Study On Transient Stability For Wind-thermal-bundled Power Transmitted By AC/DC System

Wind power bundled AC and DC delivery of the transmission mode to effectively solve the problem of adverse distribution of energy reserves and load demand in China is the future of 10 million kilowatts of wind power base to send the main way of electricity.However,most of the wind-fire bundled sending-end systems are located in the weak areas such as the northwestern grid.A large number of wind power,thermal power,exchange and direct current coupling make the system’s dynamic characteristics extremely complex and urgently need to be studied.In this paper,in-depth study on the transient stability of wind-bark AC-DC delivery system,focusing on the influencing factors,the impact mechanism,measures to improve and so on.Firstly,based on the PSD-BPA power system simulation software,a model of AC-DC typical outgoing system was established,and a wind power output modeling method based on the principle of equivalent polymerization was proposed.Based on typical system simulation,the reactive power control mode and the reserve capacity of the wind turbine are introduced to the transient stability of the system.Based on this,a quantitative description of the transient stability is proposed and the transient stability of the system under different boundary conditions is analyzed the key factors influencing the transient stability of the system due to wind-fire coupling are analyzed.Based on the extended equal area rules and the unbalance dynamics theory,the transient acceleration energy of the windward-fire bundled delivery system is deduced as the system inertia changes Function expressions,explain the different transient stability of the system under different boundary conditions.Then according to a typical operation mode of actual system of AC-DC delivery in north Shaanxi in 2006,the transient stability of the AC-limited system and DC-blocking system under different proportion of wind power is simulated and analyzed.The differences explain the existence of the tangential weakened cross coupling effect in the AC-DC outgoing system in northern Shaanxi.Finally,the dynamic coupling effect between wind power and power grid after system instability is simulated and analyzed in the actual system.Based on this,the cutting machine control method of wind-binding system is studied,and the factors such as the cutting machine volume and cutting machine location are analyzed.The influence of different cutting machine control methods for wind power and thermal power on the transient stability of AC-DC AC power transmission system in northern Shaanxi Province.Based on the economy and stability of the actual system operation,a control strategy of wind-fire combined cut-off control is proposed.The actual system instability after the emergency control has a guiding role.