EP Based Optimal Power Flow Solutions

Abstract

The objective of the work presented in this report is to make an EP based algorithm for solving the optimal power flow (OPF) problem without and with compensating device. The objective in the OPF problem formulation is the minimization of total cost of real power generation. The proposed method solves the OPF problem subject to the power balance equality constraints, limits on the control variables namely active power generations, controllable voltage magnitudes, limits on the dependent variables namely reactive power generations and load bus voltage magnitudes and limits on MVA line flows as the inequality constraints. The individual cost of each generating unit is assumed to be function, only of active power generation and are represented by quadratic curves of second order. Earlier, a wide variety of optimization techniques have been applied to solving the OPF problems such as nonlinear programming (NLP), quadratic programming (QP), linear programming, Newton-based techniques, and interior point methods. But, because of certain drawbacks, such as insecure convergence properties, algorithmic complexity, and convergence characteristics. These, local optimization techniques are not suitable for such a problem. Moreover, there is no local criterion to decide whether a local solution is also the global solution. Therefore, conventional optimization methods that make use of derivatives and gradients, in general, are not able to locate or identify the global optimum. Hence, it becomes essential to develop optimization techniques that are efficient to overcome these drawbacks and handle such difficulties. Thus, heuristic algorithm i.e. evolutionary programming, has been proposed for solving the OPF problem. The OPF solution is obtained using EP for the IEEE-30 bus system. The compensating device is also included in the power system network to study its role or its impact on the power system network. The compensating device included in this study is the series capacitor. The role of series capacitor used here in the problem is to improve the power transfer capability of the line while keeping a marginal variation in cost.