Improvement of Power Flow Capability By Using An Alternative Power Flow Controller

An improved version of power flow-controller (PFC) which is based on multi-winding transformer (MWT) is presented in this paper. The objective of this article is to control the power flow in a power-line to alleviate overload in a heavily loaded system and increase power flow of an under loaded line. The novelty of multi-winding transformer based power-flow controller is the use of unequal voltage ratio in the tap-changer windings of MWT with bi-directional switches to provide a compensating voltage required to achieve the desired power flow. This new model drastically increases the number of compensating points to make it more compact with higher flexibility. It aims to utilize the full potential of a line (bound by its thermal limits) to contribute in power flow by providing several times higher resolution with limited number of switches and reduced amount of copper and iron volume compared to existing state-of-the-art technology. The proposed MWT model has been included in Newton Raphson Load Flow (NRLF) method for power flow analysis. The feasibility of the model has been realized using a standard 5 bus test system and a modified IEEE 57 bus system. Operation of the PFC has been demonstrated using a hardware laboratory prototype for generating nearest compensating points (voltage vectors) corresponding to the obtained compensating voltages after load flow solution. The results obtained are verified by simulating the controller in MATLAB/Simulink.