基于数字恒流技术的B型剩余电流动作特性测试方法的研究

Research on test method of type B residual current operating characteristic based on digital constant current technology

提出一种基于数字恒流技术的B型剩余电流动作特性测试方法,该方法通过任意波形恒流技术产生剩余电流,并记录被测剩余电流保护器的动作时间、动作电流。文中使用直接数字频率合成技术产生任意波形数字信号,并经过数模转换和功率放大电路输出为任意波形剩余电流,采用电流闭环控制策略和数字控制方法,通过电流反馈回路实现恒流输出和参数采集,输出精度可达0. 2%。该方法解决了B型剩余电流保护器动作特性试验中需要复杂剩余电流波形进行测试的问题,并且具有体积小、造价低的优点,为新型剩余电流保护器软硬件研发奠定了基础。

This paper proposes a test method of type B residual current operating characteristic based on digital constant current technology. Arbitrary waveform constant current technique is used to generate the residual current,and this method can record the operating time and operating current of the residual current protector. Arbitrary waveform digital signal is generated by the direct digital synthesizer,thus it can output an arbitrary waveform residual current after the digital-to-analog conversion and power amplifier circuit. In this paper,current closed-loop control strategy and digital control method are used to realize constant current output and parameter acquisition,and the output accuracy is up to 0. 2%. This method solves the problem that a complex residual current waveform needs to be generated in the operation characteristic test of the type B residual current protector. Moreover,this method has the advantages of small size and low cost,which could lay the foundation for the research and development of the new RCD hardware and software.