Assessment of Arc Flash Detection System in Distribution Network

Abstract

The consequences from an arc flash hazard is very severe. As the temperature of an arc can reach four times the temperature of the Sun’s surface and occurs very fast, one can get skin burn up to four degree and damaged inner abdominal, permanent blind, hearing impairment and other physical injuries. Arc flash inside breaker compartment can cause breaker explosive blast and destroy costly equipment. To mitigate arc flash hazard is to reduce the fault clearing time. The longer the arc fault is in the system, the more damage would take place, while the damage could be insignificant for a very fast fault clearing time. This paper is intended to utilize IEC61850 communication protocol in current arc protection relaying in which the protocol can run over TCP/IP networks or substation LANs using high speed switched Ethernet to obtain response times below four milliseconds. Unshielded fiber optic connected to a relay at outgoing panel is used to detect arc flash in the busbar, cable and breaker compartments. Trip signal issued from the relay will be transferred to a relay at incomer panel using IEC61850 which will trip its breaker and isolate the whole busbar from the fault. This method reduces transfer tripping time as compared to conventional hard wire method and minimize the material damage, increases operating personnel safety and ensure smooth power restoration. The concept of having built-in arc protection in Over Current Earth Fault (OCEF) relay gives economic value to customer where one relay can serve two functions at one time.