基于数据融合的组合结构电子式电流互感器设计

目前电子式电流互感器(electroniccurrenttransformer,ECT)大多数采用单传感器开环结构,对每个环节的精度和可靠性的要求都很高,严重限制了ECT整体性能的提高,影响其实用化。介绍了铁心线圈式低功率电流互感器(lowpowercurrenttransformer,LPCT)和印刷电路板(printedcircuitboard,PCB)空芯线圈电流互感器及其数字积分器,在此基础上设计了一种基于PCB空芯线圈和LPCT的组合结构ECT,该结构具有并联和前馈的特点,结合了这2种互感器的优点。采用数据融合算法来实现高精度测量和提高系统可靠性,并提出了辨别LPCT饱和的新方法。实验和仿真结果表明,该ECT可覆盖较大的电流测量范围,达到IEC60044-8标准中关于测量(幅值误差)、保护(复合误差)和暂态响应(峰值)的准确度要求,能够作为多用途ECT使用。

Design of Data Fusion Based Electronic Current Transformer with Combined Structure

At present the open-looped structure with single sensor is applied in the majority of electronic current transformers(ECTs).Because of strict requirements in accuracy and reliability of each link in open-looped structure,the improvement of ECT's whole performance is seriously limited and the practicality of ECTs.After describing the principle of low power current transformer(LPCT)with the structure of iron core coil and that of printed circuit board(PCB)air core coil with digital integrator,a PCB air core coil and LPCT based ECT with combined structure and two sensors is designed,which integrates both advantages of these two kinds of CTs and possesses the features of feed-forward and parallel connection.The data fusion algorithm is used to implement the measurement with high accuracy and improve system reliability.A new method to distinguish the saturation of LPCT is proposed.Experiment and simulation results show that the designed ECT can cover wide current range and achieve the requirements in accuracy for amplitude measurement,compound error of protective relaying and peak value of transient response,so the designed ECT can be used as a versatile device.