Guest blogger Steve Scala talks about a new technology that is helping improve the safety of electrical apparatus
Arc flashes are a serious concern in the electrical industry. Arc flashes are a result of a fault in an electrical system where a high voltage shorts rapidly to ground. The resulting arc plasma can exceed temperatures of 35,000 °F and the energy released can vaporize copper conductors, melt steel barriers, and create an explosion as the plasma expands outwards with extreme force. Workers and operators in the vicinity of these arc faults are exposed to explosive, high temperature forces which can lead to serious injury or death.
The most recent development in arc flash mitigation from ABB is the pairing of the REA Arc Flash Mitigation System with the Ultra fast Earthing Switch (UFES). The basis for operation of the REA is to sense an arc fault using light and current and quickly trip an upstream electrically operated device in order to clear the fault.
The pairing of the REA with UFES works well in applications where an upstream breaker or other device is either:
a) too far away to make a copper or fiber connection
b) shared by other circuits and too critical to trip
c) not able to be modified to be electrically operated or the electrical operation would exceed 5 cycles (as in a load break switch, contactor)
The REA and UFES pairing provides rapid grounding of the circuit to reduce the incident energy level to near zero, regardless of upstream tripping time and low voltage fault availability.
One attractive pairing of these products can also protect transformers from damage in the event of an arc fault in a low voltage switchgear. The key is to connect the UFES to the line side, anywhere in the path between the fuse and transformer primary terminals. The REA should be located in the gear at the low voltage level. This set-up typically provides grounding of the primary circuit in 4 milliseconds with no physical or mechanical stresses on the transformer.
The engineers in our Medium Voltage Service team can help choose the right set-up for your application. There are installations throughout the U.S. with more being added every day.
Please call us at our Customer Service Center at 1 800 435 7365 or 1 800 HELP 365 to find out how the REA and UFES can work for you.
To learn more, watch this video:
Steve Scala works as a Business Development Manager for Protection and Controls as part of ABB Medium Voltage Service. He works out of Coral Springs, FL