Abstract:

With the evolution of smart grids and new energy systems,as well as the widespread deployment of electric vehicle charging infrastructure,the applicability of traditional residual current sensors in complex electrical environments is increasingly limited.A fluxgate type B residual current sensor is designed,which uses a fluxgate current transformer to collect residual current signals and an MCU to identify and judge the signals.According to the requirements of GB/T 22794—2017 standard,the fluxgate type B residual current sensor can detect sinusoidal AC residual current of 1kHz and below 1kHz,smooth DC,pulsating DC residual current generated by two-phase or three-phase rectifier circuits,pulsating DC residual current with hysteresis angles of 0°,90°,and 135°,and composite wave residual current among others.Experimental testing shows that the prototype can effectively detect and identify AC and DC residual current signals,and meet the relevant requirements of national standards in terms of test accuracy and response speed.

Key words: type B residual current sensor, fluxgate current sensor, MCU, waveform recognition