不同负载下变压器超高次谐波传递特性研究

Research on supraharmonics transfer characteristics of transformer with different loads conditions

随着电力系统电力电子化程度的提高,系统中超高次谐波(2~150kHz)问题日益严重。为研究超高频谐波流经变压器的传递特性,在变压器高频谐波电路模型的基础上,基于电路分析原理,推导了变压器谐波传递特性函数,分析了不同负载情况下,变压器谐波电压传递特性;考虑实际工程应用中负载的复杂性,进一步探究了不同功率因数负载下电压传递特性的变化情况;揭示了寄生参数、负载性质和谐振频率与传递特性之间的关系,由于寄生电容的影响,变压器电压传输比不再恒定不变,而是随着频率的增加,会在极点谐振处出现放大现象,在零点谐振处出现趋于零的现象;通过仿真验证了变压器传递特性的准确性;对分析和解决电力系统中超高次谐波问题具有参考价值。

With the improvement of power electronics in power systems,supraharmonics(2~150 k Hz)has become a new power quality problem.To study the transfer characteristics of supraharmonics through transformer,based on the high frequency harmonic circuit model of transformer and the principle of circuit analysis,the transfer characteristics function of transformer is derived.Analyzing the harmonic voltage transfer characteristics of transformer with different load conditions,and considering the load complexity in practical engineering application,the variation rules of voltage transfer characteristics with different power factors is further explored.It also reveals the relationship between the parasitic parameters,the load characteristics resonance frequency and transfer characteristics.Due to the influence of parasitic capacitance,the transformer voltage ratio changes with frequency,and the maximum gain at the pole resonance and the minimum gain at the zero resonance.The simulation verifies the accuracy of the transformer’s transfer characteristics,which has the reference value for the analysis and solution of the supraharmonic problem in the power system.