基于电子式互感器的数字保护接口技术研究

在新一代数字化变电站自动化系统中，电子式互感器取代了传统的电磁式互感器，由合并单元与保护装置接口，完全改变了以往的数据采集方式，由此带来了保护装置设计中的新问题。文章研究了基于电子式互感器输出的信号处理及调理技术，采用PLL(phase-locked loop)同步锁相技术、基于插值的采样值计算方法，根据精确的频率测量算法实时调整与电子式互感器进行数字接口的采样频率，理论分析和工程试验结果表明，该方法可有效地对电子式互感器的数据按要求进行高精度的同步采集，可广泛应用于各类数字保护的开发和试验中。

Research on Interfacing Technology for Digital Protection Based on ECT/EVT

Electronic voltage transducers(EVTs) and electronic current transducers(ECTs) are substituting traditional electromagnetic potential transformers and current transformers.The EVTs and ECTs are interfaced by merging unit(MU) with protection device,so former data acquisition modes are thoroughly changed and new problems are brought into the design of protection devices.After the research on signal processing and conditioning based on EVT and ECT output,by means of phase locked loop(PLL) synchronous phase locked technique and interpolation based sampling calculation method,according to accurate frequency measurement algorithm the real-time adjustment of sampling frequency for digital interfacing with electronic transducers is realized.The results from theoretical analysis and engineering tests show that the proposed method can effectively implement accurate synchronous data acquisition from EVTs and ECTs as required.The proposed method can be applied in the developments and tests of various kinds of digital protection devices.