100kA快响应精密冲击分流器研制及特性分析

冲击电流为暂态电流波形,持续时间短且波形不可重复,测量误差影响因素众多难以评估。研制快响应精密冲击分流器,采用同轴管式结构,分析分流器的测量原理及尺寸设计。研究分流器的瞬态响应过程,将输出信号焊接至电阻体外侧,消除趋肤效应的影响。分流器的稳态电阻测量值为0.9697mΩ,杂散电感为32nH,测量额定电流时,电阻温升小于36℃。研制方波电流源测量分流器的动态特性,阶跃响应时间小于4ns,并利用卷积积分的方法计算动态特性引起的峰值和时间参数测量误差。冲击电流波形8/20μs下,进行分流器线性度、稳定性等特性试验。研究冲击电流测量装置的不确定度评定方法,分析不确定度影响因素,峰值参数测量不确定度为0.4%(k=2),时间参数测量不确定度0.8%(k=2)。说明该测量装置可作为标准测量装置用于电流传感器的校准。

Development and Characteristic Analysis of 100 kA Fast Response Precision Impulse Shunt

The impulse current is a transient current waveform,which has a short duration and can not be repeated,so it is difficult to evaluate the influencing factors of measurement errors.A fast response precise impulse shunt is developed.The measuring principle and size design of the shunt are analyzed.The transient response process of the shunt is studied.The output signal is welded to the outside of the resistor to eliminate the skin effect.The steady resistance of the shunt is 0.9697 mΩ_and the stray inductance is 32 nH.When the rated current is measured,the temperature rise of the resistance is less than 36℃.A step current generator is developed to measure the dynamic characteristics of the shunt.The step response time of shunt is less than 4 ns.The convolution integral method is used to calculate the peak value and time parameter measurement error caused by the dynamic characteristics.The linearity,stability of the shunt are tested under 8/20μs.The uncertainty is evaluated by shunt and digital recorder separately.After analyzing the uncertainty components,the measurement uncertainty of the whole system is calculated to be 0.41%(k=2).It shows that the measuring device can be used as a standard measuring device for the calibration of current sensors.