Locating and sizing of partition flexible interconnection converter station in large urban power grids

Partition flexible interconnection (PFI) is a new way to change the partitioned operation situation of urban power grids so as to promote their security, stability and flexibility. Locating and sizing of the PFI converter station (PFICS) is a key question. In this study, the concept of PFI and the operation mode of the converters are presented at first. An integral locating and sizing method of PFICS is proposed, which is divided into three stages – preliminary selection, location optimisation and capacity design. The preliminary selection can avoid many unnecessary simulations. In the second stage, the optimal location is determined by comprehensively comparing five indices (static security, transient voltage stability, power supply reliability, load balancing and total supply capacity) based on the analytic hierarchy process. In capacity design stage, the maximum VAR capacity curve is obtained via deduction, then the capacity of the PFICS is determined according to power demands of the two interconnected partitions. Finally, the proposed method is verified by the real PFI project in power grid of Beijing (China).