Question

Disadvantages of time graded protection of feeders

Answer 1

Protection of line should have some special features, such as-During fault, the only circuit breaker closest to the fault point should be tripped.If the circuit breaker closest the faulty point, fails to trip the circuit breaker just next to this breaker will trip as back up.The operating time of relay associated with protection of line should be as minimum as possible in order to prevent unnecessary tripping of circuit breakers associated with other healthy parts of power system.