What protections are required for transformer?
Common Types of Transformer Protection
- Overheating protection.
- Overcurrent protection.
- Differential Protection of Transformer.
- Earth Fault Protection (Restricted)
- Buchholz (Gas Detection) Relay.
- Over-fluxing protection.
How is a transformer thermally protected?
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.
Which relay can be used for transformer protection?
Buchholz relay
Buchholz relay is used for the protection of transformers from the faults occurring inside the transformer. Short circuit faults such as inter-turn faults, incipient winding faults and core faults may occur due to the impulse breakdown of the insulating oil or simply the transformer oil.
What is transformer feeder protection?
Transformer-feeder protection. A transformer-feeder include a transformer directly connected to a transmission line circuit without the intermediation of a HV switchgear. The saving in HV switchgear so achieved is unfortunately lowered by increased complication in the necessary protection.
How can we protect distribution transformer?
Larger distribution transformers are protected by overcurrent and earth-fault protection. Where fault current can be fed from HV and LV sides the overcurrent protection is usually fitted to both sides of the transformer.
What is a feeder protection?
Feeder protection, or more exactly protection for overhead lines and cables, is the most commonly used type of protection. The protection has to ensure that the power grid continues to supply energy. In case of a fault, it must be prevented from spreading to healthy parts of the network.
What is Buchholz protection?
Definition: The Buchholz relay protects the transformer from internal faults. It is the gas actuated relay. The Buchholz relay is placed between the main tank and the conservator. Such type of relay is used in the transformer having the rating higher than 500KVA.
How does a ref relay work?
The earth fault relay must be very sensitive for sensing the fault. The relay is designed for sensing the fault current which is 15% more than that of the rated winding current. Such settings protect a restricted portion of the winding. Hence the name restricted earth fault protection.