Design And Implementation Of Intelligent Multi-modesgrounding System

The grounding methods used in power system have three ways, which are neutral grounding, neutral point grounding, neutral point through small resistance grounding and neutral point. But there are obvious advantages and disadvantages of these three kinds of grounding methods. On the basis of analyzing the advantages and disadvantages of these grounding methods, this paper puts forward a kind of intelligent multi-mode grounding system. The installations of arc suppression coil at the transformer neutral point and intelligent automatic control electrical equipment at its ends make the system both has advantages of the resistance grounding and grounding via arc suppression coil. That achieves automatic integration processing on a single-phase ground fault. The system not only ensures the rapid and accurate isolation of the permanent ground fault, but also avoids the long-term existence of the system power frequency overvoltage, which causes the accident to be further expanded. When the permanent grounding fault occurs, resistor automatic input, produce distinct characteristic signal of current to ensure microcomputer protection device can accurately select the fault line, line fault trip correctly and resection, prevent further development of fault; in case of transient grounding fault, by the arc suppression coil compensation capacitor current and reduce the arc reignition, shortening the arc quenching time to ensure normal operation of the power system restoration.The principle, hardware configuration and the controller of The Intelligent Multi-Modes Grounding System was introduced in detail in this paper, and combining with Inner Mongolia Wuhai Electric Power Bureau Wanfeng substation put into operation. The actual application shows that, the system realized instantaneous single-phase grounding fault fast extinguishing the arc, permanent single phase to ground fault trip purpose, greatly improves the safety and reliability of Inner Mongolia Wuhai Electric Power Bureau power distribution system, obtained better economic and social benefits.