改善连锁脱网的风电场群电压无功紧急控制策略

针对大规模风电场动态电压问题可能导致的连锁脱网事故,首先分析并仿真验证了风电场连锁脱网的演化机理及时空特性;在对风电场内的无功源及双馈风电机组的调节特性进行分析的基础上,提出了协调静止无功补偿器(SVC)和双馈感应发电机(DFIG)机组的电压无功紧急控制策略,控制的原理是利用DFIG的有功、无功解耦控制,在故障时由SVC和风电机组共同输出容性无功功率,提高故障中的风电机组端电压,同时对DFIG的有功功率进行限幅;故障清除后,风电机组依据电压情况迅速输出一定的感性无功功率,以抵消SVC的滞后效应。仿真结果表明,所提紧急控制策略能够很好地抑制大规模风电场的连锁脱网事故。

Voltage and Reactive Power Emergency Control Strategy of Wind Farm Cluster Against Cascading Trip-off

For possible cascading trip-off events caused by dynamic voltage problem of large-scale wind farms, the evolution mechanism and special spatiotemporal characteristic of cascading trip-off of wind farms is analyzed first and verified by simulation. Then the reactive power sources in wind farms involving doubly-fed induction generator (DFIG) and their regulation characteristics are analyzed. The voltage and reactive power emergency control strategy is put forward using static var compensator (SVC) and DFIG. The control principle proposed consists in using DFIG and SVC to jointly output capacitive reactive power during the fault based on the decoupled control of DFIG, at the same time to limit active power output of DFIG, so as to increase the voltage of DFIG. Fault cleared, DFIG provides some reactive power according to its terminal voltage to offset the lagging effect of SVC. Simulation results show that the emergency control strategy proposed is able to successfully suppress large-scale cascading trip-off of wind farm cluster. This work is supported by the Major Program of National Natural Science Foundation of China (No. 51190103) and State Grid Corporation of China (No. SGNX0000FZJS1400729).