基于串联电阻的特高压变压器空载直流偏磁计算

利用变压器时域场路耦合模型,计算单相特高压自耦变压器的空载直流偏磁特性。通过增加串联电阻值,提高计算电流中直流分量的计算精度。根据不同串联电阻值时的计算分析,得到串联电阻的取值范围。增加串联电阻,改变电路结构,通过电压补偿的迭代仿真计算,可有效消除增大串联电阻值导致的电流计算偏差。求解瞬态电流的四阶龙格库塔法,一次斜率计算,对应一次磁场求解电感计算。适当减小步长,有利于提高计算电流中直流分量的计算精度,降低串联电阻的取值。在稳定性和精确性分析的基础上,进行特高压变压器不同直流偏磁电流下的空载直流偏磁仿真计算,获得励磁电流波形,并分析了电流的谐波成分。

DC-Bias Calculation for UHV Transformer in No-Load by Series Resistance

The DC-biased characteristics of UHV transformer are solved based on the time-domain field-circuit coupled model.The accuracy of the DC component about the calculated current is improved by increasing the series resistance.According to the calculations of different series resistance,the range of series resistance is deserved.The series resistance changes the circuit configuration of UHV transformer,while the voltage compensation effectively eliminates the current calculation error arising from the series resistance.The transient current is solved by the fourth Runge-Kutta,where a slope calculation corresponds to an inductance calculation.Reducing the time step appropriate can improve the calculation accuracy of current DC component and reduce the series resistance.Based on the analysis of the stability and accuracy,the precise excitation current waveforms are obtained and harmonic components are analyzed through DC bias calculation for UHV transformer in no-load with different bias currents.