What Are the Main Types of Protection Relays?

The relays are used to protect the electrical equipment from damage in case of the fault. The protection relays are used to protect electrical equipment. The following types of relays are used for electrical equipment.

 

Feeder protection Relays:

 

Overcurrent(IDMT, definite and Instantaneous current/time characteristics)

Earth Fault Relay

Under voltage relay

Fuse Failure Relay

Transformer Protection Relays:

 

Gas operated Relay for main tank and tap changer

Overcurrent(O/C) Relay

Earth Fault Relay

Restricted Earth fault (REF) Relay

Oil temperature/winding temperature relay

Pressure operated relay

Over fluxing Relay

Differential Relay

Motor Protection Relays:

 

Motor Protection Relay: The relay has the Overload, negative(I2) phase seq., Earth fault, unbalance and undervoltage protections.

Differential relay for a large rating motors

Generator Protection Relays:

 

Overvoltage

Short circuit

Thermal overload

Negative phase sequence(NPS)relay

Differential protection

Under/Over frequency detection relay

Earth Fault Relay

Under voltage

Rotor earth fault relay

Under excitation relay

Synchronization system Relay:

 

Under/Over Voltage

Reverse power relay

Low Forward power Relay

Check Syncronizing Relay

Directional Overcurrent relay

df/dt Relay