多直流接地系统单极运行对沪西特高压变电站直流偏磁的影响  

Impact of Multiple HVDC System Monopolar Operation on DC Magnetic Biasing in West Shanghai UHVAC Substation

作　　者：段炼[1] 江安烽[1] 傅正财[1] 魏本刚[2] 

机构地区：[1]电力传输与功率变换控制教育部重点实验室(上海交通大学),上海市徐汇区200030 [2]上海市电力公司上海电力科学研究院,上海市杨浦区200437

出　　处：《电网技术》2014年第1期132-137,共6页Power System Technology

基　　金：国家电网公司皖电东送工程单项研究专题-超;特高压直流输电系统的运行对特高压交流系统的影响研究~~

摘　　要：研究了上海周边7条超高压与特高压直流系统中有条或多条线路单极运行时,上海沪西等特高压变电站和上海500 kV电网的直流偏磁情况。电磁仿真计算各交流变电站的地电位分布与中性点偏磁电流,结果表明:多条直流线路单极运行时条线路上的电流不会通过其他线路回流,特高压变电站的直流电流在多条线路同时单极运行时的数值等于单条线路单极运行时的代数和,向家坝—上海、锦屏—苏南、三峡—上海这3条线路单极运行时对沪西变电站的影响大,使特高压变压器中性点偏磁电流超过5 A,约2.4?的变压器中性点串联电阻可较好地抑制沪西特高压变电站的直流偏磁电流。The DC magnetic biasing in Shanghai UHVAC substations and that in Shanghai 500 kV power network are researched when one or more in seven EHVDC and UHVDC power transmission lines around Shanghai are operated in monopole operation mode. Results of electromagnetic simulation on ground potential distributions in AC substations and biasing currents through neutral points show that when multi DC transmission lines are operated in monopole operation mode, the current of one line will not backflow via other lines; when multi DC lines are operated in monopole mode simultaneously, the value of DC current biasing in UHVAC substations is equal to algebraic sum of the DC current biasing of each DC line solely operated in monopole mode; the most serious impact on the West Shanghai UHVAC substation is caused by monopole operation mode of three EHVDC and UHVDC lines, namely the EHVDC transmission line from Three Gorges to Shanghai, the UHVDC transmission line from Xiangjiaba to Shanghai and the UHVDC transmission line from Jinping to Suzhou, and it makes the DC biasing current at neutral point exceeding over 5 A; the transformer neutral point series-resistor with the value about 2.4 ohm can suppress the DC magnetic biasing current in West Shanghai UHVAC substation better.

关 键 词：特高压交流变电站 直流偏磁 超 特高压直流线 路 多回直流线路 串联电阻 

分 类 号：TM721[电气工程—电力系统及自动化]