As mentioned previously, circuit breakers can detect a fault either thermally or magnetically. The magnetic hydraulic circuit breaker is an…

A simple circuit breaker was developed by Edison as early as 1878 when he worked on his electric light circuit.…

The first type of fuse developed was of a melting kind. The word fuse comes from the Latin word to…

ELECTROMECHANICAL RELAYS: Early relay designs utilized actuating forces that were produced by electromagnetic interaction between currents and fluxes, much as…

As can be seen from Fig. 3.8, step distance protection does not offer instantaneous clearing of faults over 100% of…

Distance relays respond to the voltage and current, i.e., the impedance, at the relay location. The impedance per mile is…

Figure 3.5 also shows why the TDOC relay cannot be used without additional help. The closer the fault is to…

The principal application of time delay over current relays (TDOC) is on a radial system where they provide both phase…

The most commonly used protective device in a distribution circuit is the fuse. Fuse characteristics vary considerably from one manufacturer…

The main protection system for a given zone of protection is called the primary protection system. It operates in the…