Coordination of intelligent controllers for shunt and series converters of UPFC

In order to utilize the existing transmission line to its full capacity Flexible AC Transmission system (FACTS) are used. The power flow control is effective if all the elements of the transmission line must be varied simultaneously or individually. To achieve this, the key appropriate FACTS device is Unified Power Flow controller (UPFC). The use of conventional controllers delays the decision making process to take suitable control action during dynamic conditions. In this paper a fuzzy logic based controller is used to generate supplementary damping signals and to control the shunt converter of IPFC. Two separate neuro-controllers are used for series converter control. Hence coordination between shunt and series converters of UPFC is achieved. The results in MATLAB environment will explain the performance of UPFC during step change of real and reactive powers.