高压引线杂散电容对CVT误差特性影响研究

Study on the influence of distributed conductive capacitance of test wire on CVT error characteristics

在进行电容式电压互感器(CVT)现场误差试验时,需要在CVT上挂接高压引线,挂接的高压引线与CVT本体之间会引入杂散电容,杂散电容叠加到CVT本体上,造成CVT分压比偏离正常值,从而影响试验误差值。该文建立了高压引线与CVT本体之间的杂散电容计算模型,定量分析计算了高压引线随挂接角度变化给被试CVT引入的杂散电容,得出其对误差数据的的定量影响,并在现场试验中进行了验证。根据影响程度给出误差试验时高压引线的建议角度,对指导CVT现场误差试验,保证试验数据准确具有较大意义。

During the field error test of the capacitive voltage transformer(CVT),high voltage leads need to be connected to the CVT.Stray capacitance will be introduced between the connected high voltage leads and the CVT body.The CVT partial pressure ratio deviates from the normal value,thereby affecting the test error value.A stray capacitance calculation model between the high-voltage lead and the body of the CVT is established in this paper.The stray capacitance introduced by the high-voltage lead to the CVT of the subject as a function of the mounting angle is quantitatively calculated.Validated in field tests.According to the degree of influence,the suggested angle of the high-voltage lead during the error test is of great significance to guide the CVT field error test and ensure the accuracy of the test data.