采用等安匝合成电源的电流互感器谐波特性测量方法

A Measurement Method of Current Transformers' Harmonic Characteristics by Using Equal Ampere-turns Synthetic Power

为解决电流互感器(current transformer,CT)谐波特性测量所面临的基波电流大、谐波电流的成分及幅值可控、溯源难度大等问题,提出了采用等安匝合成电源实现的CT谐波特性测量方法:基波电流源与谐波电流源的输出分别经过各自的等安匝回路穿过CT线圈以实现一次电流的合成、通过匝数的变化可调节电流测量范围、通过改变谐波电流源的频率可实现谐波的成分变化,各等安匝回路中均串接标准分流器以便于溯源,其二次输出电压经串联叠加后形成标准量,与作为被测量的CT二次负荷电压通过差值法获得CT谐波特性。构建了等安匝合成电源并对CT试品进行了测试,测量结果验证了所提方法的有效性。

ABSTRACT：In order to solve the problems occurred in CT’s harmonic characteristics measurements such as the large fundamental currents, the controllable components and amplitudes of the harmonic currents and the difficulty of tracing to the sources, a measurement method of CT’s harmonic characteristics realized by equal ampere-turns synthetic power was proposed as below. The outputs of the fundamental current source and the harmonic current source respectively passed through the CT’s coils and theoretically join as one in terms of the magnetic field effect. The current measurement range could be adjusted by changing the number of the ampere turns and the components of the harmonic current could be changed by changing the frequency of the harmonic current source. For tracing the sources, standard shunts were serially connected in all the equal ampere-turns circuits, and the secondary output voltages of the shunts serially added as the standard voltage. The CT’s harmonic characteristics could be obtained by using the interpolation method between the standard voltage and measurements of the CT’s secondary load voltage. An equal ampere-turns synthetic power was constructed and CT samples were tested. Finally, the measurement results demonstrate the effectiveness of the proposed measurement method.