Analysis of Subsynchronous Torsional Vibration of Wind-Thermal Bundling Delivery System via LCC-HVDC

Recently, Wind-thermal bundled transmission via LCC-HVDC has become the main way of wind energy development and utilization in my country at present and in the future. The complex interaction between wind turbines, thermal power units, and LCC-HVDC needs to be further studied. In this paper, aiming at the direct-drive wind turbine group, thermal power unit and HVDC, the linearization model of the system is established, and the interactive coupling relationship between the connected equipment and the electrical damping of the thermal power unit is analyzed, and the mechanism of torsional vibration of thermal power unit shafting caused by wind-thermal bundling via LCC-HVDC is studied. mechanism. Based on the complex torque coefficient method, the influence of factors such as wind speed, control parameters, HVDC transmission power and control parameters on the electrical damping coefficient of thermal power units is studied. Finally, a time-domain simulation model is built in PSCAD/EMTDC, and the effectiveness of the electrical damping coefficient analysis results is verified through time-domain simulation and time-frequency analysis.