Investigation of UPFC–EDS effects for static and dynamic voltage stability in power systems

Nowadays, Flexible Alternating Current Transmission System (FACTS) devices, which are based on power electronics, are widely used in the control of transmission lines and bus. FACTS devices are preferred in different analysis approaches of power systems. Unified Power Flow Control (UPFC) is the most powerful controlling capability among FACTS devices. The UPFC controls bus voltages based on reactive power, while controlling the transmission line according to impedance and current. In this thesis, static and dynamic voltage stability analysis of UPFC has been carried out in the International Electrical-Electronics Engineering (IEEE) 14 bus power system. Power Systems Analysis Toolbox (PSAT) was used for the analysis of IEEE 14 bus power system. In order to improve the static and dynamic voltage stability operating limits and to keep the system in a stable area, A fuel cell from the Energy Storage System (EDS) components was used together with UPFC. In the steady state study for static voltage stability, while UPFC-EDS is connected to different transmission line and different load bus are examined to loading events of the system, the voltage-maximum load parameter relations for the case of outline occurring in the transmission line for dynamic voltage stability analysis are examined with UPFC-ESS. Besides, bus voltage profiles were analyzed with UPFC-ESS. When UPFC and EDS are used together, it is seen that the loading parameter value of the system increases and bus voltage profiles are improved.