Enhancement In Transient Stability Of Electrical Power System By Using UPFC And Other FACTS Devices

Now a day’s power system growing in an exponential way because of extensive automated requirement of domestic as well as industrial requirements.This consistently increasing needs of power network has result into rotor angle oscillations and voltage instability.It is precisely due to the inability to generate the required reactive power and real power control that propounds the cause of voltage collapse and rotor oscillations.Electromechanical oscillations at low frequency are inevitable characteristics of power systems which ultimately render the stability of power system and decrease the loading capacity of a transmission line.In conjunction with that,because of political and environmental issues,such as the construction and locations of new power plants as well as the impediments of erecting new transmission facilities,it is necessary to make maximum use of existing facilities.The implementation of flexible alternating current transmission system(FACTS)can be a significant option to resolve these problems and damping of power system oscillations is compensated by PSS and FACTS devices.Utmost consideration is given to flexible alternating current transmission system(FACTS)device,which is directed from latest power electronic components.Among the popular FACTS devices,a unified power flow controller(UPFC)has demonstrated an optimal performance.In this thesis,the design stages of fuzzy control scheme for dynamic Unified Power Flow Controller(UPFC)with suitable methods including Larsen implication and Centre of gravity for the UPFC application has been proposed and the corresponding parameters have been chosen.This proposed strategy provide fast response during dynamic operations,significantly reduces the size of oscillations with less settling time,and it is robust to system parameters changes.A proposed multi-band power system stabilizer controller with better damping characteristics is designed in coordination with a unified power flow controller(UPFC)and the control scheme of the UPFC are established based on the proposed MBPSS-controller.The proposed technique addresses the design problem and controls the multi-control strategies of the UPFC under a dynamic load condition.The third part of this thesis includes the study of a suitable approach to damp the power oscillation and to increase the transient stability of the system by using SSSC with and without POD.In addition the parallel operation of SSSC with POD is analyzed to increase the power transfer and hence rising the load capacity.The last part of this thesis includes,a simulation model of a 132/11 kV substation main network with 54 buses of Bahawalpur region in Pakistan on ETAP software is established and Load Flow study is done in order to find the amount of drop in voltage and power.Marginal as well as critical buses are analyzed.In addition the placement of SVC is determined.