Research on the control strategy of multi-terminal low frequency transmission system for island power supply scenes

In recent years, with the rapid development of the national economy, the national electricity consumption has increased significantly. Under the scenario of island power supply, the contradiction of insufficient transmission capacity is particularly prominent. Therefore, it is necessary to increase the transmission capacity of the existing lines or to build new transmission lines. As a new type of transmission technology, low-frequency transmission technology has the advantages of relatively increased transmission capacity, no circuit breaker technology bottleneck, and the energy release rate of low-frequency AC (LFAC) system is significantly lower than that of DC system. Therefore, LFAC transmission technology is a very competitive transmission technology in island power supply scenario. This paper analyzes the advantages and disadvantages of various transmission technologies, studies the control strategy of AC-AC converter and the coordinated control strategy of multi-terminal LFAC power grid. The master-slave control strategy of multi-terminal LFAC transmission system is proposed. The simulation model of four -terminal LFAC transmission system is established in PSCAD / EMTDC. Through the simulation analysis of the proposed control strategy, the feasibility and effectiveness of the control strategy are verified.