基于三相4PT接线方式的PT短路故障特征量分析

Analysis of PT Short-circuit Fault Characteristics Based on Three-phase 4PT Wiring Method

针对基于三相4PT(Potential transformer,PT)接线方式的PT短路故障特征量进行分析,并得出变化规律。首先,对4PT接线方式下,二次三相电压、零序电压值进行理论分析;其次,根据PT的设计参数,建立有限元模型,仿真计算绕组相关的电容、电感、电阻等参数,并根据参数构建精细化等值电路模型;再次,基于三相4PT接线方式下,对PT短路故障现象及发生短路故障后各PT电气特征量变化进行详细分析;最后,结合精细化电路模型,通过Matlab建模仿真对PT短路故障后电气特征量变化规律进行验证,证实电气特征量变化规律的正确性。研究结果为PT短路故障在线监测方法提供重要依据,有利于在不退出操作或拆卸的情况下实时准确地监测PT的健康状况。

The short-circuit fault characteristics of the potential transformer(PT)based on the three-phase 4PT connection method are analyzed,and the variation patterns are derived.Firstly,theoretical analysis is conducted on the secondary three-phase voltage and zero sequence voltage values under a typical 4PT wiring method.Secondly,based on the design parameters of PT,a finite element model is established to simulate and calculate the capacitance,inductance,resistance and other parameters related to the winding,and a refined equivalent circuit model is constructed based on the parameters.Once again,based on the three-phase 4PT wiring method,a detailed analysis is conducted on the phenomenon of PT short-circuit faults and the changes in electrical characteristics of each PT after the occurrence of short-circuit faults.Finally,combined with a refined circuit model,the electrical characteristic changes after PT short-circuit fault are verified through Matlab modeling and simulation,confirming the correctness of the electrical characteristic changes.The research results provide an important basis for the online monitoring method of PT short-circuit faults,which is conducive to real-time and accurate monitoring of PT’s health status without exiting the operation or disassembly.