- Protection, Automation & Control
- Protection & Control
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Transmission Line Protection
RCS-985U Voltage Injector
The stator earth fault protection with external voltage injection can detect 100% earth faults in the stator winding of generator which is connected with the network via a unit transformer. The auxiliary power supply device RCS-985U can inject low frequency external power source to the generator stator winding side, RCS-985U coordinate with PCS-985, then one set of integral generator stator ground fault protection with 20Hz voltage injection is formed.
The hardware of the RCS-985U is constituted by low-frequency power source, low-frequency filter, converter, voltagedivide resistance and etc. The dimensions of RCS-985U is 266×482.6×281mm (height×width×depth), it can be installed on the spot or in the relay room. RCS-985U has high flexibility and reliability.
Generator neutral point is grounding via a grounding transformer. Through the voltage divider, the RCS-985 protection relay can get UG0. In addition, IG0 is measured via a miniature CT. If a ground fault happens at the generator stator winding, generally the injected low-frequency voltage will decrease and the low-frequency current will increase. If the ground fault location is not near to the neutral point, the zero sequence current will increase significantly.