Amit Kumar Yadav, Rahul Arora, Sachin Tiwari, Shadma Khan, Abhay Chaturvedi   Oriental Institute Of Science and Technology, Bhopal, India  Nri Institute of Information Science and Technology, Bhopal, India
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Abstract – This paper addresses the comparative load flow analysis with and without Unified Power Flow Controller (UPFC) for six buses, three phase transmission line under L-L-L-G fault in simulation model. Unified Power Flow Controller (UPFC) is a typical Flexible AC Transmission System (FACTS) device playing a vital role as a stability aid for large transient disturbances in an interconnected power system. The main objective of this paper is to improve transient stability of the six bus system. Here active and reactive power on load bus of the system considered has been determined under L-L-L-G fault conditions. UPFC has been connected to the system and its effects on power flow and voltage profile of test system has been determined with various line data and bus data for six buses, three lines power system and simulation model by using simulation toolbox has been developed. In this work a versatile model is presented for UPFC inherent order to improve the transient stability and damp oscillation.
Index Terms – Unified Power Flow Controller (UPFC), Control, simulation, transients, Matlab, Three phases to ground fault (L-L-L-G)
The Unified Power Flow Controller (UPFC) concept was proposed by Gyugi in 1991. The UPFC was devised for the real-time control and dynamic compensation of AC transmission system, providing multifunctional flexibility required to solve many of the problems facing the power delivery industry within the framework of traditional power transmission concepts.UPFC is able to control, simultaneously or selectively, all the parameters affecting power flow in the transmission line (i.e. voltage impedance and phase angle). Unified Power Flow Controller (UPFC) is a typical Flexible AC Transmission System (FACTS) device playing a vital role as a stability aid for large transient disturbances in an interconnected power system, UPFC for improving the performance of the power system. Two objective functions are simultaneously considered as the indexes of the system performance, maximization of system load ability in system stability margins (voltage stability index and line stability factor) and minimization of active power losses in transmission line by considering installation cost of UPFC controller [1-2]. The transient experiments proved that UPFC can improve the stability of power grid. The MATLAB simulation results are taken to prove the capability of UPFC on power flow control and the effectiveness of controllers on the performance of UPFC in the different operating modes [3-4]. A unified power controller offers substantial advantages for static and dynamic operation of power system. But it also brings with its major challenges in power electronic and power system design [5-6]. A transient stability and power flow model of a...