Arcing faults can be quickly detected and cleared using the Falcon Arc Detection System from CEE Relays. Clearing arcing faults more quickly reduces the incident energy of the fault. The incident energy at each busbar and required personal protective equipment (PPE) can be calculated using the Arc Flash Evaluation module of the Power*Tools for Windows (PTW) power system analysis software, helping engineers modify protection settings and the network configuration to reduce the incident energy. Reducing the incident energy reduces the risk to personnel and the expensive downtime due to the damage caused by arcing faults.
A full understanding of arcing faults, and their speedy elimination, is essential to the safe operation of a power system. A failure to do so can lead to injury to operating personnel, potential fines, lost productivity, and increased insurance costs.
Arcing faults occur when the short-circuit current passes through the vapour between conductors. These high-temperature arcs (up to 35,000°F) can cause fatal burns, even when standing several feet from the arc. The electrical arcs also shower droplets of molten material into the surrounding area, causing further hazard (copper expands up to 67,000 times when vaporising). The arcing fault current is smaller than the traditional bolted fault current because the vapour acts as impedance between the conducting materials, sometimes making traditional protective devices less effective at isolating the fault.
Wearing insufficient PPE is dangerous for obvious reasons, but wearing too much clothing is dangerous due to reduced mobility and visibility. Electrical arc burns account for a large percentage of electrical injuries.
Advantages of the Falcon Arc Detection System include:
• Arcing faults are detected in less than 1ms, significantly reducing the expensive downtime associated with damage caused to electrical equipment and the risk to personnel.
• The arc detectors can easily be retrofitted to existing switchgear.
• Optical tripping signalling is fast and distortion free.
• Reducing the incident energy reduces the level of PPE required, meaning that less-cumbersome PPE may be worn, reducing the risk of accidents.
• Programmable tripping logic makes it possible to use the Falcon system in switchgear with many different circuits.
• The installation, operation and maintenance personnel don’t need any specialist training.
• The main unit specifies the exact sensor that detected the fault, reducing the recovery time after an arcing fault.
• The Falcon Lite system , which is suitable for LV networks, is available.
Features of the Arc Flash Evaluation PTW module include:
• Incident energies and arc flash boundaries are calculated to IEEE 1584, NFPA 70E, or NESC 2007.
• PPE clothing requirements are specified in a user-defined, pre-populated, clothing library.
• Arcing fault currents are automatically calculated from the solid 3-phase fault currents calculated using DAPPER PTW .
• Protection operating times are calculated from the protection trip-curves plotted using CAPTOR PTW .
• Alternative system designs can be easily evaluated and compared using PTW’s powerful Scenario Manager. The scenario with the lowest incident energy will minimise the damage, risks and costs caused by arcing faults.
• Arc Flash labels (produced to comply with NEC 110.16) and work permits can be automatically generated using standard, or user-defined, formats.
• A low-cost version ( Arc Calc ) is available for smaller networks.
For more information visit www.ceerelays.co.uk or call us on +44 1753 576477.
