Voltage Profile Improvement by Capacitor Placement and Control in Unbalanced Distribution Systems Using Differential Evolution Algorithm

Abstract

ABSTRACT:One of the most important methods in loss reduction and controlling the voltages of distribution systems is the utilization of the fixed and switched capacitors. To do this, real modelling of the system in actual operational conditions including unbalanced or balanced loading and for actual feeder structure, ie, radial/meshed configuration, are required. In this paper, a new technique for finding the optimal values of the fixed and switched capacitors in the distribution networks with above properties based on the differential evolution algorithm is presented. For this purpose, the modelling of the loads at different load levels are simulated with low voltage and medium voltage capacitors that are available on the market. Regarding the above factors in addition to the various parameters in the optimization problem, DE Algorithm is used to find the best and real optimal network with the best rate for the capacitors.KEYWORDS: unbalanced distribution networks, ,DE Algorithm, capacitor placement, fuzzy expert system. I.INTRODUCTIONOne of the most effective and useful methods in re-ducing the power losses of distribution networks is uti-lization of optimal capacitor placement. By using shunt capacitors, the reactive power needed for loads is pro-vided so that besides the reduction of losses the voltage profile of nodes is also improved. There are, of course, nu-merous difficulties in optimal placement of capacitors in the purpose of reducing losses. These problems include: a) non-clarity of the behavior of feeders' loads, particularly domestic loads, b) complexity of distribution net-works, c) uncertainty of electric distribution companies in returning the initial capital expenditure used for capaci-tor placement and d) variety of the type of network loads. With due regard to these difficulties, in many researches made so far, some assumptions in capacitor placements have been considered to solve the problem in a more simple method [1-18], which have not been appealing to distribution companies, so that the losses are still high in the network. Most of the consumption loads in distribution net-works are single phase domestic loads which are unbalanced. Therefore, it is useful to investigate the capacitor placement for unbalanced distribution networks [1][2][3]. However, it has not been regarded in most of the previous works [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. On the other hand, in the methods presented in [6][7][8][9][10][11][12][13][14][15]17] the loss reduction has been accomplished only by using the fixed capacitors. Moreover, in many previous methods, the medium voltage capacitors which are more expensive than low voltage ones are used [2,3,[5][6][7][8][9][10][11][12][13][14][15][16][17][18].One of the important issues in the placement of capacitors is considering the load variations of the network. In some methods of load variation has been considered at several different levels, and in some other methods [1,[6][7][8][9][10][11][12][13][14]18], it has not been considered at all, and ...

Optimal Placement and Sizing of Unified Power Quality Conditioner on Ieee 33 Bus Using Moth Flame Optimization Algorithm

“…A UPQC is the focus of this research work. The main purpose of the UPQC is to compensate for supply voltage, reactive power, negativesequence current, and harmonics [10,11,12]. In other words, the UPQC has the capability of improving power quality at the point of installation on power distribution systems.…”

Distribution Feeder Loss Optimization: A Case Study

“…A fuzzy-based genetic algorithm is used to find the optimal location for capacitors. A novel capacitor allocation and control method in an unbalanced distributed network is proposed using a differential evaluation algorithm [8]. Allocation of both fixed and switched capacitor is presented.…”

Improvement of Power Delivery Efficiency of 11KV Power Line using Power Capacitor Placement

“…That is, reactive power compensation can effectively improve power quality by reducing the line losses so as to improve the efficiency of the power network. In this way, distribution capacity of the lines is increased and the output of generator and transformer is also enhanced and the system may acquire longer life span and has greater reliability [11], [12], [13]. Capacitor placement in power network has two major concerns in it.…”