| With the development of the digital substation and the advancement of the smart grid,the electronic current transformer is used widely. It is mainly applied in power system,such as measuring, protection, monitoring and so on. Its accuracy and stability will affectthe safe and stable operation of power system. Therefore, it is very important to calibratethe electronic current transformer on-line. In order to calibrate the electronic currenttransformer, the standard current transformer is needed. The standard current transformermust have a high precision and be able to be installed on-line. In addition, for somespecific measurement applications, it also requires the current transformer, whichpossesses a high precision or a wide range or an easy installed structure, as the conversiondevice. Thus, the current transformer with a high precision and an open-close structurewill have a broad application prospect and an important research value.This paper studies and designs the current transformer with a high precision and anopen-close structure. Firstly, this paper introduces the commonly used magnetic materialsand its related performances, analyzes the influences of the air gap on the magneticproperties, and expounds the principles of selecting the iron core. Secondly, this paperanalyzes the transfer function model of the single stage current transformer with aopen-close structure, summarizes the factors for influencing the precision, studies themethods for decreasing the error, puts forward three effective compensation methods, andgives the principle of their application. Finally, this paper designs and tests the currenttransformer with a high precision and an open-close structure, analyzes the test data, andverifies the correctness of the design methods of the current transformer.In this paper, the error compensation methods put forward have good theoreticalguidance on the design of the high-precision current transformer and strong practicability.The current transformer designed not only can be installed on-line due to the open-closestructure, but also can calibrate the current transformer with a0.2accuracy class. |
