Research And Implementation of High Precision Full Range Analog Acquisition System Based on Zero Flux Current Transformer

The new generation substation has a special demand for high-precision measurement and high-performance power quality of fiscal metering units, compared with the traditional fiscal metering units, the detection current is smaller and the dynamic measurement range is wider. In order to solve the above problems, a scheme of using zero flux current transformer to collect current to ensure the effective value and phase accuracy of small current, using high-precision ADC chip in hardware, multistage current acquisition and multi-point calibration in software is proposed, complete large dynamic range current acquisition, to design method of substation fiscal metering units to realize the functions of electricity metering and power quality. Through the data acquisition of two hardware design schemes, the scheme of zero flux current transformer + multi-stage acquisition is superior to the scheme of traditional current transformer + single-stage acquisition, meetting the technology needs of a new generation of substation fiscal metering units.