A Study of Medium Voltage Flexible Loop Closing Control Strategy Based on Sen Transformer

With the diversification of loads in the power system and the integration of large-scale distributed power sources, the distribution network architecture of “closed-loop design and open-loop operation” can no longer meet users' needs for reliable power supply and flexible operation of the distribution network. The on-load voltage regulation device, as a power flow controller, can achieve flexible interconnection in the distribution network and contribute to balancing power flow, exploiting distributed power sources, and improving power supply reliability. This paper proposes a flexible interconnection technology, based on a Sen transformer, that uses thyristors and multi-winding transformers to construct a hybrid transformer to achieve multi-level fast voltage regulation. And control strategies such as low impact loop closing operation and power flow transfer are studied to ensure that the loop closing device is cost-effective, provides uninterrupted load transfer, and regulates power flow distribution, thus meeting the demand for medium voltage flexible loop closing operation.