塑壳断路器可靠性试验电源的光纤校准技术研究

Research on the Fiber-optic Calibration Technology for the Reliability Test Power Supply of Molded Case Circuit Breakers

针对塑壳断路器可靠性试验电流的大幅值、短时、交直流混合等特点以及现场复杂工况对大电流标准传感器的严苛要求,提出了基于光纤电流传感技术的塑壳断路器可靠性试验电源现场校准方法。根据光纤电流传感器的闭环检测原理建立了系统的动态模型,分析了阶跃响应和频率响应特性,仿真结果表明:通过调节系统的前向增益及滑动滤波器阶数,传感器的上升时间优于9.09μs,-3 dB带宽可达39.91 kHz,证明了光纤电流传感器对塑壳断路器可靠性试验电流的跟踪响应能力。基于等安匝法对光纤电流传感器进行校准,评定了校准结果的不确定度,结果表明:在2.5~60 kA范围内,传感器的直流、工频电流测量准确度优于0.2%。对塑壳断路器可靠性试验电流进行了现场测试,为塑壳断路器可靠性试验电源的现场校准提供了一条技术途径。

In consideration of the characteristic properties of the reliability test current for the molded case circuit breakers(MCCB)including high value,short time and AC/DC hybrid and the high requirements of field conditions to the reference high current sensors,a field calibration method of reliability test power supply for the MCCB based on the fiber-optic current sensing technology is proposed.The dynamic model of the sensor is established according to the closed-loop signal-detecting principle of the fiber-optic current sensor.The step response and frequency response characteristics of the system are analyzed.The simulation results show that by adjusting the forward gain and sliding filter order of the system,the rise time of the sensor is better than 9.09μs,and the-3 dB bandwidth can reach 39.91 kHz,and prove the tracking response capability of the sensor to the reliability test current of the MCCB.The fiber-optic current sensor is calibrated based on the equal ampere-turn method.The uncertainty of the calibration result is evaluated,and the results show that within the range of 2.5 kA to 60 kA,the measurement accuracy of the sensor's DC and power frequency currents is better than 0.2%.The field test of the reliability test current of the MCCB is performed.The mentioned research provides a technical route for the field calibration of the reliability test power supply of the molded case circuit breaker.