation 16 from the EAW Regulations 1989 states: "A person shall not be engaged in any work activity where technical knowledge or experience is necessary to prevent danger or, where appropriate, injury, unless he possesses such knowledge or experience, or is under such degree of supervision as may be appropriate for that purpose having regard to the nature of the work."
In the context of live work, technical knowledge or experience means the person should be properly trained and assessed in the techniques being employed but the person must also understand the hazards from the electrical system and be able to recognise whether it is safe for the work to continue at all times including whilst the work is being carried out.
Is the work to be carried out at height? Working on live equipment at height is always a special case for consideration for two reasons:
1. Electric shock or arc flash to a worker at height can bring about a fall with obvious consequences.
2. An arc flash incident whilst working at height may mean that the worker cannot move out of the way because of the limited working space on access equipment. This may be the work platform of a scaffold or a mobile elevated work platform.
If the work has to be carried out at height, can risk control measures to prevent shock, burns and falls be put in place?
Is Accompaniment Required? Anyone undertaking work on or near energised electrical conductors will nearly always require some form of accompaniment by someone who can give assistance in an emergency.  This implies a degree of competence such that the accompanying person can assist without danger to themselves or others.  A requirement for a second person is to ensure safe working procedures e.g. preventing encroachment of non-authorised personnel into the working area.

STEP 4 - Environment
Is access and space adequate? Establish whether the access and space in front of the equipment is adequate to allow the worker to pull back from the conductors without hazard. HSG85 mentions a minimum 915mm measured from a live part or 1375mm when there are live parts exposed on both sides of the worker. The working space may need to be greater than these minimum distances as a result of the electrical flashover assessment in Step 2.
The work area should be clearly defined, with no tripping and slipping hazards and with good means of escape and illumination.  Simple barriers and signs can often be erected for the demarcation of work areas to keep non-authorised staff away and also to protect electrical workers from interruptions at times when they need concentration.
Is lighting adequate? It is also important to check whether lighting levels are adequate for work as well as another requirement in Regulation 15. Use of additional lighting is essential where ambient lighting levels are poor.
Are hazardous conditions present? Check to ensure the immediate environment is free from water or dust. A hostile or wet environment will significantly increase the risk and severity of electric shock and should therefore be subject of special consideration to control the risks. Ensuring there is no possibility of an ignition hazard due to sparks is crucial. If there is a possibility of an ignition hazard, take precautions to remove the hazard before proceeding. There may other local environmental hazards that may need to be taken into account such as automatic fire fighting equipment.

Proceeding with work
After all 4 steps are satisfied, then revisit the flowchart in Figure 1 and confirm the work is justified relative to the precautions, implement safe working and ensure adequate monitoring and supervision. Make sure any special equipment and PPE is properly used and maintained and always keep the duration of any live work to a minimum.

When a power service engineer is called out to deal with a loss of supply on a customer’s HV distribution network, the chances are it will be traced to a faulty underground cable that has caused a device – such as a circuit breaker – to operate and cut-off the power. Danny O’Toole, ABB Power Service, explains

A cable in good condition and installed correctly can last a lifetime - well over 30 years. However, cables can be easily damaged by incorrect installation or poorly  executed jointing, while subsequent third party damage by civils works such as  trenching or curb edging is also another main cause of damage.

Service engineers are usually equipped with a suite of test equipment that enables them to perform an immediate on site check on the key network elements of switchgear, transformers and cables. If the fault is identified in a cable, as it often is, and the network is interconnected, they are then able to sectionalise the problem circuit to restore power to as much of the network as possible, bringing in additional generation if necessary. The next task is to locate the position of the underground cable fault as accurately as possible, since this makes it easier to find and repair so that the full network can be restored quickly.

ABB has developed a fault location regime that has proved very accurate in  locating underground cable faults in both modern XLPE type cables and older PILCSWA (paper insulated lead covered steel wire armoured) designs. Fault location is usually carried out on cable networks up to 11 kV, however the techniques can be applied on cables up to 33 kV.
The main technique employed is the SIM (secondary impulse method) that combines the use of classic high voltage surge generator thumping with low voltage TDR (time domain reflectometry). To see how this works, it is useful to consider the merits of the individual techniques.
Cable thumping
The high voltage surge generator, or thumper, is a portable device that is used to inject a high voltage DC pulse (typically up to 30 kV) at the surface termination of the cable to be tested. If the voltage is high enough to cause the underground fault to break down it creates an arc, resulting in a characteristic thumping sound at the exact location of the fault.

Historically, fault location was carried out by various measuring techniques and by setting the surge generator to thump repeatedly, and then walking the cable route until the thump could be heard. At which point ‘x' would mark the spot to start digging. Naturally, the higher the DC voltage applied the louder the resulting thump and the easier it becomes to find the fault. If the cable is long it could take days to locate a fault by this method. During which time the cable is exposed to potentially damaging high voltage thumping. So while the existing fault might be located, other areas of the cable could have been weakened in the process. Statistically, cables that have been thumped tend to fail sooner than would otherwise have been expected.
TDR (time domain reflectometry) uses a pulse echo range finding technique, similar to that used by sonar systems, to measure the distance to changes in the cable structure. It works by transmitting short duration low voltage (up to 50 V) pulses at a high repetition rate into the cable and measuring the time taken for them to reflect  back from areas where the cable has low impedance, such as at a fault. The reflections are traced on a graphical display with amplitude on the y-axis and elapsed time, which can be related to the distance to the position of the fault, on the x-axis.

A cable in perfect condition will not cause any reflections until the very end, when the  pulse encounters an open circuit (high impedance) that results in a high amplitude upward deflection on the trace. If the cable end is grounded ie a short circuit, the trace  will show a high amplitude negative deflection.

Low voltage TDR works very well for the location of open circuit faults and conductor-to conductor shorts. However, for shielded power cables, it becomes very difficult to distinguish faults with a resistance higher than 20 ohms. Unfortunately, the majority of faults in underground distribution cables are high resistance faults in the area of thousands of ohms or even megaohms.
The SIM (secondary impulse method) technique combines low voltage TDR and a thumper in an integrated system that makes the trace easier to interpret, with a clear indication of the fault location on a handheld display.

The process starts by running a TDR test on a healthy core, this is then stored in the SIM system memory. The thumper is then triggered to send a single HV pulse, and while the arc is forming at the fault the TDR sends a further low voltage pulse. The arc acts as a very low impedance point that causes the pulse to reflect in exactly the same way that it would from a short circuit. The handheld display combines the two traces and the fault location is shown as a large negative dip, with its distance easily read off on the x-axis.

SIM enables a fault to be located to within a few metres, even over very long cable runs of several kilometres. Of course, underground cables do not always take the shortest or most direct route between two points, so it is important to have access to the site cable records. In cases where a map of the cable route is not available a radio-detection system can be used to find the cable, but this could add a considerable amount of time to the exercise. ABB would always advise customers to make a detailed record of their underground cable circuits a priority in their maintenance planning.

Once the target area above ground has been identified, the surge generator is turned on to start thumping the cable. The operator then listens for the thump to home in on the precise location of the fault - this approach minimises the amount of time that the cable is thumped, eliminating the risk of further damage. The next step is to bring in the repair team to dig up the cable, make a visual confirmation of the problem and then effect a repair.

The time taken to locate a fault by SIM varies according to each case, but will typically take around half a day.
Fast track fault location for Silverstone Circuit
Silverstone Circuit, located on the border between Northants and Buckinghamshire, has its own high voltage power network comprising 17 11kV/433V substations that provide local power supplies at key points around the three-mile track. ABB has a long-standing service contract for the network to provide ongoing maintenance and repair services including a fast call-out response in the event of a fault.

At 6am on 1 July 2008 the ABB duty stand-by engineer fielded an emergency call saying that there was a major outage, with a total loss of power to half the site. In normal circumstances this would be a cause for concern. With the British Grand Prix taking place on the Sunday and hospitality organisers and traders already setting up on site, the loss of power threatened to cause significant disruption.

Within an hour, an engineer was on site. After establishing the fault was on Silverstone's own network they opened discussions with Central Networks, the local DNO (distribution network operator) to organise reinstatement of supply. A thorough test and inspection showed the problem was not due to faulty switchgear, but was cable related. So ABB's specialised cable fault location vehicle was called to the site together with spare cable and joints.

While waiting for the fault location vehicle, the fault was successfully sectionalised so that it was isolated from the rest of the network, ensuring it couldn't cause any further loss of power. This step enabled Central Networks to restore full power to the rest of the site at around 9.00am.

The fault location vehicle arrived at 10am, and in less than two hours the cable fault was located to an area beneath the tarmac base under a hospitality marquee erected for the F1 Paddock Club.

The next stage was to expose the identified section of cable for a visual verification of the damage. A further 10m of trench was then exposed to enable a new section of cable to be jointed into place. By 10pm, the jointing operation was finished, pressure tested, energised and phasing proved so that power could be restored to this local section of the network. All that remained was for the trench to be backfilled and recovered by tarmac. So what might have caused very severe disruption in Silverstone's busiest week of the year effectively became a minor incident.

Our grumpy old man's mood has not been lightened by England's recent footballing failures, but the way Forgemasters has been treated has really got his goat

Sorry to be on another quasi-political rant this month, but we British just don't seem to get it right when it comes to competition.

As I write, England have been dumped out of the World Cup at the hands of a rather promising young German team, the abject failure of FIFA to invest in technology that, let's face it, is already mounted in the goals, and most significantly, a lack lustre performance by the men in control - manager and players.

Shortly before the South African debacle however, we scored what in my mind was an even bigger own goal, the coalition government's failure to honour a pledge, made by Labour, to loan £80m to Sheffield's Forgemasters. The money was a loan, not a grant, to enable the company to install a new open die press with which to make large components principally for the nuclear power industry.

This sends out three distinct messages to me. One, our government has no confidence in one of our best heavy engineering companies; secondly there is yet another manifestation of Britain's reluctance to invest in engineering; and thirdly (which is where Electrical Review's readers come in) the failure to recognise the need for such components if we are to press ahead with a nuclear build programme. Readers of this column will know how sceptical I am of this government's commitment to extending our nuclear capacity.

The prize for Forgemasters if it gets its new plant is a very highly competitive edge in the global nuclear energy sector. There are very few forges with the capacity and technology to make the huge, yet tightly toleranced, components required by modern nuclear plants. You can genuinely count them on the fingers of one hand. Our failure to make the loan investment to Forgemasters means the company must now rely on private investors (whose confidence must surely have been undermined by the Government's inaction) or see its golden opportunity fall to India, China or even to Japan, where there already exists one of the handful of other open die plants of its kind.

Don't forget the knock on effect if the forge loan is not forthcoming - it will affect suppliers of all the ancillary machinery that would go around the plant; expansion of the workforce not just at the company but among the many subcontractors also. Extrapolate this further to the impact the increased wealth would have on local economies, retailing and investment.

I know we must have cuts in public spending, public borrowing and the public sector. I seriously wonder however, how an £80m investment in our futures compares with some public sector spending that regularly consume similar sums.  For example, one could commission 400 consultants to work on projects for a year. One could buy a single jet fighter aircraft. I wonder what local government stationery bills come to?

The Revenue's OGC Buying Solutions reckoned it saved £80m in a single year, just by getting public sector buyers to use its ‘Buying Card' scheme. This hints at inefficiencies, but screams them loud and clear when one considers these savings were on just £500m of transactions - thereby representing an annual waste of 15% just on making purchases.

Alternatively, with £80m the government could buy about half the England football team (the cheap half) or perhaps more wisely, could sign Christiano Ronaldo.

In March 2010, the Times reported UK Contractors Group's outlook for the next few years is Deep public spending cuts will lead to soaring unemployment in the construction industry. At the same time, the UK faces challenging carbon emissions reduction targets between now and 2050, which could be jeopardised by the loss of key skills from the sector explains Tony Sung, chairman of CIBSE Group and technical director at Hywel Davies

The sector faces the twin challenges of riding out the toughest recession in living memory, and delivering new or refurbished buildings which consume less energy and emit less carbon. Much of that carbon is emitted by electrical systems, so the electrical services sector is at the forefront of the drive to improve our building stock.

With the latest revisions to Part L of the Building Regulations coming into force in October 2010, and with the recently introduced Carbon Reduction Commitment in place, developers and building owners will have to allocate more resources to adapting their buildings for future climate changes.

The current cost of adaptation, using some technologies that are not 100% tested and proven, is not considered to offer a fast enough payback, and in many cases is seen as  relatively expensive in offsetting the short-term cost of carbon emissions. Several adaptation technologies such as photovoltaic, on-shore wind farms, hydro and wave power, demand large open spaces, or require planning permissions, or both, which can be hard to obtain. There is a growing conflict between the desire of government to cut carbon emissions and invest in renewable, and the willingness of planners to sanction them.

Whilst some building integrated low or zero carbon technologies are well established, such as solar thermal water heating, photovoltaics, or heat pumps, they may require substantial upfront capital investments. There are only a handful of exemplar projects provided by the Carbon Trust and Energy Saving Trust to demonstrate real life energy and carbon emissions reduction. The Technology Strategy Board is funding a number of further projects in this area to demonstrate how buildings can be adapted to meet the requirements of our anticipated future climate, but these will take time to influence and to stimulate investments by the private sector.

The introduction of the Feed in Tariff provides some incentives to install renewable technology, with the prospect of ongoing revenue to encourage initial capital outlay. The tariff came in in April, and it is too early to see how much of an impact it is having on demand. There are therefore a number of measures which can be expected to stimulate demand for electrical services, but not in the immediate future. Whether this demand will materialise in time to support the sector through the current period of reduced workload remains to be seen.

What we ought to see at this time, with the prospect of steadily increasing demand for energy efficient refurbishment and renewable technologies, is increasing training to meet the emerging demand for these skills. But at present training in the sector is falling, as firms, many of them SMEs, cut back on all non essential spending to conserve cash and protect the business.

One of the measures introduced in response to the Climate Change Act is the Carbon Reduction Commitment Energy Efficiency Scheme, or CRC. This started in April 2010, with the primary objective of helping medium to large size organizations whose total half hourly electricity consumption exceeds 6,000MWh, to cut their energy use and carbon emissions. To enable the For CRC to be a success, Britain needs to up-skill the current M&E workforce (electricians, design and installation engineers) competently to apply, install, test and commission the low zero carbon and smart metering technologies in tens of thousands of existing buildings rather than just for new buildings.

Again, looking at the figures for compliance with the requirement for Energy Performance Certificates, Display Energy Certificates and Air Conditioning Inspections, we should be cautious about the prospects of CRC stimulating a whole new wave of activity in the current economic conditions.

Another area of development is the new amended BS7671:2010, currently issued in draft for public comments. This includes vital changes necessary to maintain technical alignment with Cenelec harmonisation documents. One of the perceived advantages of the technical alignment is it should help British companies to win work in the EU.

Cibse, through its Electrical Services Group, provides electrical services engineers with a network of like minded professionals who are active in all of these areas. Through Group events and through the website, http://www.cibse-electricalservicesgroup.co.uk members can access the collective knowledge and expertise of the group. Additionally, Cibse runs a number of events and training courses for electrical services engineers, and recently launched a new web based learning initiative, to provide training in electrical services (and other building services disciplines) that is flexible and adaptable to user needs. Cibse and the Electrical Contractors' Association recently signed a Memorandum of Understanding, which commits both bodies to work together more closely to help develop and deliver electrical skills and services, to better meet the challenges of climate change.

If we are to meet the carbon emissions reduction targets for 2030 and 2050, we will need to see greater investment, both in new technologies and in skills. Cibse will be looking to work with engineers and employers in the sector to deliver both.