含风电电力系统电压稳定问题的分岔

Bifurcation of Steady State Voltage Stability with Wind Power System

为了揭示含风电电力系统的分岔现象及电压失稳的机理,对3机9节点的电力系统加入风电场(基于恒速恒频机组构成)并网等值模型进行仿真研究,以MATLAB软件为计算工具,用延拓法追踪系统平衡解流形;用分岔理论中的直接法计算鞍结分岔点。引入电容补偿的动态数学模型,以风电场注入有功功率和电容补偿为控制参数,对系统进行单参数分岔分析和双参数制约性分岔分析。在有效参数变化范围内对系统平衡解流形的追踪表明:在高注入功率的情况下发生鞍结分岔;对风力发电机组进行有效的电容补偿,能够抑制鞍结分岔,系统各节点的电压得到有效抬升;在解流形的下半解支搜索到动分岔点。

Combined with wind farm model ,a simple 3-machine 9bus power system is simulated to reveal the bifurcation phenomena and mechanism of voltage instability. The simulation was carried out under Matlab software environment, and continuation method was adopted in tracing equilibrium solution manifolds of the system;and the saddle-node bifurcation point was calculated by direct method. The dynamic model of electric capacity was introduced into the mathematic model of the system. The injecting active power of wind rarm and capacity compensation were treated to be control parameters in bifurcation analysis. In the availably parameters＇scope,the equilibrium solution manifolds indicates that saddle-node bifucation are encouter while heavy active power of wind farm in jecting;when effective capacitance compensation is applied in the wind trubine generator, saddle-node bifurcation is avoided and voltage of each node in the system is efficiently pulled up. The simulation also shows that Hopf bifurcations are found at the part of unstable equilibrium solution manifolds.