Coordination strategy and its realization of UPFC control protection system and power grid protection for improving fault ride-through capability

In this paper, the structure and the fast fault isolation technique of UPFC is introduced firstly, and then a coordination strategy of UPFC control protection system and power grid protection is put forward for improving fault ride-through capability. Based on comprehensively analyzing UPFC control protection system operation, AC protection operation, power gird status and switch position, the most appropriate operation mode of UPFC such as shutdown, switching mode or restarting to the original mode is determined, and that is executed coordinating with AC protection operating by the strategy. As the part of the strategy, the discrimination principle and implementation method of the strategy are represented in detail. The strategy is verified in system commissioning and operation of Western Nanjing 220kV power grid UPFC project and closing-loop test for control protection system of Southern Suzhou 500kV power grid UPFC project. The result shows that the strategy can further improve UPFC fault ride through capability.