电子式电流互感器传变特性测试与分析

目前，由于缺乏有效而实用的综合测试平台，开展不同原理电子式电流互感器(ECT)在实际工况下的计量准确度和保护传变特性试验还很少。文中分析了影响ECT准确度和传变特性的关键因素和环节，研制出能够模拟不同运行负荷、环境条件、功率因数、通信异常、一次侧故障等工况下电子式互感器性能测试研究平台，开展了ECT稳态准确度测试、ECT谐波特性与频率混叠测试以及故障下的ECT暂态特性测试。对不同厂家不同原理的ECT测试，发现在稳态误差方面低功率电流互感器测量准确度以及稳定性优于全光纤电流互感器。谐波特性方面随着频率增加，低功率电流互感器的比值误差相对稳定，而罗氏线圈会增大，相位误差两者总体呈现增大趋势；各厂家ECT均存在不同程度频率混叠；全光纤电流互感器能够可靠地传变故障引起的暂态量，而低功率电流互感器在含有直流分量下易饱和，罗氏线圈电流互感器受积分环节影响很大，容易出现超差。

Test and Analysis of Transfer Characteristics of Electronic Current Transformer

At present, due to the lack of an effective and practical integrated test platform, there are few tests on measurement accuracy and protection transfer characteristics of electronic current transformers(ECTs)with different principles under actual working conditions. This paper analyzes the key factors and links that affect the accuracy and transfer characteristics of ECT and develops a platform for simulating the performance of electronic transformers under different operation loads, environmental conditions, power factors, communication anomalies and primary side faults. The ECT steady state accuracy test, the ECT harmonic characteristics and frequency aliasing test and the ECT transient characteristic test under the fault are carried out. Through the test of ECTs of different manufacturers and different principles, it is found that the measurement accuracy and stability of low power current transformer(LPCT)are better than that of all-fiber optic current transformer(FOCT)in terms of steady-state error. With the increase of frequency, the ratio error of LPCT is relatively stable, and the Rogowski coil will increase, and the phase error shows an overall increasing trend. There are varying degrees of frequency aliasing in ECT of various manufacturers. FOCT can reliably transmit transient parameters caused by fault, while LPCT is easy to saturate under DC component, and the Rogowski coil is greatly affected by integral link, which causes serious error.