Preliminary research on the power flow control method of the distribution network with normally closed-loop operation based on the SSSC

With the development of digital technology, the temporary interruption problem in some economy developed areas has been pay great attention. The normally closed loop operation mode of distribution network with seamless fault self healing technology, is an effective solution to avoid the temporary interruption and improve the power supply reliability. This paper analyzes the normally closed-loop operation types and the power flow distribution characteristics. In order to control the circulating power and balance the output power of both-side feeders, it presents an optimal power flow control method based on the Static Synchronous Series Compensator (SSSC). Taking the minimal loss of the network into account, the controlling strategy of series compensating voltage produced by SSSC is derived in detail, and the constraint situation of the normally closed loop operation is proposed. The optimal control method fits to both three-phase balanced system and unbalanced system. This method can effectively control the closed-loop power flow and optimize the load distribution. The simulation result proves its feasibility.