Study On Main Protection And Application For UHV Transformer

UHV transformer is one of the most important equipments in the UHV system. The operation state of UHV transformer plays a key role for the security and stability of the entire power system,particularly UHV system.It is necessary and significant to study the UHV protection configuration,inrush recognition and setting calculation.The structure of UHV transformer is different from the traditional transformer.The overall configuration scheme is summarized.Phase differential protection and limit zone differential protection for low voltage side are configured for UHV transformer.It is concluded that voltage regulator and compensation transformer differential protection must be configured separately. Inrush characteristic for UHV transformer is analyzed.Two methods for solving inrush recognition are provided.The first is eliminating the remanence of the transformer so as to improve the 2^nd harmonic content.And then a new comprehensive inrush recognition method is provided,which is proved valid and feasible by the dynamic simulation and the UHV debugging waves replaying.In order to adapt to the structure and the operating characteristics of the regulator compensation transformer,the protection setting calculation scheme is provided.