OPTIMAL SIZE AND LOCATION OF SVC DEVICES CONSIDERING VOLTAGE STABILITY CONSTRAINTS: A MIXED-INTEGER NONLINEAR PROGRAMMING APPROACH

Abstract

Due to the rapid growth of load, the deregulation of the electricity sector as well as the increasing penetration of renewable energy sources, the power system’s operating point is likely to be close to the stability limit, especially the voltage stability limit. Therefore, guaranteeing an appropriate distance from the current operating point to the voltage collapse plays an important role in the planning and operation problem. This paper presents a Mixed-Integer Nonlinear Programming (MINLP) model to optimize the location and capacity of Static Var Compensator (SVC) devices with the purpose of enhancing the system voltage stability. The objective function of this optimization problem is to minimize the total cost, including the investment cost of SVC and the cost of network energy loss. The optimization problem’s constraints are represented for both current and critical loading conditions. The proposed MINLP formulation is evaluated on a modified IEEE 30-bus system with different scenarios of minimum security level and demand power value using XPRESS commercial solver under the GAMS programming language. The calculation results reveal that the minimum security level pertaining to the system voltage stability and load demand level significantly affect the optimal location and size of SVC devices.