A Further Research And Improvement Based On S's Signal Injection For Single Phase To Ground Faults Location In Distribution Network

Based on S's Signal Injection Method, two problems of it have been proposed: when the frequency is 220Hz, distributed capacitance of line's influence on location is very obvious when it happens high resistance(10kΩ) faults; Signal is injected from Secondary of PT, its energy is restricted by PT's capacity. Based on these, three aspects of work have been done in this paper: S's Signal Injection Method has been improved, the circuit distributary of distributed capacitance has been decreased by reducing work frequency, and 60Hz signal generator is developed; location adopts off-line way, and the point of injection is changed in Exit of line; low- frequency signal detector is designed and realized.In the end of this paper, the hardware circuit is simulated by Simulink, the result have shown that the developed signal generator is practical and useful. Experiment result in BaoDing GuCheng Substation has shown that, it can prolong the location distance, and it can expand the application scope of S's Signal Injection Method.