2抑制装置参数计算与控制-电测与仪表.DOCVIP

基于电位补偿的变压器直流偏磁抑制装置 尹忠东，王帅，王书瑶 （华北电力大学新能源电力系统国家重点实验室 ，北京 102206） 摘要：。比较了现有的抑制变压器直流偏磁的主要方法，提出了基于电位补偿的变压器直流偏磁抑制装置拓扑，而后PSCAD/EMTDC对拓扑进行仿真，并制作样机，在进行了模拟验证了有效和性。 关键词：变压器；直流偏磁；电位补偿；抑制 中图分类号：TM933 文献标识码：B 文章编号：1001-1390（201）00-0000-00 A restrain device for the transformer DC magnetic bias based on electric potential compensation Yin Zhongdong, Wang Shuai, Wang Shuyao (State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Chang ping 102206, Beijing, China) Abstract: The high development of HVDC makes a contribution to the transformer DC magnetic bias, which does harm to the normal operation of ac power grid system and the transformer itself seriously. Therefore, it is necessary to restrain the dc bias in the neutral line. The common methods used to restrain DC magnetic bias are connecting a resistor or a capacitor in the neutral line, or reverse current injection, electric potential compensation and so on. This paper proposed a suppression method based on DC electric potential compensation after comparing the traditional methods. In addition, and presented a novel topology of a device based on the method above. What is more, the topology was simulated with PSCAD/ EMTDC, and we conduct experiments in the lab, whose results are in accordance with each other, which proves that the topology has a satisfying performance on restraining the neutral current. Keywords: transformer, DC magnetic bias, electric potential compensation, restrain device 0　引 言 地磁风暴和高压直流输电单极大地运行时，产生的地电流可能会使地面上的交流变压器发生直流偏磁。尤其是后者，随着全国范围内直流输电工程的大量投入运行，发生直流偏磁的交流变压器也越来越多[1-4]。 交流变压器发生直流偏磁时，会产生大量谐波，噪声以及热损耗，甚至导致变压器损坏，严重影响电网安全运行[5-7]。因此对变压器直流偏磁抑制装置的研究具有重要的实际应用价值。 目前，国内关于抑制直流偏磁的方法包括变压器中性点串小电阻法、电容隔直法、直流电流反向注入法、电位补偿法、输电线串电容法、改善电网中的直流分布、降低变压器的运行工作点[6-8]等，应用最多的是前四种方法。 四种方法中，中性点串小电阻法具有电路结构简单的优点，但不能彻底的抑制中性线电流，且小电阻的串入会使中性点发生偏移，对继电保护产生影响；电容隔直法具有相似的问题；反向电流注入法通用性好，且不会使中性点发生偏移，但是装置结构最复杂，前期投资以及后期维护成本都极高；电位补偿法能彻底抑制中性点直流电流，其结构复杂