Large-Disturbance Stability Analysis of Flexible Interconnected System of Distribution Areas Considering Load-Balancing

With the proposal of the “dual-carbon” target and the rapid development of distributed generation technology, distribution areas (DAs) are faced with the problems of difficult to expand capacity, difficult to consume distributed generation, unable to effectively use the remaining capacity of each DA, etc. The flexible interconnection system (FIS) has gradually become a solution to improve the power supply level of DAs. To fully utilize the advantages of the flexible power flow control of FIS, a $v_{\mathrm {{dc}}}-P_{\mathrm {{grid}}}$ droop control strategy is proposed, which takes into account load balancing. This strategy balances the AC source output of each DA during normal operation. Subsequently, a simplified circuit model of the system is developed, and the stability of the system is analyzed under large disturbances when a constant power load is connected to the DC bus, using the mixed potential function theory. The stability criteria of the system is obtained, and verified by the real-time hardware-in-loop (HIL) tests.