空心线圈作为保护用电流互感器的理论分析和试验

开发新型电子式互感器是电力系统自动化和数字化的一个发展方向，文中论述了空心线圈用做电流互感器的工作原理及与传统互感器的不同之处，根据保护的要求，重点分析了频响工作特性，并针对具体对象研制了样机。样机试验结果为：对保护，在2 kHz频宽、20倍额定电流范围内，误差小于1%；对测量，可达0.2级。理论分析和试验结果证明空心线圈电流互感器以其线性好、频带宽、无饱和、体积小等优点能完全满足电力系统保护和测量的需要，而且特别适用于微机化保护装置和电子式测量仪器。

A STUDY ON THE AIR-CORE COIL CURRENT TRANSFORMER FOR PROTECTIVE RELAY

The new type of electronic transformers will play more and more important roles in power system automation and digitalization. The paper presents the principle of the air-core coil current transformer and points out the differences between the electronic transformers and the traditional ones. Amplitude-frequency characteristic has been analyzed according to the requirements of protective relay, thus a sample prototype is further developed. Moreover, the result of the tests shows that, for protective relays, the error is less than 1% under the scope of the frequency 2 kHz and twenty times rated current as much, and measurement accuracy can reach class 0.2. Theoretical analyses and test results verify that the air-coil current transformer can completely satisfy the requirements of power system for its good linearity, broad band, non-saturation and economical bulk and especially be used for computer protective relays and electronic measurement equipments.