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. © 2018 Automation of Electric Power Systems Press.