Research on load transfer strategy optimisation with considering the operation of distributed generations and secondary dispatch

Abstract

In this study, a three-stage optimisation method for distribution system load transfer scheme with consideration of the participation of distributed generations (DGs) is proposed. The algorithm aims to recover loads from the large-scale power outage caused by substation-complete-shutdown accidents (SCSAs), thus improving the power supply reliability. First, the principle of the SCSA load transfer strategy considering DGs and the secondary dispatch is introduced. The capacities of DGs were used to provide the additional power supply in grid-connected or island operations. Meanwhile, to relieve the stress of the backup substation for further load transfer, a secondary dispatch strategy is proposed to dispatch loads among the direct-connected and secondary-connected substations. Afterwards, a three-stage optimisation model is built to obtain the optimal load transfer scheme. The first-stage optimisation determines the island partitions in the unrecovered areas. The second-stage optimisation comprises a tie-line transfer model considering the load importance and the recovery time. The third-stage optimisation intends to determine the optimal secondary dispatch to achieve a better overall recovery rate. Case study results prove that the proposed three-stage optimisation method can improve the overall load recovery rate while ensuring the reliability of important loads and the operation safety of the system.