Subsynchronous Oscillation Characteristic Study of Wind-Thermal Power Bundling And EHV AC-DC Hybrid Transmission System

There is the risk of subsynchronous oscillations when wind-thermal-bundled power supply delivered through AC transmission line with series capacitance compensation and high voltage DC system. However, the current researches are all aimed at the subsynchronous oscillation of wind-thermal-bundled power supply or AC-DC hybrid transmission, without considering the subsynchronous oscillation of wind farms, thermal power plants, AC transmission system with series capacitance compensation and DC transmission system at the same time. The linearized model of wind-thermal power supply and extreme high voltage (EHV) AC-DC hybrid transmission system is built firstly in this paper and then subsynchronous oscillation mode of system is analyzed by factors related with characteristic values. This study uses characteristic values sensitivity make sure the main influencing factors of subsynchronous oscillation and then analyze the influence of AC-DC transmission power distribution, thermal power and wind power output allocation, wind power control parameters and DC transmission control parameters on subsynchronous oscillation. The correctness of theoretical analysis is verified by the simulation results.