Distance Protection: Both time-graded and pilot-wire system are not suitable for the protection of very long high voltage transmission lines. The former gives an unduly long time delay in fault clearance at the generating station…
Differential Pilot Wire Protection: The Differential Pilot Wire Protection is based on the principle that under normal conditions, the current entering one end of a line is equal to that leaving the other end. As…
Time Graded Overcurrent Protection: In this scheme of Time Graded Overcurrent Protection, time discrimination is incorporated. In other words, the time setting of relays is so graded that in the event of fault, the smallest…
Busbar Protection: Busbars and lines are important elements of electric power system and require the immediate attention of protection engineers for safeguards against the possible faults occurring on them. The methods used for the protection…
Circulating Current Scheme for Transformer Protection: Merz-Price Circulating Current Scheme for Transformer Protection is commonly used for the protection of power transformers against earth and phase faults. The system as applied to transformers is fundamentally the…
Earth Fault Protection or Leakage Protection: An Earth Fault Protection usually involves a partial breakdown of winding insulation to earth. The resulting leakage current is considerably less than the short-circuit current, The Earth Fault Protection…
Buchholz Relay: Buchholz Relay is a gas-actuated relay installed in oil immersed transformers for protection against all kinds of faults. Named after its inventor, Buchholz, it is used to give an alarm in case of incipient (i.e. slow-developing)…
Protection of Transformers: Transformers are static devices, totally enclosed and generally oil immersed. Therefore, chances of faults occurring on them are very rare. However, the consequences of even a rare fault may be very serious…
Balanced Earth Fault Protection: In small-size alternators, the neutral ends of the three-phase windings are often connected internally to a single terminal. Therefore, it is not possible to use Merz-Price circulating current principle described above…
Differential Protection of Alternators: The most common system used for the protection of stator winding faults employs circulating-current principle (Refer back to Art. 21.18). In this scheme of Differential Protection of Alternators, currents at the…
