传统电流互感器一般采用闭磁路铁心设计，但受铁心材料存在磁饱和的限制，其在一次电流回路发生短路故障时，出现的直流电流分量会严重影响电流互感器的性能，导致其测量电流值的误差可能非常大。开口式电流互感器通过在磁路中引入空气隙，大大增加了磁路阻抗，可有效避免铁心饱和对电流互感器性能的影响。从开口式电流互感器的基本磁路和电路时域方程出发，建立了考虑二次侧负载效应时表征开口式电流互感器工作性能的解析模型。讨论了开口式电流互感器的不同参数对其工作性能的影响。所建立的解析模型，对实现测量用电流互感器与保护用电流互感器的兼容，以及提高用于电能表在线检测的钳形电流互感器测量准确度，均具有理论指导价值。

The current transformer conventionally employs a closed magnetic circuit design. But limited to the satura-tion of the magnetic core,when a short-circuit fault occurs in the primary coil,the DC current component will seri-ously affect the performance of the current transformer,leading to non neglectful errors for sensing the primary cur-rent. The air-gap-core current transformer increases the magnetic reluctance through the introduction of an air gap in the magnetic circuit,which can effectively reduce the core saturation with DC excitation. Based on fundamental e-quations of the magnetic and electrical circuits,an analytical model for the air-gap-core current transformer is pres-ented with considering the loading effect of the secondary coil. Influences of different parameters on the air-gap-core current transformer are discussed. The established model supplies basic theoretical guidance towards compatibility of an air-gap-core current transformer for realizing both measurem

运行在电力系统中的互感器数量众多，长期处于工作状态，其工作可靠性对整个电力系统的安全运行有着重要的意义。介绍了互感器的预防性试验。包括电压互感器绝缘试验、电流互感器绝缘试验及互感器特性试验。

Numerous mutual inductors, which are running in electrical power system, are subject to very long working hours, their operational reliability possesses important significance for the safe operation of the whole safety of the power system. This paper introduces the preventive tests of mutual inductors, including the insulation test of voltage mutual inductor, the insulation test of current mutual inductor and the performance test of mutual inductor.

电子式互感器是智能电网建设的关键设备之一，其性能直接影响到数字化变电站的安全和经济效益，也是电能计量准确的必要条件。电子式互感器的输出与传统互感器不同，分为数字输出和模拟输出两种，因此传统的互感器校准方法已经不适用于校准新型的电子式互感器。文章以模拟量输出的互感器为例，创新性地提出了采用精密分流器和示波器测量比值差和相位差，并对校准数据进行了验证，测量结果满意。

Electronic instrument transformer is one of the key equipment for smart grid construction. Its performance di-rectly influences the safety and economic benefits of digital substations,and it is also the necessary condition of accurate power measurement. Different from conventional electromagnetic transformers,the output signal of the electronic instru-ment transformer can be classified into two categories,namely digital output and analogue output. Therefore,conven-tional calibration methods are not suitable for electronic instrument transformer testing. Taken the electronic instrument transformer with analogue output as an example,this paper puts forward employing precise shunt and oscilloscope to measure ratio error and phase displacement. The calibration data are verified,and the results are satisfactory.

综述了电子式互感器基本原理、分类和优点,与传统型互感器进行了性能比较,对电子式互感器的应用和前景做了分析.

Overview of the fundamentals of electronic transformers, classifications and benefits, performance comparison with the classic transformers. Application and prospects of electronic instrument transformers are analyzed.

由于传统的互感器误差测量装置,其智能化程度比较低且测量精度不够高,故提出了一种基于DSP的电磁式互感器误差测量新技术。设计的互感器误差测量仪可在现场或实验室环境下,通过比较从标准互感器与待测互感器所采集的信号,完成对互感器误差的测量。设计的程控放大电路对原始信号进行幅值的调节,低通滤波器使输入AD转换器的信号为有效的基波信号,并兼顾其整体的抗干扰性能。采用DSP作为核心控制器,其反序间接寻址等特性能有效地对数据进行FFT运算,得出待测互感器的比差和相角误差。采用这种互感器误差测量仪可以提高效率,实现测量过程的自动化。

A new DSP-based error measurement for electromagnetic is proposed, aiming at the low lntelligent degree and measurement accuracy in traditional electromagnetic transformer calibrator. The error measurement for electromagnetic instrument transformer can be achieved by comparing the signals collected from the standard transformer (ST) and the detected transformer (DT) in the field or laboratory environment. The original signal amplitude will be regulated by the designed programmable amplifying circuit, and the low-pass filter will make the the signal passing AD converter be an effective fundamental harmonic signal. The anti-interference performance is also being concerned. DSP is taken used as the core Microcontroller. The FFT algorithm is applied to realize frequency spectrum computation. By comparing the data of DT with the data of ST, the ratio error and phase error are obtained. The results show that the measuring device can enhance the test efficiency and make the process automatic.