State Estimation and Volt-Var Control in Smart Distribution Grid

Distribution smart grid is very important part of the smart grid. Utilities use Distribution Management System (DMS) as supervisory control layer at the power system control centers. State Estimation (SE) and Volt-Var Control (VVC) are the prime applications of the DMS. In the modern DMS, SE is required for extensive monitoring and control of the entire distribution network. In the presence of Distributed Generators (DGs) such as solar, wind, micro turbines, fuel cells etc. to maintain voltage level in the prescribed limits and control of bidirectional flow of reactive power with minimized distribution power losses is a great challenge. Previously proposed methods to optimize SE and VVC presume that objective function equations are continuous and differentiable. However, the practical equipment installed in the distribution network i.e. on load tap changer transformers, DGs, voltage regulators etc. have nonlinear characteristics which result in nonlinear objective functions of SE and VVC. Moreover, the objective functions are discontinuous due to discontinuous tap changing of transformers. Therefore, the conventional methods cannot be applied to nonlinear optimization problems. To solve the nonlinear optimization problems, recently proposed heuristic algorithms are very effective. In this paper, Artificial Bee Colony (ABC) algorithm has been implemented to optimize SE and VVC