Research of short circuit Level Improvement of Transformation Substation Equipment

During the 15th Five-year Plan period, with the access of DC and its supporting power supply, the overall short circuit current of northwest power grid continues to rise, and short circuit current of more and more substations will be more than 63 kA. When there are no measures to limit the short circuit current by adjusting the grid structure, installing the series reactor or the fault current limiter, it is particularly urgent to develop a higher block capacity circuit breaker and other equipment in the distribution device to meet the needs of the future development of the power grid. According to the system forecast, the recommended short circuit current level is increased from 63 kA to 80 kA. Through the investigation of the mainstream substation equipment manufacturers at home and abroad, theoretically there is no insurmountable technical bottleneck problem of increasing the short circuit current level from 63 kA to 80 kA. According to the research results of the equipment manufacturer and the transformation design experience, this paper proposes the design requirements of increasing the short circuit level from 63 kA to 80 kA.