不同性质负载下特高压变压器直流偏磁特性分析

Analysis of DC Magnetic Bias Characteristics of UHV Transformer Under Load with Different Properties

特高压变压器受直流偏磁影响后,铁心半波饱和,绕组电压电流波形发生畸变,出现各次谐波分量。对于不同性质的负载,直流偏磁对绕组电流的影响存在较大差异:①不同负载下绕组的电压电流相位差不同,导致绕组电流畸变位置不同;②性质不同的负载在不同谐波分量下的阻抗值不同,导致绕组电流谐波分量及其占比不同。为研究不同性质负载下直流偏磁对特高压变压器的影响,通过三维磁场有限元模型,对特高压变压器的主体变、调压变和补偿变联合仿真,利用场路耦合法求解3台变压器各绕组电压电流实时值,分析了不同性质负载下特高压变压器直流偏磁特性。

The UHV transformer,after the influence of DC magnetic bias,has half wave saturation of core,distortion of voltage and current waveform of winding and occurrence of each harmonic component.For the load with different properties,the influence of DC magnetic bias to winding current has big difference:①The different voltage and current phase of the winding at different loads leads to the different current distortion position of the winding.②The different impedance of load with different properties at different harmonic component leads to the different current harmonic component of winding and its proportion.For studying the influence of DC magnetic bias on UHV transformer at load of different properties,the three-dimensional finite element magnetic field model is used to simulate jointly the main transformer,voltage regulation transformer and compensation transformer of UHV transformer.The field-circuit coupling method is used to solve the real-time voltage and current of each winding of three sets of transformers.The DC magnetic bias characteristics of UHV transformers under loads of different properties are analyzed.