Phase Comparison Carrier Protection

Phase Comparison Carrier Protection: The phase comparison pilot-relaying operates on the principle of comparing the phase position of the currents at the two ends of the protected section. The Phase Comparison Carrier Protection of these currents is made over carrier channels. During normal conditions or through faults the currents entering the line at one end, […]

Carrier Pilot Protection

Carrier Pilot Protection and Microwave Pilot Protection: The problem of providing economically an auxiliary channel by means of pilots for long lines directed attention to carrier techniques. In this case the power line itself is used as the channel for carrying information between the two ends of the transmission line. Two different types of communication […]

Pilot Wire Protection Relay

Pilot Wire Protection Relay: In this case the auxiliary Pilot Wire Protection Relay are provided to carry the information signals from one end to the other. Protective systems requiring the use of pilot wires on transmission lines operate on the principle of differential protection. There are basically two forms of differential protection schemes used for […]

Selection of Distance Relay

Selection of Distance Relay: The factors to be considered for the Selection of Distance Relay scheme can be enumerated as follows: Speed of operation. Measuring relay characteristics. Fault coverage. Economic considerations. 1. Speed of Operation: Operating time is of great importance on systems which are liable to become unstable if the fault persists for more […]

Distance Protection by Reactance Relays

Distance Protection by Reactance Relays: Like impedance relays, Distance Protection by Reactance Relays are also amplitude comparators and thus require an additional directional unit. Although the performance of reactance relays on single-fed systems is not unduly affected by fault resistance, there may be occasions in double-fed systems where errors in reach may occur, particularly when […]