Development of New ZCT-sensor with Free Form and Size

This paper describes the development for ZCT sensor that enabled the flexible change of own size and shape. The proposed ZCT sensor is consist of the loop of plural pieces of the magnetic-induction units with the core and coil. The magnetic-induction unit has the rotational axes at the both end which enabled the easy change of ZCT window size and own shape by increasing or decreasing the number of units. Also, the internal residual current of ZCT sensor can be reduced by connecting the coils in parallel. The residual current (primary current level) of less than 50mA is achieved for zero phase sequence current at 600A primary load current.