采用回复电压曲线分解法的变压器等效电路研究

Research on equivalent circuit of transformer by decomposing return voltage curve

针对基于回复电压法的等效电路支路数难以判定的问题,利用回复电压数学模型,分析了回复电压数学表达式与支路参数的关系,提出了回复电压分解法。分离出各极化支路所代表的回复电压子曲线,从而判定等效电路的支路数。通过实例验证表明,利用回复电压分解法能够准确判定等效电路的极化支路数,能更准确地反映变压器绝缘老化状况,且变压器绝缘老化越严重,其回复电压子曲线个数和等效电路的极化支路数越多。

According to the branch number of the equivalent circuit difficult to be determined,this paper uses the mathematical model of return voltage,and analyses the relationship of the recovery voltage’s mathematical expressions between branch’s parameters.Then it presents decomposition method of the return voltage for separating each sub curve of return voltage which polarization branch represented,thus determines the number of the equivalent circuit’s branches.It shows that the number of polarization branches of the equivalent circuit can be determined accurately and the aging condition of the transformer insulation is reflected more accurately by decomposing return voltage curve.Moreover,the more serious of the transformer insulation is,the more numbers of return voltage subcurve and polarization branches of the equivalent circuit are.