Network reconfiguration and capacitor placement have been widely employed to reduce power losses and maintain voltage profiles within permissible limits in distribution systems. Reconfiguration method proposed in this paper is based on a simple branch exchange method of single loop. In this simple method of branch exchange, loops selection sequence affects the optimal configuration and the network loss. Therefore, this method has been improved by optimizing the sequence of loops selection for minimizing the energy losses in this paper. Also, a joint optimization algorithm is proposed for combining this improved method of reconfiguration and capacitor placement and therefore maximum loss reduction. For more practical application of the proposed method, different load patterns are considered and a fast method of total energy loss calculation is employed for the economic optimization of energy losses during the planning horizon. Discrete genetic algorithm (GA) is used to optimize the location and size of capacitors and the sequence of loops selection. In fact, the capacitor sizes have been considered as discrete variables. Simulated annealing (SA) is also applied to compare the performance of convergence. The proposed algorithm is effectively tested on a real life 77-bus distribution system with four different kinds of load patterns.

In this paper, a new method for optimum coordination of overcurrent relays is proposed. The proposed method is based on only constraints. Minimization is inherently included by setting the time dials to minimum and increasing their values gradually. Configuration changes of the network is taken into account. The method does not need any initial solution. It can consider both linear and nonlinear relay characteristics models. The optimal settings of overcurrent relays for 8-Bus and England Norweb networks are obtained and comparison between the new method and existing methods is made.

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This paper presents a new method to find minimum number of Phasor Measurement Units (PMUs), to determine the fault locations on transmission network lines in a power system. Considering the installation cost of PMUs, it is important to investigate the placement scheme of the PMUs at minimal locations on the network in the sense that the fault location observability can be achieved over the entire network. In this paper a new algorithm is introduced to find an optimization problem for determining the place and minimum number of PMUs in order to find accurate place of any fault in power systems. The accuracy of suggested algorithm is independent from the fault type and its resistance. Optimization problem is solved by branch and bond method. 41-bus 230kV Tehran Transmis sion Regional Electric Network is used as a real case study.

This paper proposed the new method to carry out the optimized allocation of the protection devices to improve SAIFI based on the current placement of devices. Genetic algorithm (GA) is used to optimize the objective function. Advantages of the method used in this paper are minimal risk to change the protection devices, cost minimization of change the location of the devices and system reliability improvement. In order to illustrate the application of this method, an actual electric power distribution feeder, 20 kV, overhead lines, threewire with a delta-grounded wye connection substation transformer is used.

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