论规范大容量换流变的雷电冲击试验波形参数的重要性

The Necessity and Sufficiency of Specification for Waveform Parameters of Lightning Impulse Test on Large Capacity Converter Transformer

随着500 k V以上的直流输电技术的大力发展,相应的大容量高电压的换流变也不断地研发并应用。作为高电压等级变压器的例行试验之一,雷电冲击试验却因为变压器的容量、尺寸、入口电容的增大而导致电压波形参数往往达不到国家标准的规定。根据对大型换流变的雷电冲击试验波形参数的统计分析,结合国内外雷电冲击波过程的试验研究结果和国际标准的要求,指出现行标准中对换流变雷电冲击试验波形达不到标准要求时,由制造厂和业主协商允许有较大偏差这一规定难以操作,且协商时双方就波前时间和半波峰时间约定的随意性对变压器绝缘强度的考核效果存在影响。因此现阶段在换流变招投标时需明确对雷电冲击试验的规范要求,以修订标准的形式统一规范大容量换流变的雷电冲击试验波形十分必要。

With the rapid development of the DC transmission technology of 500 kV, the correspondingly large-capacity high-voltage converter transformer is also developed and applied. The lightning impulse test, as one of the routine test of high voltage transformer, voltage waveform parameters often fail to meet the provisions of national standards due to the increase of transformer capacity, size, and the entrance capacitance. According to the statistical analysis on lightning impulse test waveform parameters of the large converter transformer, combined with the test results of lightning impulse wave process at home and abroad and the international standard requirements, it is pointed out that when the lightning impulse test waveform of converter transformer cannot meet the requirements of current standard, a larger deviation allowed by the manufacturing factory in consultation with the owners is hard to operate, the arbitrariness of agreed front time and half peak time may impact the assessment effect of the transformer insulation strength. So at this stage the specification requirements of lightning impulse test should be clear in the converter transformer bidding, it is necessary to unified specifying the lightning impulse test of waveform converter transformer capacity in the form of revising standard.