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. As shown in the picture, when the fault … Read more
RTCC stands for Remote Tap Changer Control. It is used to control the transformer output voltage by controlling the OLTC unit of the transformer. As we know the OLTC (On Load Tap Changer) is responsible to change the transformer output voltage. OLTC controls the winding tap position of the Transformer and it resulted in the … 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
TNC switch stands for Trip Neutral Close switch. As its name, it is a three-position switch. TNC switch uses to control the Circuit Breaker of the electrical system. The trip position is used to trip the circuit breaker, the close position use for closing the circuit breaker, and the neutral position is the default position … 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 uses a simple overcurrent protection system to protect the transmission line when the line isolator remains open. Stub protection works mainly in a one-and-a-half breaker busbar scheme. In this scheme, two lines connect to two buses through three circuit breakers, as shown in the diagram. When one line shuts down or switches off, … Read more