Power viruses can kill productivity. But what are the six most common types we should be aware of and how should we deal with them? Rob Morris, country manager for Powervar discusses the issues
The dangers of software viruses and their devastating impact on computer systems are well documented. These rogue programs - backdoor Trojans, Worms, etc - enter a system unseen, often incubate in silence, and eventually come to life with results that range from mildly annoying to disastrous.
Electrical disturbances are similar. In fact, they could reasonably be called ‘power viruses' since they, too, are unseen and can cause serious and expensive electronic system failure.
A typical facility experiences as many as 6,000 power viruses or more, every year. Some of these power disturbances are obvious, some less so, many are almost unnoticeable, but they all cause problems and challenges that can seriously damage productivity, from lost data and lock-ups to communications errors and hardware failures. Power viruses are contracted in much the same way as other viruses - they are passed along, often by your system's electrical neighbours. Plug your system into the wall, turn it on, and look out. You've just been exposed to an epidemic, and there are a lot of very sick electrons looking to cause problems. Some of them may take time to cause noticeable damage; others are immediately catastrophic, such as a lightning strike.
How do power viruses affect an electronic system, and what can you do to prevent power viruses in the first place? First it is useful to understand them, so you can tackle the job of immunizing a system against their harmful effects. There are six main power viruses that can invade a system.
Voltage spikes and impulses
This virus is mostly the result of electrical equipment inside a facility. Electrical loads like elevators, motors, relays, induction furnaces and similar devices can cause sudden large increases in voltage inside the electrical system. Conditions outside a facility can be to blame as well.
Switching activities by the electricity utility and lightning strikes can cause transient impulses so intense they literally ‘blow up' sensitive micro-circuitry. This virus is deadly to electronic systems - but not always immediately. Sometimes voltage spikes and impulses are relatively small in amplitude. In these cases, the virus weakens the system components over time leading to deteriorating health and eventual failure. Other times the impulses may be so large that they cause immediate system failure.
Like voltage spikes and impulses, electrical noise is generally created inside the facility by the system's electrical neighbours. Almost every electricity-consuming device contributes its share of electrical contamination. Appliances, photocopiers, printers and electronic lighting ballasts are all noise sources that can cause computers to lock up, lose data, or behave unreliably. Even computers themselves generate electrical noise. It is something of a paradox that our computers often infect other computers with power viruses.
Common mode voltage problems
Traditionally, this power virus has not received much attention. But detection of common mode voltage problems is easier and, as a result, more system problems are being traced to its existence. The condition is characterised by unwanted voltage measured between neutral and ground in the electrical system. In fact, the common mode voltage virus is probably the most serious power virus infecting electronic systems today. It occurs as a result of high impedance safety grounds, neutral conductors shared with other circuits and branch circuit lengths that are excessive.
When the electrical noise virus (already mentioned) appears between the neutral and ground conductors it becomes a common mode virus with the ability to cause lost files, system lock-ups or re-boots, communication errors and ‘no problem found' service calls.
This virus is characterised by abnormal variations in the electrical circuit's nominal operating voltage (120 volts, for example). These variations are generally greater than +10% of nominal voltage and may last for several line cycles or more. Traditionally, this virus has been referred to as the ‘sag' or ‘surge'.
The virus is typically caused by large loads turning on and off and overloaded branch circuits or distribution transformers. In some cases, voltage regulation viruses can be the responsibility of the power utility. If an electronic system requires tightly regulated voltage (most of today's systems don't) the voltage regulation virus is likely to cause system lock-ups and unreliable operation in addition to damaged or destroyed components.
Blackouts are the most visible and easily identifiable of all the power viruses. They have the most obvious cause and effect relationship. One moment power is present - the next moment it's not - and the system is dead in its tracks as a result. The effects of unanticipated power loss are obvious. This is especially true if the system is a network or some other ‘fault intolerant' architecture. Fortunately, in spite of what most UPS manufacturers advertise, blackouts account for comparatively few occurrences of all the power viruses.
Back Door Disturbances
This virus infects your system via a secondary path. Even though they are not an AC power connection, things like serial ports, telephone lines, network cabling and I/O connections can all permit power viruses to invisibly enter a system. This virus causes driver chip failure and communication errors. The back door disturbance virus is often unrecognised. Without treatment, serious damage can occur, and lost productivity can result in substantial financial losses as well.
An ounce of prevention
There is an old adage that ‘an ounce of prevention is worth a pound of cure. Nothing could be closer to the truth when it comes to power viruses. We are familiar with the damage that results from software viruses, and we have all experienced the debilitating and sometimes deadly results of real life viruses like flu pandemics. We go to great lengths to avoid both.
Where our electronic systems are concerned, we have learned to practice safe computing. We back up our data, avoid logging onto questionable websites, bulletin boards and networks, or clicking on emails of unknown origin. We also run anti-virus programs, install firewalls and take other preventative measures on a routine basis.
So why don't we practice safe computing where power viruses are concerned? They have the same potential devastating effects where our systems are concerned. There are five simple devices you can use to prevent the problems outlined above. All five are required for complete immunity.
The magic pill
If there is a magic pill to prevent power viruses, it is clear prevention must be practiced as a ‘system'. What that means is that certain prevention techniques must be used together.
Voltage spikes are addressed with a surge diverter and electrical noise with a noise filter. Each of these by themselves, however, is capable only of weakening or slowing down a virus - not eliminating it.
Isolation transformers eliminate common mode voltage problems. When surge diverters and noise filters are added to the isolation transformer, the resulting ‘system' kills all three viruses.
Uninterruptible power supplies eliminate blackouts, but in spite of many manufacturers' claims, most are not capable of preventing other viruses. Once again, the UPS must be used with the other parts of the system to achieve total virus immunity.
The backdoor disturbance can be addressed several ways. Fibre optic connections are one means of electrically closing the back door, but if ordinary copper wiring is used for communication lines, it may be necessary to employ special surge diversion techniques for these connections.
Luckily, the voltage regulation virus is no longer a serious hazard. Once upon a time, this virus was responsible for many system failures. However, today's systems use switch mode power supplies. This technology was designed as a way of reducing both power supply size and cost while simultaneously increasing electrical efficiency. To achieve these goals, switch mode supplies are designed to consume electrical power differently than their predecessors. These operational differences have created a beneficial by-product where voltage regulation is concerned. As a result, most systems enjoy substantial immunity to the voltage regulation virus. Additional preventative measures (voltage regulators, etc.) are unnecessary.
Power viruses are an appropriate description of the power quality problems that can plague electronic systems. Like other viruses, they are invisible - often announcing their presence only after some initial damage has already been done. Their effects can be a minor annoyance like a lockup or system error, or they can be catastrophic like a blown-up integrated circuit or power supply failure.
Our dependence on sophisticated technology has created an increased awareness regarding the need to safeguard system integrity. Software viruses have led to the introduction of anti-virus programs and data is routinely backed up to prevent loss. Part of this ‘safe computing' lifestyle should be the prevention of power viruses, too.
This is possible only when prevention is systematic. Voltage spikes, electrical noise, and common mode voltage is eliminated by a package that contains an isolation transformer, surge diverter, and noise filter. UPS and data line protection can be added to the system as applications demand.