Most differential protection relays are current differential relays in which vector difference between the current entering the winding and current leaving the winding is used for sensing and relay operation.
Differential protection principle is used I the following applications.
§ Protection of the generator, protection of generator transformer unit.
§ Protection of transformer.
§ Protection of feeder (transmission line) by pilot wire differential protection.
§ Protection of transmission line by phase comparison carrier current protection.
§ Protection of large motor.
§ Bus-zone protection.
§ Protection of the generator, protection of generator transformer unit.
§ Protection of transformer.
§ Protection of feeder (transmission line) by pilot wire differential protection.
§ Protection of transmission line by phase comparison carrier current protection.
§ Protection of large motor.
§ Bus-zone protection.