基于超低频任意波形信号源进行保护用电流互感器励磁特性试验新方法

A New V-A Characteristic Test Method of Protection Current Transformer Based on Super Low Frequency Arbitrary Waveform Signal Source

目前保护用电流互感器励磁特性试验的工频试验方法和低频正弦波试验方法都存在着一定不足之处,针对上述存在的问题,参考Lucas模型建立了一种超低频任意波形信号源对保护用电流互感器进行励磁特性试验的分析计算方法。该方法把电流互感器的励磁电流分离为涡流损耗电流和磁滞损耗电流两个部分,测量互感器铁心损耗、基本磁化曲线和极限磁滞回线等相关参数,充分考虑直流电阻上产生电压降的影响,通过计算得出工频下励磁特性数据。本文打破传统运用工频和低频正弦波进行励磁特性试验的约束,充分考虑电流互感器的铁心饱和、磁滞和直阻等因素影响,建立一种任意波形、超低频率信号励磁的模型和计算方法,大量试验对比验证说明了此方法是准确和可靠的。

At present,both the power-frequency test method and the low-frequency sine-wave test method for the excitation characteristic test of the current transformer for protection have some shortcomings.Aiming at these existing problems,this paper establishes an analysis and calculation method of excitation characteristic test for protection current transformer with ultra-low frequency arbitrary waveform signal source according to the Lucas model.In this method,the excitation current of current transformer is separated into eddy loss current and hysteresis loss current,and the related parameters are measured,such as transformer core loss,basic magnetization curve and limit hysteresis loop.The influence of voltage drop on DC resistance is fully considered,and the excitation characteristic data under power frequency are obtained by calculation.In this paper,a breakthrough have been made in the restriction of excitation characteristic test by the traditional way of using power frequency and low frequency sine wave,we fully consider the influence of the core saturation,hysteresis and direct resistance of current transformer,and establish a model and a calculation method for arbitrary waveform.Various experiments and comparisons proves that the method proposed in this paper is accurate and reliable.