Utilization performance based FACTS devices installation strategy for transmission loadability enhancement

Two types of FACTS devices, SVC and TCSC, can be installed on buses and transmission lines to enhance the transmission loadability (TL) of power systems, respectively through injecting reactive power and changing line reactance. In this paper, there are three main steps in the FACTS devices installation strategy proposed. In step 1, based on the peak-load state, the CPF technique is used to formulate the maximum transmission loadability (MTL) problem to maximize the TL increased from the peak-load through installation of the FACTS devices. Here, the MTL without FACTS device installed is first calculated. While in step 2, based on the power flow solution for the MTL obtained in step 1, the positions proper to place SVCs and TCSCs are determined using the tangent vector technique and real power flow performance index (PI) sensitivity factors, respectively. Various FACTS devices installation schemes are then built with these candidate positions and, for each scheme, the MTL is solved by determining the ratings for the SVCs and TCSCs installed. Finally in step 3, by comparing the ratios of the investment costs to the TLs increased between various schemes, a correspondingly most advantageous scheme is suggested. Also, to further validate the effectiveness of the proposed method, a static voltage stability analysis is given.