What is alternator protection?

Any internal fault inside the stator winding is cleared by mainly differential protection scheme of the generator or alternator. To ensure that the relay does not operate for the faults external to the operated zone of the protection scheme, a stabilizing resistor is fitted in series with the relay operating oil.

What is the protection of transformer?

The protection of a transformer against the overloads is performed by a dedicated protection usually called thermal overload relay. This type of protection simulates the temperature of the transformer’s windings. The simulation is based on the measure of the current and on the thermal time constant of the transformer.

What are the different types of alternator protection?

With increasing size and voltage of the generator, this form of protection is becoming essential for all large generating units.

• Stator Earth Fault Protection.
• Rotor Earth Fault Protection.
• Unbalanced Stator Loading Protection.
• Protection against Stator Overheating.
• Low Vacuum Protection.

What type of backup protection is used for alternator?

What type of back up protection is used for alternators? IDMT relay.

Which relay is used for transformer protection?

Buchholz Relay
The Buchholz Relay for Inter-turn Fault Protection: It should be noted that Inter-turn faults are also known as incipient faults which means that such faults are not much dangerous in the beginning but gradually progress into extreme faults overtime. Therefore, a buchholz relay is employed to protect from these faults.

How many types of protection are there?

There are two types of overload protection: instantaneous overcurrent (IOC) and time overcurrent (TOC). Instantaneous overcurrent requires that the current exceeds a predetermined level for the circuit breaker to operate. Time overcurrent protection operates based on a current vs time curve.

What are transformer relays?

Transformer Relays provide primary protection, control, and back-up protection of transformers, including current differential, restricted ground differential, and overcurrent protection.

How do you protect a transformer from faults?

Overheating protection is provided for transformers by placing a thermal-sensing element in the transformer tank. Overcurrent relays are used as a backup protection with time delay higher than that for the main protection. Restricted earth fault protection is utilized for Y-connected windings.

Why do we need transformer protection?

The primary objective of the Transformer Protection is to detect internal faults in the transformer with a high degree of sensitivity and cause subsequent de-energisation and, at the same time be immune to faults external to the transformer i.e. through faults.