深圳变电站500 kV主变压器直流偏磁现象测试及抑制分析

为明确深圳变电站变压器出现间歇性噪音的成因,解决变压器噪音异常的问题,对深圳站500 kV变压器接地中性点的直流电流进行监测,通过分析表明:该变压器的噪音异常现象是由杂散电流导致的变压器直流偏磁引起。为治理变压器的直流偏磁现象,根据杂散电流入侵变压器接地中性点直流电流的特征,采用电容隔直装置对深圳站的变压器直流偏磁进行抑制;并从深圳站变压器及深圳站片区电网的角度,通过全网监测对比分析隔直装置对深圳站入侵变压器中性点直流电流的抑制效果,以及其对片区电网变压器的影响。结论表明:应根据电网的电气拓扑结构,并基于全网角度,对深圳站500 kV自耦变压器的直流偏磁进行综合优化治理。

Analysis on Test and Suppression of DC Bias of 500 kV Main Transformer in Shenzhen Substation

To confirm causes of intermittent noise of the transformers in Shenzhen substation and solve the problem of abnormal noise,monitoring on DC current of the grounding neutral point of 500 kV transformer in Shenzhen substation was carried out.The analysis indicates abnormal noise of the transformer is caused by DC bias due to stray current.To control DC bias of the transformer,the capacitive blocking device was used to suppress DC bias of the transformer in Shenzhen substation according to characteristics of the neutral point DC current of the transformer caused by the stray current.From the perspectives of the transformers and the power grids in Shenzhen substation,and through the monitoring of the whole network,it is analyzed that the effect of the blocking device on the suppression of the DC current of the neutral point and its influence on the transformers of the grid in the area.The results show that it needs to comprehensively optimize DC bias of the 500 kV auto-transformer in Shenzhen substation according to the electrical topology of the power grid and from the perspective of the whole network.