Capacitor Placement In Distribution Systems Research Articles

Distribution system reliability enhancement using optimal capacitor placement

Failure statistics of most utilities indicate that distribution systems make the greatest individual contribution to the unavailability of supply to customers. Optimal capacitor placement in distribution systems has a number of advantages such as reducing losses, improving voltage profile, improving power factor and so on. The conventional objective function of the optimal capacitor placement consists of the total cost of losses and investments. Since capacitors supply reactive loads locally, they improve the load-carrying capability of the lines and therefore play the same role as redundant lines. Thus, optimal capacitor placement can also improve the reliability indices of a distribution system. Therefore two new objective functions are defined here. The first one is defined as the sum of reliability cost and investment cost. The second is defined by adding the reliability cost, cost of losses and investment cost. The latter is a comprehensive objective function which is the resultant of the conventional and reliability-based objective functions. This problem is solved using a particle swarm optimisation-based algorithm. The effectiveness and applicability of the proposed approach are examined using a distribution network.

Optimal capacitor placement in distribution systems using a combination fuzzy-GA method

This work presents a combination fuzzy-GA method to resolve the capacitor placement problem. The problem formulation considers three distinct objective functions related to minimize the total cost for energy loss and capacitors to be installed, as well as decreasing the deviation of bus voltage and improving the margin loading of feeders. The novel formulation is a multi-objective and non-differentiable optimization problem. These objective functions are first formulated in fuzzy sets to assess their imprecise nature before introducing a fuzzy satisfying method based on the GA to derive the optimal solution. The proposed approach is implemented in a software package and its effectiveness is verified through numerical examples on the Tai-power system.

Effects of unbalances and harmonics on optimal capacitor placement in distribution system

A method comprising of heuristic search technique and simulated annealing (SA) has been proposed for solving the problem of optimal capacitor placement in radial distribution system and the effects of network and load unbalances, supply harmonics and load non-linearities have been studied. The effect of network unbalances is most severe and can be incorporated very easily. But a new formulation of the problem is needed to include the effects of load unbalances, supply harmonics and load non-linearities as these are uncertain in nature.

Optimal capacitor allocation in distribution systems using a genetic algorithm and a fast energy loss computation technique

This paper presents a new approach to shunt capacitor placement in distribution systems having customers with different load patterns. The allocation of capacitors is considered in a system comprising a network of feeders fed from an upstream equivalent transmission system through a substation transformer. The benefits of capacitor placement, such as the system capacity release and reduction of overall power and energy losses, are considered. The fast method of total energy loss calculation based on the computation of the moments of normalized daily load curves is used to calculate the annual energy loss reduction. An example of optimal capacitor allocation in a distribution system is presented in which customers with commercial, urban residential, rural and light industrial load patterns are considered.

An approximate method for capacitor placement in distribution system using heuristics and greedy search technique

Abstract A new method based on heuristics and greedy search technique has been reported in this paper for the placement of capacitors in radial distribution system. Heuristic rules have been developed to determine the probable capacitor locations in a distribution network. A greedy search technique then determines the optimum capacitor locations from these probable locations and the size of capacitors at these locations. The greedy search technique for the determination of the optimum locations and size of capacitors is based on a simple one dimensional search technique called the basic search technique in this paper. This basic search technique has also been used successfully as an additional operator of the genetic search technique to develop a GA based solution of the capacitor placement problem in distribution system.

Optimal capacitor placement in distribution systems by genetic algorithm

The genetic algorithm uses a biological analogy to evolve a population of search-space points toward an optimal solution, and has been applied to several disiplines in engineering and the sciences. The algorithm is attractive due to its ease of implementation, its lack of differentiability requirements on the objective function, and, its ability to find globally optimal solutions. These properties allow optimization of a practical formulation of the capacitor placement problem which includes the discrete nature of capacitor installations. In this paper, the genetic algorithm's structure, its application to the capacitor placement problem in distribution systems, and experimental numerical results are presented. Additionally, several implementation issues including selection pressure, fitness scaling and ranking, unity crossover probability, and the selection of generalized control parameters are examined in details.