Stability enhancement of Western grid of Bangladesh using Unified Power Flow Controller

Flexible AC Transmission System (FACTS) plays a key role to enhance the stability of power system. Stability is of vital importance as it sets the limit of the power system before it reaches to its thermal rating. Voltage, transmission angle and line reactance are the three major parameters to control the power system. Unified Power Flow Controller (UPFC) is the second generation FACTS device which can control the parameters of power system, thus it has the capability to enhance the stability of the system. Bangladesh Power System (BPS) has two Interconnectors (ICs). First IC has 315 MVA thermal capacity and second IC has 630 MVA capacity. Due to stability limitations they can’t be used up to their thermal limit. So a UPFC is adopted in first IC to increase the stability limit. A suitable tuned controller is used with UPFC to increase the dynamic stability limit. Modal analysis technique is used to analyze the system stability. NEPLAN software is used to carry out all the simulations.