Research on Adaptive Differential Protection of Voltage-regulating Transformer Based on Gear Information Tracking

In the process of on-load voltage regulation of the voltage-regulating transformer, the differential protection device cannot adjust the balance coefficient according to the ratio of the real-time rated current, resulting in a great error in the differential current calculated by using a fixed ratio of the rated current on both sides of the transformer. In practical engineering, there are great potential safety hazards without differential protection, and the application of insensitive differential protection reduces the sensitivity of the differential protection and also increases the complexity of the voltage regulation operation of voltage-regulating transformer. Accordingly, this paper proposes an adaptive differential protection scheme based on gear information tracking. Firstly, the real-time tap position information of voltage-regulating transformer is obtained through the input of transformer gear information based on BCD code, and then two differential protection implementation schemes including adaptive balance coefficient adjustment and fast value area switching are proposed, which are used to improve the differential protection configuration strategy of on-site voltage-regulation transformer and solve the problem that the application of the differential protection principle is difficult due to the wide range of voltage of the voltage-regulating transformer. At the same time, in view of the abnormalities that may be caused by the collection of on-load voltage regulation gear information, a variety of verification methods for gear information abnormalities are proposed.