Transformer Feeder Protection: Transformer Feeder Protection - In order to supply bulk power from a major switching station, the transformer is sometimes connected directly to the feeder without an HV switchgear at the transformer. Although…
Gas Actuated Relays: Gas Actuated Relays - When a fault occurs inside the transformer tank gas is usually generated, slowly for an incipient fault and violently for heavy faults. Most short circuits developed either by…
Restricted Earth Fault Protection: This type of Restricted Earth Fault Protection is provided to detect earth-faults within the protected zone of the transformer. A CT is fitted in each connection to the protected winding, and…
Star Winding and Delta Winding: Star Winding and Delta Winding - The magnitude of earth-fault current for a given fault position within a winding depends upon the winding connections and the method of neutral earthing.…
Inrush Currents in Transformer: Magnetizing Inrush Currents in Transformer contain pronounced harmonics but the current during internal fault conditions is sinusoidal. Advantage is taken of this fact in the design of the relay. It was…
Percentage Biased Differential Relay: Percentage Biased Differential Relay - In order to avoid undesirable operation on heavy external faults due to CT errors and ratio change as a result of tap changing, a restraining winding…
Differential Protection of Transformers: Differential Protection of Transformers is the most important type of protection used for internal phase-to-phase and phase-to-earth faults and is generally applied to transformers having ratings of 5 MVA and above.…
Transformer Protection Types: Nature of Transformer Faults: Power transformers, being static, totally enclosed and oil immersed develop faults only rarely but the consequences of even a rare fault may be serious, unless the transformer is…