智能接地配电系统

为了发挥中性点非有效接地配电网供电可靠性高的优越性,提出了一种通过在变电站配置智能接地装置并在馈线配置具有零序保护功能的配电终端和故障指示器,将配电网升级为智能接地配电系统的方法。发生单相接地时,智能接地装置可以迅速将故障相短暂金属性接地从而可靠熄灭电弧。若为永久性接地故障,随后控制中性点短暂投入中电阻以显著增大接地点上游的零序电流并基于配电终端和故障指示器处配置的零序电流保护可靠地实现单相接地选线、定位和隔离。论述了智能接地配电系统的组成和关键技术,重点论述了通过电阻分级开关应对选相错误并抑制开关操作引起的系统暂态过程的方法。结合实例论证了所建议的方法的可行性和有效性。

Smart grounding power distribution systems

To support neutral non-effectively grounded distribution systems to have high reliability of power supply, this paper puts forward an approach of updating distribution system to smart grounding distribution system, of which we install Smart Grounding Control Unit (SGCU) in substation and configure distribution terminal and fault indicator with zero-sequence protection function. When a single phase to ground fault occurs, the SGCU extinguishes the arc immediately by making the faulted phase metallic grounding for a while. In case of a permanent single phase to ground fault, a resistor is connected to the neutral to significantly increase the zero-sequence current of grounding point up-stream so as to reliably locate and isolate the position of the single phase to ground fault by using zero-sequence current protection installed at distribution terminal and fault indicator. The composition and key technologies of a smart grounding distribution system are described. The innovation of correcting the error of grounding phase identification and reducing the transient process during grounding switching by soft switching control is detailed. An example is given to show the feasibility and effectiveness of the proposed methodology. This project is supported by National Natural Science Foundation of China (No. U1766208)