基于新型换流变压器偏磁特性仿真研究

摘要

研究变电站优化供电问题,高压直流输电中交直流输电线路并行时换流变压器存在直流偏磁问题,直流偏磁产生的谐波严重干扰到电网的安全运行.分析了新型换流变压器在直流偏磁下的励磁电流畸变特性和谐波特性,为了提高电力系统安全保护性能,提出采用感应滤波技术来抑制直流偏磁谐波的新方法,根据新型换流变压器的参数建立交直流输电线路系统模型,对谐波特性进行仿真,仿真证明了感应滤波技术在交直流输电线路平行架设时对直流偏磁产生的谐波污染具有良好的隔离屏蔽效果,可为设计提供依据.%AC/DC parallel transmission lines lead to DC bias of converter transformer in the HVDC transmission.The harmonic caused by DC bias disturbs thesafe operation of electrical network.This paper analyzes the distorting and harmonic characteristics of excitation current of new-type converter transformer under DC bias, and proposes a new inductive filtering technology to restrain the harmonic of DC bias.According to the rated parameters, the system model AC/DC transmission lines is established, and harmonic characteristic is compared with traditional converter transformer.The result shows that the inductive filtering technology has good suppression effect on harmonic pollution of DC bias caused by parallel AC/DC transmission line.