PERFORMANCE ANALYSIS OFAIR-CORE CURRENT TRANSFORMER

The principle, structure and output signal of an air-core coil current transformer are different with that of a traditional current transformer of the inductive type. The performance of an air-core coil current transformer could be affected by temperature and disturbance magnetic field. In this paper, the influences of temperature and disturbance magnetic field to an air-core coil current transformer are analyzed in detail. Some measures to improve the performance of an air- core coil current transformer are proposed. According to the improving measures, an air-core coil current transformer that can be used in 220kV GIS has been developed and tested. Testing results showed that the influences of disturbance magnetic field and temperature to the improved transformer are very small, the frequency characteristic and transient behavior of the transformer are perfect, and the accuracy of the transformer is better than class 0.2.