Multi-time Scale Vsc-mtdc Coordinated Control For Renewable Energy Integration

Nowadays,to achieve China peak carbon dioxide emission and carbon neutrality objectives,improving the renewable energy consumption and energy storage application have been the national major strategy.As the large-scale and high-proportion renewable energy has become an important development trend of the power system,VSC-HVDC technology overcomes the long distance power transmission difficulty,environmental problem and economic problem.Moreover,it solves the technical problems including power flow control stability,renewable energy integration,power quality and asynchronous interconnection.To achieve diverse AC system demands,it is inevitable to build the VSC-MTDC system.With the diverse VSC-MTDC system characteristics development,a flexible and controllable coordinating control potential is provided for multiple AC applications with the DC grid.However,due to the mutual influence of various demands such as maximum renewable energy consumption,DC grid abnormal operation,peak load regulation,the characteristics of various devices under different time scales are coupled with each other.Thus,how to coordinate the demands and characteristics of each terminal to achieve DC grid coordinating control in different time scales has become a problem.The VSC-MTDC system multi-time scale coordinating control for large-scale renewable energy integration are proposed.The main researches are as follows:1)The VSC-MTDC system and station control mechanisms are analyzed.Focusing on the interconnected AC system characteristic demands,the system coordinating control strategies and station control strategies for different AC applications are explored.Based on the multitime scale coordinating control demands,the VSC-MTDC coupled control characteristics for multiple AC applications are proposed.2)The multi-time scale VSC-MTDC coordinating control strategy is proposed for multiple AC applications.The long time scale operation strategy is discussed for different AC applications demands,and the power scheduling and unit configuration strategies are proposed.The scheduling optimization strategy and the appropriate system control strategy are discussed for different operation conditions in the medium time scale.Finally,the coordinating control strategy is proposed for short time scale demands.3)Based on the multi-time scale VSC-MTDC coordinating control strategy,the specific coordinating control strategy is proposed for the large-scale renewable energy integration scenario in the Zhangbei VSC-MTDC system.The VSC-MTDC system,pumped storage power stations and renewable energy fields characteristics are analyzed for the multi-time scale coordinating control scheme.Then the coordinating control strategy is verified in the Zhangbei VSC-MTDC simulation system.4)Based on the multi-time scale VSC-MTDC coordinating control strategy,the black start coordinating control strategy is proposed for the Zhangbei VSC-MTDC system.According to different time scale black start demands,the system configuration is planned in the long time scale.The medium and short time scale coordinating control strategy is proposed to solve the medium time scale startup timing,short time scale startup strategy and the startup overcurrent problems.Finally,the proposed black start strategy effectiveness is verified based on the Zhangbei VSC-MTDC simulation system.