Power system stability enhancment using UPFC damping controller

The rising of demand of power and difficulties of constructing a newly transmission network causes the power system to be complex and stressed. Due to the stress in the power system there is a chance of losing the stability following to the fault. When the fault occurs in the power system the whole system goes to severe transients. By using PSS and AVR we can easily stabilize the system. FACTS devices (i.e. TCSC, SVC, STATCOM, and UPFC) are extremely important to suppressing the power system oscillations for faults and it also increasing the damping of the system. The power electronic device named as UPFC which efficiently control the active and reactive power. This thesis reflects a novel control technique which is based on Fuzzy Logic technique to provide external controlling signal to UPFC which is mounted in a single-machine infinite bus system to suppress low frequency oscillations and also it describes the model of a UPFC with multi-machine system which is externally controlled by the signal which is generated by the newly proposed power flow controller to increase the stability of the system with occurrence of fault in which it connected. The proposed controller consists of Power oscillation damping controller and Proportional Integral Differential controller (POD & PID). The effectiveness of controller for suppressing oscillation due to change in mechanical input and excitation is examined by investigating their change in rotor angle and speed occurred in the SMIB system. FACTS devices are used the existing transmission system very efficiently with the specified stability margin