750kV输变电工程中中性点小电抗和接地开关的选取

Selection of Neutral Reactor and Earthing Switches in 750kV Transmission Lines

静电感应和电磁感应是电力系统常见的现象。潜供电流、恢复电压是由于输电线路不同相之间的耦合产生的.而同杆双回线路的检修线路和运行线路之间也存在着电容和电感的耦合。在带有高压并联电抗器的输电线路中,可以通过并联电抗器和中性点小电抗之间的参数配合来降低潜供电流和恢复电压,同杆双回线路之间的耦合由于高压并联电抗器对线路地电容的补偿作用而增强,从而对接地开关的开合产生不利影响。利用电磁暂态计算程序,通过对陕西电网乾县—宝鸡750 kV输变电工程的分析研究,对中性点小电抗和接地开关的选择提出参考意见,确保电网的安全稳定运行。

Electromagnetic induction and electrostatic induction are usually observed in power system. When single phase automatic reclosure is used, secondary arc current and recovery voltage occur due to interphase induction. When one of double circuit transmission lines on same tower is in operation and the other quits for examination and repair, induced voltage and current occur on the latter line which derived from electrostatic and electromagnetic coupling. Four reactor banks are used to reduce secondary arc current and recovery voltage in transmission lines with shunt reactor, and induction is enhanced for the compensalion of shunt reactor between double circuit transmission lines on same tower. Study on Qianxian-Baoji 750 kV transmission lines by EMTP is presented,and selection of neutral reaetor and earthing switches is recommended in this paper.