Studies On Switching Control Algorithms For Capacitors In Distribution Networks

Two network analysis and operation algorithms for balanced radial distribution systems, called forward-backward sweeping method of power flow solution and real-time control of capacitors installed on distribution systems, are presented in this thesis. Distribution networks have characteristics such as mesh network on planning and radial networks on operation. The radial topology of distribution networks has been fuiiy exploited such that a systematic branch and node numbering scheme is utilized to achieve storage and computational economy. Using Kirchoffs voltage law, a set of simple algebraic iterative power flow equations has been developed to conduct the power flow studies, called forward-backward sweeping method. Studies on some distribution test systems show the power flow analysis of distribution systems to have the superior performance in terms of solution time and convergence characteristics. The thesis proposes two algorithms for real-time switching control scheme of shunt capacitors. One is fuzzy control based algorithm. The response characteristic plane is obtained from studies of the fuzzy control system for switching control of capacitors installed on distribution systems. It improves on preventing the switching control process from oscillation and refusing compensation. The other is optimal switching control of the multi-tap capacitors formulated by nonlinear hybrid integer programming model. Successive linear programming is proposed to solve it with the help of Lindo6. 1 program. Digital tests are carried out and results show that the algorithm is practical and efficient for distribution systems loss minimization and can be used to optimize real distribution system operation.