UPFC潮流控制与优化的研究

FACTS对电力系统暂态的控制作用已被广泛认可，但对稳态方面的作用仍需要进一步的研究。文中基于功率注入法，建立了统一潮流控制器（UPFC）的稳态模型，分析了UPFC的潮流控制特性，同时通过三维立体图像形象地显示出UPFC的控制范围。基于该模型，UPFC的潮流控制研究可转化为一个优化问题的求解。通过求解最优潮流问题可得到UPFC所在支路的传输功率、系统发电费用和系统网损。IEEE-14和IEEE-30节点系统的优化结果表明：UPFC对系统局部范围内的潮流有相当大的调节作用，但对于系统范围内的经济性目标却作用有限。这说明UPFC稳态控制能力依赖于系统的运行目标，因此UPFC在稳态下的最佳控制策略应该是与相应运行方式相结合的区域目标下的优化控制。该结论对UPFC的选址也有一定的参考价值。

A STUDY OF POWER FLOW CONTROL AND OPTIMIZATION BY UPFC

The control action of FACTS on power system transients has been extensively recognized.But its function on system steady- state operation should be further studied. In this paper,the power controlling characteristics of the U PFC power injection m odel is firstly analyzed with the aid of a three- dimensional diagram thus the scope of the U PFC on power flow control can be clearly displayed. With this model,the power flow control problem can be transformed into an optimization problem.Then the optim al power flow is undertaken and the power transmitted via interconnecting lines can be obtained. The com putation results of the two IEEE sample system s reveal that U PFC has quite powerful capability of controlling the local area power flow,but has only limited capability of reaching the objective of optimal operation of the whole system.This demonstrates the dependence of the steady- state controllability of UPFC on the operational objective of the system. The computation results also show that the optimal control strategy of UPFC under steady state should be the optimal control of the local area power flow incorporating with the corresponding operating conditions.This conclusion can also be referred during U PFC placem ent. This project is supported by National Natural Science Foundation of China for National Outstanding Young Investigators No.5 982 5 10 4 and National Natural Science Foundation of China for Oversea Young Scientists No.5 992 870 5 .