Study On Reliability Of Redundant Protection Configuration For Large-sized Generator-transformer Block

Redundant protection system is adopted to generator-transformer unit, according to the relative documentations from the State Grid Corporation of China. However, after using redundant protection system, the performance of reliability is unimproved compared to the selectivity, speedity and sensitivity, from the requirements of the four behaviors and the effect of generator-transformer unit. False tripping often occurs to make it as the troublesome problem of the system. On the other hand, each company applys its own method to avoid false tripping, because of the lack of a common principle.Based on the requirement of the documentation, this paper gives the main elements of affecting the relay correct operation for the generator transformer unit, and makes a conclusion for both the protection equipment and formative requirements, with a brief description for the general microcomputer based primary protection principles.Beside this, it is further bring about the concerned microcomputer based duplicate protection equipment issue, and gives a analysis to the option of relay internal adapted principles and external PT, CT choice and installation.As the development of the power system and the increment of the generator capacity, it is very ugent to improve the performance of reliability. Based on the relative documentations, the hardware, software and power source supply of the protective device is studied carefully. At last, the paper brings forward some advice combined with the practice to improve the performance of reliability.