宽电流范围电能表的计量电路设计

Design of Measurement Circuit of Wide Current Range Electric Power Meter

针对电网中广泛存在的冲击性负荷的准确计量是研究的热点,在仔细研究了该类负荷对计量电路的特殊要求后,提出了一种宽电流范围的计量方案。该计量方案采用了宽量程高精度电流互感器、可编程增益放大器、24位A/D转换器、DSP芯片。经过全面的精度测试,电磁兼容测试与环境试验,表明该设计方案能达到0.2S级电能表的各项准确度要求与可靠性要求。利用功率电能标准源6100A作为参考进行谐波测试,试验结果表明该电能表在谐波输入条件下具有很好的精度。

A hardware design of electric power meter with a wide current range is present. The accurate electric energy measurement of the impact loads is a research focus. Based on the research of impact load＇ s characteristics, a wide range current measurement circuit that includes high accurate current transformers, programmable gain amplifiers, a 24-bit A/D converter, and a DSP was designed. The result of accuracy, EMC and environmental tests shows that the circuit accuracy can achieve 0.2S class and has an excellent reliability. The result of harmonic test that employing 6100A as a power standard source shows that the harmonic electric energy metering accuracy is also good.