Compensation Strategy for Multiple Series Centralized Voltage Sag in Medium Voltage Distribution Network

In order to solve the major production accidents caused by voltage sag in power supply park, such as equipment shutdown and production line shutdown, this paper proposes a new DVR topology to compensate voltage sag. In this strategy, the storage battery is centralized for energy management, and the stored energy is output through the combination of multiple converters and multi-winding transformers. Based on this topological mathematical model, this paper presents a hybrid control method of grid voltage feedforward and load voltage feedback, which can compensate the large capacity, long, deep and asymmetric voltage sags in the medium voltage distribution network. In addition, in order to solve the problem of DC bias caused by the circulating current between multiple windings on the secondary side of transformer, a circulating current suppression algorithm is proposed. The effectiveness of the proposed strategy is verified by matlab/simulink simulation analysis and experiments.