Power Systems
REF relay stands for Restricted Earth Fault Protection. It is an earth fault protection, and it will cover the protection for a particular area or zone. Generally, it is used to detect internal earth fault of a Power Transformer or Reactor. As the earth fault protection is cover for a particular area. It is called … Read more
As the name describes, carrier aided protection operates when the power line carrier is received in the relay and after checking the other fault condition in a transmission line. In distance protection of transmission lines, generally following 4 types of zones are used to protect the line. Zone-I: It will protect 80% of the line … Read more
LBB stands for Local Breaker backup, and it is used as backup protection of the circuit breaker to isolate the fault in case the circuit breaker is failed to trip. It is also called Breaker failure relay (BFR) or 50BF. ANSI code of LBB protection is 50Z. LBB protection plays important role in power system … Read more
SOTF protection stands for Switch On To Fault. If any fault is persisting in the transmission line during energization of Circuit Breaker or fault happens within 20 ms from the CB closing, the SOTF protection will activate and it will trip the Circuit Breaker immediately to isolate the fault. Why SOTF Protection? We know that … Read more
Auto recloser function is used for transmission line protection system to avoid tripping during transient fault of the line. The function is available in the distance protection relay however separate auto recloser relay is also available for using the function. Auto Recloser Relay Function: We know that the distance protection relay is used to protect … Read more
STUB Protection is simple overcurrent protection it is used to protect the power system transmission line when the line isolator is in open condition. STUB protection is mainly required in one and half breaker busbar schemes. In one and half breaker scheme, 2 nos. lines are connected to 2nos. Bus through the 3 nos. Circuit … Read more