800kV特高压换流变压器现场局部放电试验

Field partial-discharge test for 800 kV UHVDC converter transformer

局放试验是检测变压器内部是否存在故障的有效手段之一。在云南—广东±800 kV特高压直流输电工程中进行的800 kV特高压换流变压器的现场局放交接试验,为世界范围首次在工程现场进行的电压等级最高的变电站局放试验。介绍了标准、程序和过程,总结分析试验过程中出现的电感补偿电流不足、电缆过热和低端换流阀和换流变压器运行所带来的干扰等问题,提出解决方法,并在试验过程中予以了验证。同时分析现场局放试验对保证换流变压器安装质量和运行安全的优点和缺点。

The partial discharge （PD） test is one of the effective methods to detect fault in transformer. The field PD test for 800 kV UHV converter transformer conducted in Yunnan-Guangdong - 800 kV UHVDC project is the first PD test for UHV substation converter transformer on the world＇s highest voltage level. The standards, procedures and process of the PD test are presented. The problems that appear in PD tests are analyzed, including under-compensated inductive current, over-heating electric cable, interference effect caused by the operation of low-voltage converter transformers and thyristor valves. The solutions are validated in the test process. The advantages and disadvantages of field PD test to ensure the installation quality and operation safety of converter transformer are also analyzed.