Research On Substation Relaying Protection Secondary System Grounding Technology

With the growing popularity of substation automation, relaying protection devices gradually realize computer and integration. Electromagnetic environment around are increasingly high requirements. In a substation, substation primary equipment is numerous, high voltage level primary device in the normal operation and failure both will produce interference to substation secondary system.Firstly, this paper analyzed and classified the common interference sources and interference transmission way based on the previous research material, and analyzed the producing mechanism and transmission way of three kinds of the most influential interference sources for substation secondary system, including substation primary equipment being struck by lightning, primary device making a grounding circuit and breaker or isolating switch opening and closing operation. A substation secondary ground system is an effective way to reduce secondary system interference deduced from the theoretical level. Then combined with the actual construction situation, this paper proposed laid principle of substation secondary grounding grid system. From substation secondary system, outdoor terminal box, indoor protection cabinet, secondary cable related equipment and a.c secondary circuit five aspects this paper put forward principles must be followed and construction methods in the grounding grid laying. Finally, this paper analyzed the protection malfunction case of a500kV substation to verify the validity of this principle...