Capacitor Banks In Distribution Systems Research Articles

Optimal Allocation of Distributed Generations and Capacitor Banks in Distribution Systems Using Arithmetic Optimization Algorithm

In this paper, an optimization approach based on an arithmetic optimization algorithm (AOA) is proposed for specifying the optimal allocation of distribution generations/generators (DGs) and capacitor banks (CBs) in radial distribution systems. The AOA is a new population-based meta-heuristic algorithm that is essentially based on using basic arithmetic operators in mathematics. The proposed approach is employed to specify the optimum placement, capacity, and power factor of DGs and CBs to decrease the distribution systems’ total power loss and voltage deviation. To state the performance of the proposed approach, DGs and CBs are placed in IEEE 33-bus and 69-bus systems separately or together. When only DGs are used and the parameters of location, capacity, and power factor of DGs are determined simultaneously, the total active power loss reductions in the IEEE 33-bus and 69-bus systems are achieved at 94.42% and 98.03%, respectively. When the results of other optimization algorithms are examined, it is seen that better results are obtained with AOA.

Optimal Allocation and Sizing of Capacitor Banks in Distribution System to Reduce the Power Loss Using Beluga Whale Optimization

One portion of the distribution system is the distribution feeder. Buses carrying more loads and having long‐distance route lines are significant problems due to the presence of power loss and the increase in the overall cost of the transportation process. Hence, the overall power loss minimization is taken as the major objective. The best sizing and allocation of capacitors in a bank in the distribution line are used to minimize the total loss. BWO technique is utilized in this optimization process. The backward‐forward sweep load flow is used for the computation of the power flow in MATLAB. The sensitive buses have been chosen according to the factor of loss sensitivity (LSF) and using BWO. The validity of the test has been made on the standard IEEE 34 and 85 bus radial distribution system. The simulation results in the 34‐bus radial system are much different from the results of PSO, GWO, WO, and IWO. In the 85‐bus radial system, the results are seen with the outcomes of PSO, WO, and BFOA. In both cases, the results of the proposed technique are found to be better than the existing methods. Therefore, the result shows that BWO can be effective for future selection to improve large distribution networks by sizing and locating the capacitors optimally.

A Novel Framework for Operation of Capacitor Banks in Non/Semi/Fully-Automated Distribution Networks

Nowadays, distribution systems have different levels of automation due to the need for massive investment. The optimal operation of capacitor banks (CBs) is a widely-used approach to improve the performance of these systems. Therefore, the optimal operation of CBs in distribution systems with any level of automation is essential. This paper introduces a novel framework for the operation of CBs in the non/semi/fully-automated distribution networks based on two timescales of day-ahead and near-to-real-time applications. In this framework, the linear current injection power flow method to properly study CB effects on the system is developed, including i) modeling vector group transformer, ii) modeling induction motors, iii) plotting the PV curve of motor loads as indices to assess the efficiency of CB on the voltage system, and iv) developing a fast power flow method with a low computational burden. Besides, the optimization problem of CBs control as the core of the proposed framework is reformulated, considering the level of network automation. The accuracy of the developed framework is evaluated on the IEEE 37-bus and 123-bus test systems. The obtained results verify the efficiency and superiority of the proposed framework.

Optimal allocation of capacitor banks in distribution systems using particle swarm optimization algorithm with time-varying acceleration coefficients in the presence of voltage-dependent loads

ABSTRACT In this paper, a novel solution algorithm is presented for the capacitor allocation problem in radial distribution systems according to the type of load model with the primary objective of power loss minimisation and network savings maximisation. The voltage-dependent load model considers three types of demands, namely industrial, residential, and commercial. Loss sensitivity factors and particle swarm optimisation with time-varying acceleration coefficients (TVAC-PSO) are employed to optimise the location and size of the capacitors, respectively. The loss sensitivity factors identify the sequence of buses to be compensated by the placement of capacitors. The feasibility of the presented method is evaluated on standard 34 and 85-bus radial distribution systems. The results of the comparative study suggest that our proposed algorithm outperforms the existing heuristic techniques in solution quality and convergence speed, which renders it viable and applicable for implementation.

Optimal Sizing and Placement of Capacitor Banks in Distribution Networks Using a Genetic Algorithm

Nowadays, response to electricity consumption growth is mainly supported by efficiency; therefore, this is the new main goal in the development of electric distribution networks, which must fully comply with the system’s constraints. In recent decades, the issue of independent reactive power services, including the optimal placement of capacitors in the grid due to the restructuring of the electricity industry and the creation of a competitive electricity market, has received attention from related companies. In this context, a genetic algorithm is proposed for optimal planning of capacitor banks. A case study derived from a real network, considering the application of suitable daily profiles for loads and generators, to obtain a better representation of the electrical conditions, is discussed in the present paper. The results confirmed that some placement solutions can be obtained with a good compromise between costs and benefits; the adopted benefits are energy losses and power factor infringements, taking into account the network technical limits. The feasibility and effectiveness of the proposed algorithm for optimal placement and sizing of capacitor banks in distribution systems, with the definition of a suitable control pattern, have been proved.

Allocation of distributed generation and capacitor banks in distribution system

<p>Voltage profile and power losses on the distribution system is a function of real and imaginary power loading condition. This can be effectively managed through the controlled real and reactive power flow by optimal placement of capacitor banks (CB) and distributed generators (DG). This paper presents adaptive Particle Swarm Optimization (MPSO) to efficiently tackle the problem of simultaneous allocation of DG and CB in radial distribution system to revamp voltage magnitude and reduce power losses. The modification to the conventional PSO was achieved by replacing the inertial weight equation (W) in the velocity update equation base on the particle best experience in the previous iteration. The inertial weight equation is designed to vary with respect to the iteration value in the algorithm. The proposed method was investigated on IEEE 30-bus, 33-bus and 69-bus test distribution systems. The results shows a significant improvement in the rate of convergence of APSO, improved voltage profile and loss reduction.</p>

Optimal Allocation of Renewable Distributed Generation and Capacitor Banks in Distribution Systems using Salp Swarm Algorithm

Recent advances in power generation technologies using renewable energy resources, changes in utility infrastructure and government policies tend to increase the interest in a renewable-based distributed generation units (DGs) in a distribution system. To obtain reduced power loss, voltage deviation and improved bus voltage stability in distribution systems, it is mandatory to control optimal power flow of both active and reactive power. Therefore, optimal allocation of DGs and CBs plays a vital role in distribution systems performance enhancement. Where optimal allocation of DGs reduce active power loss and optimal allocation of capacitor banks (CBs) improve bus voltages. This paper proposes a salp swarm algorithm (SSA) for optimal allocation of DGs and CBs. The main aim of the proposed algorithm is to attain technical, economic and environmental benefits. The proposed algorithm is based on the salps swarming behavior in oceans when navigating and foraging. To assess the performance of the proposed SSA three different cases considered: optimal allocation of only DGs, only CBs and simultaneous DGs and CBs. The proposed algorithm is tested on IEEE 33 and 69 bus radial distribution systems. The simulated results illustrate the efficiency of the proposed algorithm when compared to other existing optimization algorithms. Also, the proposed algorithm has achieved technical benefits of reduced power loss, voltage deviation, and improved bus voltage stability, the economic benefit of reduced total electrical energy cost and environmental benefit of reduced emissions.

Optimal Placement and Sizing of Distributed Generation and Capacitor Banks in Distribution Systems Using Water Cycle Algorithm

Integration of distributed generation units (DGs) and capacitor banks (CBs) in distribution systems aim to enhance the system performance. This paper proposes water cycle algorithm (WCA) for optimal placement and sizing of DGs and CBs. The proposed method aims to achieve technical, economic, and environmental benefits. Different objective functions: minimizing power losses, voltage deviation, total electrical energy cost, total emissions produced by generation sources and improving the voltage stability index are considered. WCA emulates the water flow cycle from streams to rivers and from rivers to sea. Five different operational cases are considered to assess the performance of the proposed methodology. Simulations are carried out on three distribution systems, namely IEEE 33-bus, 69-bus test systems, and East Delta network, as a real part of Egyptian system. The simulated results demonstrate the effectiveness of the proposed method compared with other optimization algorithms. Also, the results demonstrate that the proposed WCA gives superior performance for the system and give distinguished improvements in both economic and environmental benefits. Moreover, the results give the flexible operation with controllable power factor DGs that is better than those using DGs at fixed power factor.

Improving Reliability and Reducing Power Loss in Power Distribution Network by Determining Optimal Location and Size of Capacitor Banks

The use of capacitor banks in distribution system has many outstanding usages include improving the power factor of a system, voltage profile, and reliability besides the reducing of the power flow losses of the component’s reactive due to the compensation. These benefits depend greatly on how capacitors are placed in the distribution system. Hence, in order to achieve the high reliable construction, switching capacitor has been placed to improve the main challenges of the network designing (reliability and reduce power loss) in the radial distribution system. As regards, the importance of the reliability and power losses are ignored in the distribution networks; the aim of this paper is primarily to establish an objective function for the parallel optimization of these aforementioned parameters. In the simulation process, ten parameters have been compared, which are: System Average Interruption Frequent Index (SAIFI) and its cost, System Average Interruption Duration Index (SAIDI) and its cost, power loss and its cost, the installed capacity and it's cost and values of two objective functions. Honey-bee mating optimization (HBMO) algorithm has been used to solve this problem. Then, the developed technique has been used on the IEEE standard distribution network as a problem-solving system.

Switching Control for Capacitor Banks in Distribution System

Objectives: A shunt capacitor bank with appropriate switching control using relay and circuit breakers is proposed to compensate reactive power in an 11kV Malaysian test distribution system with high density commercial load. Methods: Fuseless Capacitor Bank will be modelled according to IEEE standard using MATLAB. The designed switching control for the fuseless capacitor bank will perform condition checking based on the criteria of power factor and determine the best control action to be taken in order to compensate reactive power in the power system effectively. The designed system is then tested on an 11kV Malaysian test distribution system with high density commercial load. Findings: Simulation results clearly indicate that the designed system is able to react and compensate reactive power adequately in accordance to Malaysia’s utility regulations. Improvements: For future improvements, criteria focused on both voltage and power factor can be implemented to minimize power loss in the system.

A Simultaneous Biogeography based Optimal Placement of DG Units and Capacitor Banks in Distribution Systems with Nonlinear Loads

Abstract This paper uses a new algorithm namely biogeography based optimization (BBO) intended for the simultaneous placement of the distributed generation (DG) units and the capacitor banks in the distribution network. The procedure of optimization has been conducted in the presence of nonlinear loads (a cause of harmonic injection). The purpose of simultaneous optimal placement of the DG and the capacitor is the reduction of active and reactive losses. The difference in the values of loss reduction at different levels of the load have been included in the objective function and the considered objective function includes the constraints of voltage, size and the number of DG units and capacitor banks and the allowable range of the total harmonic distortion (THD) of the total voltage in accordance with the IEEE 519 standards. In this paper the placement has been performed on two load types ie constant and mixed power, moreover the effects of load models on the results and the effects of optimal placement on reduction of the THD levels have also been analyzed. The mentioned cases have been studied on a 33 bus radial distribution system.

Optimal Distributed Generation and Reactive Power Allocation in Electrical Distribution Systems

Optimal and simultaneous siting and sizing of distributed generators and capacitor banks in distribution systems have attracted a lot of attention from distribution companies. The placement and capacity of these devices have direct effects on the system’s performance. This paper presents a model for the simultaneous allocation of capacitor banks and distributed generation, which takes into account the stochastic nature of distributed generation. To solve the model presented, we propose an efficient hybrid method based on Tabu search and genetic algorithms. The hybrid method is applied to a well-known system in literature.

An Approach for Optimal Allocation of Fixed and Switched Capacitor Banks in Distribution Systems Based on the Monkey Search Optimization Method

This work presents an algorithm based on the bio-inspired optimization technique known as monkey search (MS) for the optimal allocation of fixed and switched capacitor banks in distribution systems. The objectives are to minimize the energy loss, to improve the voltage levels and to reduce the carbon dioxide emission. The monkey search technique is a metaheuristic method that is inspired by the behavior of a monkey searching for food in a jungle. The applied method consists of a modified monkey search (MMS), which presents modifications and improvements for the original MS technique to represent in a suitable manner the features and constraints of the capacitor allocation problem. The proposed model considers different load levels, voltage limit constraints and practical values for fixed and switched capacitor banks, as well as for unit costs and emission coefficient. Case studies are performed by using test systems of the literature in order to assess the efficiency of the proposed algorithm, including a tutorial on the MMS algorithm.

Allocation of capacitor banks in distribution systems through a modified monkey search optimization technique

Abstract This work presents a methodology for the allocation of fixed capacitor banks in electrical power distribution systems by applying a bio-inspired optimization technique. The goal is to optimize the distribution network operation over a planning horizon by minimizing the system losses with minimum cost of investment in capacitors. For this aim to be achieved, this work proposes improvements to the Monkey Search optimization technique to achieve a better representation of the capacitor allocation problem and to increase the computational efficiency. Distribution systems that are widespread in the literature are used to evaluate the proposed methodology.

Automatic capacitor bank identification in power distribution systems

Tracking the performance and health of capacitor banks in distribution systems is a challenging task due to their high number and the widespread geographical distribution of feeder circuits. In this work we propose a signal processing technique capable of identifying and characterizing the number of capacitor banks connected to a standard North-American feeder circuit. The way the technique is applied allows a real-time remote monitoring of their operation, automatically identifying the switching activity for each capacitor bank connected. The technique is based on an unsupervised clustering of the three phase reactance step magnitudes. We demonstrate that using only passive monitoring of conventional substation bus PTs and feeder CTs, without any communication, nor visual inspection, to individual banks, it is possible to predict the number of capacitor banks on the distribution feeder and track their performance and activity over time.

Optimal Capacitor Placement to Distribution Transformers for Power Loss Reduction in Radial Distribution Systems

Deploying shunt capacitor banks in distribution systems can effectively reduce the power loss and provide additional benefits for system operation. In practice, the power loss on distribution transformers can account for a considerable portion of the overall loss. This paper proposes a method for optimal placement of capacitor banks to the distribution transformers to reduce power loss. The capacitor bank locations are considered at the low-side of transformers. The net present value (NPV) criterion is adopted to evaluate the cost benefit of the capacitor installation project. First, an explicit formula for directly calculating the power loss of radial distribution systems is derived. Then, the optimal capacitor bank placement is formulated as a mixed-integer programming (MIP) model maximizing the NPV of the project subject to certain constraints. The model is suitable for being solved by commercial MIP packages, and the operational control of the capacitor banks to maximize the power loss reduction can be simply achieved by local automatic switching according to VAR measurements. The proposed method has been practically applied in the Macau distribution system, and the simulation results show that the proposed method is computationally efficient, and a considerable positive NPV can be obtained from the optimal capacitor bank placement.

A New Method for Online Determination of the Location of Switched Capacitor Banks in Distribution Systems

This paper describes two new approaches for the determination of the direction of switched capacitor banks as well as an efficient technique for estimating the distance of switched capacitors from the monitoring location in distribution systems. At first, two new indices based on branch voltage and current changes immediately after the capacitor switching instant are proposed for determining the direction of switched capacitor banks. The wavelet transform is used to detect the exact instant of switching. Then, a new technique based on linear circuit theory is proposed to estimate the distance of the switched capacitor bank from the monitoring location using capacitor switching transient data. Simulation results show that the error of the estimated distance is acceptable. A combination of the approaches for direction finding and the technique for distance estimation provide a novel method for determining the location of switched capacitor banks in real distribution systems. The method is valid in all normal, back-to-back, and abnormal switching of wye- and delta-configured capacitor banks. Also, the size of the capacitor bank has no effect on method accuracy. The efficacy of the proposed method is validated by using the IEEE 13-bus and 34-bus distribution systems.

TRANSIENT ANALYSIS OF CAPACITOR SWITCHING IN UNBALANCED DISTRIBUTION SYSTEM WITH HARMONIC DISTORTION

ABSTRACT The wide application of shunt capacitor banks in distribution systems for economic reasons, have raised concern about over-voltage transients and harmonic magnification in unbalanced distribution systems. This paper introduces a new method for transient analysis during capacitor switching. Presence of harmonic sources, unbalance in feeder configuration, and combinations of single-and three-phase loads are accounted for. The new method is a frequency domain-based approach using a three-phase Z-Bus algorithm. The paper reviews the concepts of the building algorithm of a three-phase Z-bus matrix in the complex frequency domain. Untransposed feeders and different types of loads are considered. Finally, the boundary conditions for different capacitor switching cases and the results with harmonic distortion are reported.