Current Chopping: When interrupting small inductive currents such as transformer excitation currents, circuit breakers tend to clear before the natural current zero is reached. This is because the low-current ionized…
Arc Interruption Methods in Circuit Breakers: The two modes of Arc Interruption Methods in Circuit Breakers are: high resistance interruption, and low resistance or current zero interruption. High Resistance Interruption:…
Arc in Circuit Breaker: Discharge in a.c. circuit breakers, generally in the form of an arc, occurs in two ways. When the contacts are being separated arcing is possible even…
Static Distance Protection Relay: Static Distance Protection Relay are characterized by having two input quantities respectively proportional to the voltage and current at a particular point in the power system,…
Coincidence Type Phase Comparator: The basic concept of phase comparison is simpler in that it is possible to deal with signals of equal strength whose coincidence (or noncoinecidence) is readily…
Static Amplitude Comparator: If the two input signals are S1 and S2 the amplitude comparator gives positive (yes) output only if S2/S1 ≤ K (Fig. (11.1)), S1 is the operating quantity…
Zero Crossing Detector Circuit: Zero Crossing Detector Circuit basically involves the sine to square wave conversion by a level detector circuit followed by a pulse circuit, which consists of one…
Logic Circuit in Static Relay: The concept of Logic Circuit in Static Relay can be better understood by considering the logic operations performed by the devices rather than the actual…
