The problem of capacitor placement on a radial distribution system is formulated and a solution algorithm is proposed. The location, type, and size of capacitors, voltage constraints, and load variations are considered. The objective of capacitor placement is peak power and energy loss reduction, taking into account the cost of the capacitors. The problem is formulated as a mixed integer programming problem. The power flows in the system are explicitly represented, and the voltage constraints are incorporated. A solution method has been implemented that decomposes the problem into a master problem and a slave problem. The master problem is used to determine the location of the capacitors. The slave problem is used by the master problem to determine the type and size of the capacitors placed on the system. In solving the slave problem, and efficient phase I-phase II algorithm is used. >

Optimal capacitor placement on radial distribution systems

A capacitor sizing problem for capacitors placed on a radial distribution system is formulated as a nonlinear programming problem, and a solution algorithm is developed. The object is to find the optimal size of the capacitors so that the power losses will be minimized for a given load profile while considering the cost of the capacitors. The formulation also incorporates the AC power flow model for the system and the voltage constraints. The solution algorithm developed for the capacitor sizing problem is based on a Phase I-Phase II feasible directions approach. Novel power flow equations and a solution method, called DistFlow, for radial distribution systems are introduced. The method is computationally efficient and numerically robust, especially for distribution systems with large r/x ratio branches. DistFlow is used repeatedly as a subroutine in the optimization algorithm for the capacitor sizing problem. The test results for the algorithm indicate that the method is computationally efficient and has good convergence characteristics. >

Optimal sizing of capacitors placed on a radial distribution system

In this paper, a new design methodology for determining the size, location, type and number of capacitors to be placed on a radial distribution system is presented. The objective is to minimize the peak power losses and the energy losses in the distribution system considering the capacitor cost. A sensitivity analysis based method is used to select the candidate locations for the capacitors. A new optimization method using a genetic algorithm is proposed to determine the optimal selection of capacitors. Test results have been presented along with the discussion of the algorithm. >

Optimal selection of capacitors for radial distribution systems using a genetic algorithm

The problem of capacitor allocation for loss reduction in electric distribution systems has been extensively researched over the past several decades. This paper describes the evolution of the research and provides an evaluation of the practicality and accuracy of the capacitor placement algorithms in the literature. The intent of this paper is not to provide a complete survey of all the literature in capacitor allocation, but to provide researchers and utility engineers further insight into the choices of available capacitor allocation techniques and their respective merits and shortcomings. Furthermore, this paper serves as a useful and practical guideline to assist in the implementation of an appropriate capacitor allocation technique.

Classification of capacitor allocation techniques

A novel formulation of the general capacitor placement problem taking into consideration practical aspects of capacitors, the load constraints, and the operational constraints at different load levels is presented. This formulation is a combinatorial optimization problem with a nondifferentiable objective function. A solution methodology based on an optimization technique (simulated annealing) is proposed to determine the locations where capacitors are to be installed, the types and sizes of capacitors to be installed, and the control settings of these capacitors at different load levels. The solution methodology can offer the global optimal solution for the general capacitor placement problem. >

Optimal capacitor placements in distribution systems. I. A new formulation and the overall problem

This paper reports the development of an analytical method to determine the best capacitor locations, reactive compensation level, and yearly loss reductions under a wide range of annual reactive load conditions for use in distribution system design. The results show that, not only is more than 80 percent yearly loss reduction possible with non-switched capacitor banks, but also optimum reacttve-compensation level and maximum yearly loss reduction can be expressed in a simple mathematical equation.

Analytical Method of Capacitor Allocation on Distribution Primary Feeders

This paper reports the development of a method which quantitatively defines the total cost of owning and operating the transformer where the total cost includes both the capital cost and loss cost as well as the cost incurred due to the increased loss-of-life of transformers due to overloading throughout the expected life of the transformler. The resul ts establish an appropriate transfornier loading policy for permissible loss of transformer life in terns of cost.

Y. G. Bae

Papers

Analytical Method of Capacitor Allocation on Distribution Primary Feeders

Quantitative Evaluation of the Cost and Benefits Associated with Transformer Loading