Protection of Alternators: The generating units, especially the larger ones, are relatively few in number and higher in individual cost than most other equipment’s. Therefore, it is desirable and necessary to provide Protection of Alternators to cover the wide range of … (Read More)

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 two ends of the protected section … (Read More)

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 because there are no facilities for … (Read More)

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 unless the transformer is quickly disconnected … (Read More)

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) faults in the transformer and to … (Read More)

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 may continue for a long time … (Read More)

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 Stine as that for generators but … (Read More)