Retrofit can stop arc flash in less than 8 ms
A new arc protection technology called GE Arc Vault, being developed by GE Consumer & Industrial’s electrical distribution business for delivery in mid-2010, is said to be able to stop an arcing fault in less than eight milliseconds (ms).
Furthermore, GE claims its Arc Vault system can contain an arc fault in less than eight milliseconds with the circuit breaker compartment doors open during operation and maintenance. The incident energy using Arc Vault, in accordance with IEEE 1584 at 24 inches from the arc event, is said to be less than 1.2 cal/cm
Traditional arc resistant switchgear provides protection as long as all circuit breaker compartment doors are closed by exhausting energy away from the area by using a chimney or plenum. Traditional arc resistant switchgear provides less protection when the circuit breaker doors are open as they are during much routine maintenance.
Optimized specifically for low voltage applications, the GE Arc Vault protection system detects an arc flash by sensing both current and light to positively indicate an arc event. When an arc flash event occurs, the system will send a signal to the arc containment device. The arc is then diverted to the containment system in less than one-half cycle or eight milliseconds. At the same time the decision to divert the arc is made, the system will also make a decision to open an upstream circuit breaker. This eliminates the fault condition and will turn off the system in approximately three cycles, at which point the fault will terminate.
The system will reduce the energy released by 63% or more compared to a bolted fault that would occur with a crowbar system, GE said. The energy reduction also lowers the stress on other system components such as transformers, circuit breakers, and equipment and improves the overall system uptime when compared to traditional arc resistant switchgear.
If an arc flash occurs during normal operation and maintenance, in many cases a contractor will be able to make the GE Arc Vault protection system operational again within a working day since fewer replacement parts are required.
A new piece of equipment containing the Arc Vault device can be located within 50 feet of the existing switchgear and the bus can be connected using cable. The detection system is run within the existing switchgear and connected to the new piece of equipment.