The Research Of FACTS' Devices Impact On The Long-term Reliability Of Power System

Studying on how FACTS allocation affects the long-term reliability of power system, therefor choosing the optimal sitting for FACTS devices for the most flexibility in control, minimum investments and maximum benefits is of great importance for engineering practice. The thesis proposes a new method for FACTS'optimal location by using of Lagrangian multipliers of inequality constraints to find the most sensitive position, where little changes on the power flow limits or voltages'limits could change the value of the objective function in our expected direction the most. Based on the algorithm, the effects of FACTS on the reliability of the power system are studied under both the short-term frame and long-term frame. Test results show that under the short-term frame, the application of FACTS can significantly reduce the EENS and EDNS, while under the long-term frame, FACTS can reduce the frequency of outages to some extent, but due to the capacity limit of FACTS, there is no big improvement on the alleveation on the risk of large blackouts. Moreover, differences on line upgrade capacity, FACTS'capacity and the object of system optimal operation affect the long-term development of the power system, then affect the reliability of the system in different ways.