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This paper presents a Cuckoo Search (CS) algorithm-based methodology for simultaneous optimal placement and sizing of Shunt Capacitors (SCs) and Distributed Generations (DGs) together in radial distribution systems. The objectives of the work are to minimize the real power and reactive power losses while maximizing the voltage stability index of the distribution network subjected to equality and inequality constraints. Different operational test cases are considered namely installation of SCs only, DGs only, SCs before DGs, DGs before SCs, and SCs and DGs at one time. The proposed method has been demonstrated on standard IEEE 33-bus and a practical Ayepe 34-bus radial distribution test systems. The highest percentage power loss reduction of 94.4% and other substantial benefits are obtained when SCs and DGs are optimally installed simultaneously. Simulated results obtained from the proposed technique are compared with other well-known optimization algorithms and found to be more effective.

This paper introduces a smart coordinated allocation of distributed generation (DG) units, shunt-connected capacitors (SC), and static VAR compensators (SVC) for power loss minimization. The proble...

This paper proposes a novel approach to determine an optimal location and sizing of shunt capacitors for reactive power compensation in distribution systems with distributed generation. Here, the optimal location for installing the shunt capacitors is determined using the loss sensitivity factor approach. The stochastic nature of distributed generation (i.e., wind and solar PV powers) has been considered in this paper. Optimal sizing of shunt capacitors has been determined by considering the power loss minimization as objective function and this problem is solved using the differential evolution algorithm (DEA). The results obtained with DEA are also compared with genetic algorithm (GA) and particle swarm optimization (PSO) algorithms. The effectiveness of this proposed approach has been simulated on the IEEE 15, 33, 69 and 85 bus test systems.

This paper proposes a novel control method for the shunt capacitor equipped with a series inverter (ISC) in order to use with existing shunt capacitors in parallel. The proposed method controls the equivalent impedance of the ISC in the normal operation range to be equal to the conventional shunt capacitors equipped with a series inductor (LSC). The control increases the impedance to enhance its harmonic compatibility when the harmonic voltage increases beyond the normal operation range. Simulation results verify that the proposed ISC can compensate harmonic current together with the existing 6% LSC. In addition, the ISC can avoid its overcurrent even if it is used with the resonant condition by the existing shunt capacitor. This paper also investigates the circuit design for satisfying both harmonic compensation effect of the 6% LSC and the harmonic compatibility of the 13% LSC. The required dc voltage in the series inverter is 13% of the rated line-to-lime voltage. Thus, the capacity of the series inverter is much smaller than the total compensation capacity of the shunt capacitor.

For a conventional islanded microgrid, each distributed generation (DG) unit usually equips with an LC filter and a closed-loop filter capacitor voltage control is applied to ensure an accurate tracking of DG voltage. In this article, a cost reduction microgrid and DG units configuration is developed via the following two steps. First, an L -type filter is adopted by each DG unit and a centralized shunt capacitor is placed at point of common coupling (PCC). Then, the inherent synchronization feature of droop control is further exploited as an inherent synchronizer to identify the carrier angle relationships between parallel inverters, but without any communications between them. With the carrier information obtained, a decentralized interleaving pulsewidth modulation (PWM) among parallel inverter can be easily achieved via a slow proportional integral (PI) regulation of each DG unit relative carrier. Accordingly, the high-frequency switching harmonics of PCC voltage are suppressed even with simplified and size reduced DG output chokes. Second, a virtual impedance control is applied to DG units to cancel the voltage drops on the DG feeder in a direct PWM manner. Accordingly, mitigating the low-order harmonic PCC voltages is obtained without using any closed-loop voltage tracking at DG unit local processor. Comparative experimental results have been provided to validate the correctness of the proposed method.

For multiple-receiver wireless power transfer (WPT), a scalable solution is desired that functions with changing number of receivers. Meanwhile, challenges lie in differences in load characteristics, power level, and cross coupling between the receivers. This article employs Class E $\bf ^2$ dc–dc converter topology for the multiple-receiver WPT systems working at megahertz (MHz). The shunt capacitor capacitances of the Class E rectifiers and magnitude of constant output current of the current-mode Class E power amplifier are chosen as design parameters aiming at decoupling the received power of each receiver. Design procedures are developed to simultaneously achieve high efficiency and desired individual load powers over a target variation range of the cross coupling. An experimental 6.78-MHz three-receiver WPT system is optimally designed. The system is shown to be capable of providing different target load powers (10, 8, and 6 W) and maintaining a high system efficiency (above 70%) with different combinations and positions of the receivers.

This work aims at reduction in active and reactive power loss reduction in distribution networks as well as to improve the voltage stability of the networks. Optimum Distributed Generation (DG) placement and sizing is carried out in conjunction with shunt capacitor placement and sizing to determine the appropriate sizes of DG units and Capacitor banks to be placed in the networks so as not to violate certain constraints. The optimal sizes of the DG units and capacitor banks were obtained on application of a Cuckoo Search Optimization Algorithm while computations for Voltage stability was performed using the Voltage Stability Index (VSI). The obtained optimal sizes of DG units and Capacitors were individually and simultaneously placed on the distribution networks to ascertain the behaviour of the networks prior to and after their placements. The performance factors considered are power loss and voltage stability. A comparison of these performance factors under separate and simultaneous placement method was demonstrated using IEEE 33 and 69 test buses. Result show that power loss (active and reactive) reduced by 63.29% and 59.38% respectively for 33 bus system, with a 74.29% and 79.19% reduction on 69 bus system. Voltage stability also increased by 7.89% and 3.79% respectively for 33 and 69 bus system relative to values obtained for base case and separate DG and shunt capacitor placement. Keywords: Distributed generation, shunt capacitor, Cuckoo Search Algorithm (CSA), power loss and voltage stability.

Recently, integration of distributed generations (DGs) and shunt capacitors in radial distribution network are becoming popular to withstand the rapidly increasing in electricity demands. In this a...

In power quality (PQ) problems, the flexible AC transmission system (FACTS) devices have been developed the real power and reducing the PQ issues of the power system. Here the PQ analysis in photovoltaic (PV), wind turbine (WT) system with grid integrated static switched filter compensator (SSFC) is controlled by adaptive technique. The adaptive technique works with the combined process of Cuttle fish algorithm (CFA) and recurrent neural network (RNN) algorithm. The proposed adaptive technique is controlling the irregular switching process of the shunt capacitor banks of a tuned arm filter in SSFC device. The novelty of the proposed technique is improved for energy efficiency and demand management in grid utilization process. Here a power injection model of SSFC is considered to control the real power flow control in terms of grid utilization. The switching process is controlled by balancing control signal generated with the help of pulse width modulation (PWM) process. To modulate the PWM is used by two regulators, which is based on a tri-loop real error managed combined weighted adjusted proportional integral derivative controller. The proposed SSFC system is designed and implemented in MATLAB/Simulink platforms and the performance is validated with some existing devices such as unified power flow controller and SSFC devices.

This paper introduces the load flow on the Egypt Electricity Network system. The effect of capacitor compensation has been studied from three points. First, the problem of the series capacitor compensation was considered. The second type of compensation considered is shunt compensation. Finally, a mixed of shunt and series capacitors compensation was implemented. The analysis results were discussed based on the maximum reduction in the generated MVAR. The load variation is accounted for by considering three different load levels classified as light, medium and peak load with pre-specified durations. When solving the capacitor placement problem, the number, size, location and control settings of the capacitors at different load levels were determined. The load flow program is solved by the Power World Simulator (PWS) software. The results of series capacitor, shunt capacitor, and mixed compensation were studied. The investigation has been done for single capacitor and multi-capacitor compensation. Both 500kV and 220kV overhead lines have been considered.

As the penetration of distributed wind power in the distribution network continues to increase, the uncertainty of its output has a serious impact on the stable operation of the distribution network. It is difficult to meet the voltage regulation requirements when the wind power fluctuates frequently only by relying on shunt capacitors. Therefore, a coordinated optimization planning method based on soft open point (SOP) and shunt capacitors is proposed. Firstly, the bidirectional generative adversarial network (BIGAN) is used to characterize the uncertainty of wind power output and generate typical scenarios of wind power output. Secondly, a multi-objective optimization planning model of SOP and shunt capacitors is proposed based on the scene analysis method; Then, a solution strategy based on the improved elitist non-dominated sorting genetic algorithm (NSGA-II) is proposed. Finally, the proposed planning model and solution are verified and analyzed in the improved IEEE 33-bus system.

Device series connection is a method to achieve higher blocking voltage with multiple devices. However, a voltage unbalance among the series connected devices is a critical issue that may lead to a failure of the devices. The unbalance can be caused by difference of device characteristics and mismatch of gate signals due to delay of external gate drive circuit. In this work, a voltage balancing control (VBC) for series connected SiC MOSFET submodules is studied to solve the unbalance issue. One submodule consists of two switches and one shunt capacitor. By charging or discharging the shunt capacitor, voltage balancing can be achieved. The VBC is experimentally verified with four series connected SiC MOSFET submodules up to 3 kV DC voltage. Voltage balancing is achieved within 5 % of an expected balanced voltage.

This paper proposes a novel control system for the shunt capacitor equipped with a series inverter with high compatibility with conventional shunt capacitors. The proposed system damps the harmonic resonance of the distribution grid, as its current is controlled to match the one of the conventional shunt capacitor with series reactor, which is expected not to resonate. However, when the grid harmonic content is too high, the control system changes the behavior of the shunt capacitor, making it possible to avoid its overcurrent. Simulation results verify the high compatibility of the proposed system, by analyzing the behavior of the system when it is connected in parallel with the conventional circuits, and experimental results using a downsized model show that it is possible to change the behavior of the system in order to prevent its overcurrent.

Recently, the voltage stability and control of distribution networks become challenges due to the large line impedance, load variations and particularly the presence of distributed generation. This paper presents a coordinated voltage control scheme of distribution systems with distributed generation based on on-load tap changer and shunt capacitors. The problem is to determine the optimal operation of voltage regulation devices to minimize a multi-objective function including power losses, voltage deviations and operation stresses while subject to the allowable voltage ranges, line capacity and switching stresses, etc. The problem is formulated and solved by a modified particle swarm optimization algorithm to treat the large-scale and high nonlinearity property. The proposed scheme is applied to a typical 48-bus distribution network in Vietnam. The result of simulation shows that the voltage profile can be improved while the power loss of distribution systems can be reduced significantly.

En este artículo se presentan los resultados de la programación de la operación obtenidos al aplicar una función objetivo de optimización de costos de incertidumbre para el despacho de energía en varios periodos. Estos se obtuvieron considerando la distribución de probabilidad e incertidumbre tanto de diversas fuentes de generación de energías renovables (solar y eólica) como la gestión de vehículos eléctricos (VE) en un modelo reducido del sistema de potencia colombiano. El algoritmo de optimización heurístico utilizado fue uno de tipo DEEPSO (combinación de enjambre de partículas y evolución diferencial) en que se tuvo en cuenta factores como costos de penalización por la sub o sobreestimación del potencial energético; penalizaciones por limitaciones físicas del sistema como tensiones máximas de los nodos y corrientes máximas de las líneas; optimización del flujo de potencia mediante la inyección de reactivos con capacitores tipo shunt y la utilización de taps de transformadores.

In this study, a methodology for determining the solar and wind DG (distributed generation) capacity is proposed by using sequential optimisation method considering a seasonal variation of load demand, seasonal solar, and wind variations. The load demand profile is collected from state load dispatch centre; whereas solar data are collected from Indian Institute of Technology Kharagpur and wind data are collected from a weather station. Along with the DGs, the shunt capacitors are also placed to improve the voltage profile and energy loss reduction with different scenarios. For this purpose, minimisation of a multi-objective function is considered. The proposed methodology is applied to a 69-bus distribution network. The results for different scenarios show the substantial reduction in the annual energy loss and improvement of voltage profile. The result also shows that maximum amount of profit is gained with both renewable DGs and shunt capacitors. The impact of load growth on the distribution network with and without renewable DGs and shunt capacitors are compared. The analysis reveals that with integrating the renewable DGs and shunt capacitors in the system, the distribution network can take load growth for few more years without violating the system constraints.

Power systems are becoming more complex day by day due to stressed situation in a distribution system, augmented growth in population and high demands of electrical power. In India, the dis...

To enhance the UVC irradiation and prolong the life span of UV-lamps, parameter optimization is conducted for electronic ballasts. In this paper, the double capacitor topology is adopted and the effects of different ratios of shunt capacitors are investigated. Experiments are performed under different lamp power levels for each shunt capacitor ratio. The irradiance in each waveband emitted by the UV-lamp is measured using illuminometers and the variation trends are studied based on the excitation characteristics of mercury atoms. The effective lifetime of the UV-lamp is obtained through application tests, and it is verified to be remarkably prolonged when the double capacitor topology is adopted. Analyses and comparisons are discussed and an optimum shunt capacitor ratio is obtained, taking both increasing the UVC irradiation and prolonging the lifetime of the lamp into consideration.

Increasing penetration of Distributed Generation (DG) in recentyears has presented new challenges for planning and optimal operationof integrated distribution systems. In this scenario, harmonic distortionscaused by non-linear DG operation in the distribution networks havefurther added to the complexities of regulating such interconnectedsystems. In this article, a comprehensive analysis of unbalanced radialdistribution systems (RDS) integrated with non-linear DG has been at -tempted. The analytical assessment has been carried out by consideringvarious voltage harmonics in non-linear DG in the presence of shunt ca-pacitors in the radial distribution systems. Results are obtained for TotalHarmonic Distortion (THD) of voltage and current at various buses ofthe RDS, along with harmonic power profile. An economic assessmentof annual energy loss in the presence of non-linear DG has also been at-tempted. The proposed method is tested on two IEEE radial distributionfeeders interconnected with non-linear DG. Results show that the pres-ence of even acceptable level of voltage harmonics in non-linear DG cancause severe harmonic amplification in the entire network, consequentlyleading to increased energy losses for certain harmonic orders.

This paper addresses an incorporation of Distributed Generation (DG) and shunt capacitor in a distribution system simultaneously for minimizing active power loss. For this purpose, the Index Vector Method (IVM) and Power Loss Index (PLI) approach is utilized to determine the suitable position/location of DGs and shunt capacitors. However, the sizes/capacities of these are determined through population based Gbest-guided Artificial Bee Colony (GABC) meta-heuristic optimization algorithm. The various costs such as purchase active power from grid, DG installation, capacitor installation, DG Operation and Maintenance (O&M) are evaluated at two different load scenarios. In addition to that, technical and economical analyses are examined for various combinations of DGs and shunt capacitors. The proposed methodology is successfully demonstrated on 33-bus and 85-bus radial networks and the obtained numerical outcomes validate the suitability, importance and effectiveness to identify locations as well as sizes of DGs and shunt capacitors.

In conventional HVDC systems where the harmonic filters and shunt capacitors are installed at the ac grid side, the converter transformers inevitably suffer the detrimental impacts caused by harmonic penetration. In this paper, combined with an inductive filtering method, a parallel delta-connected filtering-winding scheme for 12-pulse converter transformer units is proposed to reduce the harmonic currents flowing through the transformers and, thus, to attenuate the harmonic effects on them. This paper describes the presented transformer configuration in terms of the wiring scheme of the 12-pulse converter transformer unit and corresponding flowing paths of different harmonic currents with the orders of $3,6n\pm 1\left(\mathrm{n}=1,3,5,\ldots \right)$ , 11 and 13 in the filtering winding circuit. Then, the mechanism of the proposed scheme on harmonic suppression to the converter transformers is explained theoretically. In an attempt to validate the theoretical analysis, simulations based on PSCAD/EMTDC and experiments in a laboratory prototype system are performed to evaluate the harmonic eliminating performance of the proposed scheme.

The 5-GHz quadrature couplers implemented in GaAs and silicon-based integrated passive device (IPD) technologies are presented. Although GaAs technology is superior to silicon-based technology in terms of substrate resistivity and back-side vias, the quadrature coupler using a silicon IPD process achieved better insertion loss due to thick metal traces and comparable substrate resistivity. While the coupler using the GaAs process employed 4- $\mu \text{m}$ -thick metal traces, the coupler using silicon IPD technology employed 10.8- $\mu \text{m}$ -thick traces realized with via connections between a top metal of 5.3- $\mu \text{m}$ thickness and a bottom metal of 5.5- $\mu \text{m}$ thickness. The couplers using the silicon and GaAs IPD process technologies showed 0.15 and 0.27 dB of insertion loss, respectively. Also, the silicon IPD design uses a slightly different topology which splits a coupled inductor into two coupled inductors with shunt capacitors to achieve a broader distributed bandwidth.

Distributed generation (DG) and shunt capacitors are widely adopted for minimizing power loss in distributed networks. But the high cost of DG units puts a limitation on employing higher rating DGs in distribution networks. So, it is desired that less DG size gives maximum loss reduction for achieving the objective of minimum overall cost of the system. The prominent goal of this paper is to curb the total expenditure occurring due to annual energy loss and cost incurred in installing DG units and capacitor banks. An unsullied methodical approach has been presented in this paper to find out optimal position and rating of DG as well as capacitor units so that the overall cost would be minimal. The method is tested on standard IEEE 69 bus distribution system and 130 bus Indian distribution systems. The outcomes of both the test systems are optimistic and found to be promising when compared with the previous ones.

In this paper, a new test circuit is proposed for overvoltage testing of capacitors based on a motor-driven regulating transformer. Motor drives tap selector which is designed to ensure good electrical contact and low wearing. Keeping the test circuit close to resonance requires lower power rating of regulating transformer. Test circuit is capable to generate overvoltage waveforms according to IEC 60871-1 without use of circuit breakers. A software was developed for evaluation of recorded overvoltage waveforms considering amplitude and time limits. The efficiency of test circuit is demonstrated on an actual overvoltage test performed on MV capacitor.

As one of the key technologies to solve the problem of high short-circuit current, the fault current limiter (FCL) has become a research hotspot in China and abroad. The overvoltage and protection measures of the FCL are the key technologies for its application. Therefore, this paper studies the lightning intruding overvoltage and protection measures for a 500 kV FCL based on a high coupled split reactor (HCSR). Firstly, according to the main topology of the system and the 500 kV HCSR-FCL structure, the lightning intruding overvoltage simulation model of the 500 kV station, including the nearby transmission lines, is established on the PSCAD (Power Systems Computer Aided Design) program. Secondly, the lightning overvoltage of the equipment in the station and the components of the HCSR-FCL are simulated and analyzed when the transmission lines nearby are subjected to lightning shielding failure and back flashover. Meanwhile, the influence of the HCSR-FCL on the lightning overvoltage of the equipment in the station are compared and analyzed before and after the HCSR-FCL is installed. The simulation results show that the overvoltage of the equipment in the station and the components of the HCSR-FCL is more serious when the shielding failure occurs in the transmission lines nearby. The HCSR-FCL can reduce the lightning overvoltage of the equipment in the station, but the maximum inter-terminal and inter-arm lightning overvoltage of the HCSR can reach 1064 kV and 790 kV, respectively, under the current limiting state and the current sharing state. Finally, methods of increasing the arresters on the transmission lines side of the HCSR-FCL and shunt capacitor between each module of the HCSR-FCL are proposed to reduce the lightning overvoltage. The lightning impulse withstand voltage of each component of the HCSR is also proposed: The inter-terminal lightning impulse withstand voltage of HCSR is 170 kV. The inter-arm lightning impulse withstand voltage of HCSR is 200 kV. The terminal-to-ground lightning impulse withstand voltage of the HCSR-FCL is 1550 kV.

Frequent and sizeable voltage fluctuations become more pronounced with the increasing penetration of distributed renewable generation, and they considerably challenge distribution grids. Voltage regulation schemes so far have relied on either utility-owned devices (e.g., voltage transformers, and shunt capacitors), or more recently, smart power inverters that come with contemporary distributed generation units (e.g., photovoltaic systems, and wind turbines). Nonetheless, due to the distinct response times of those devices, as well as the discrete on-off commitment of capacitor units, joint control of both types of assets is challenging. In this context, a novel two-timescale voltage regulation scheme is developed here by coupling optimization with reinforcement learning advances. Shunt capacitors are configured on a slow timescale (e.g., daily basis) leveraging a deep reinforcement learning algorithm, while optimal setpoints of the power inverters are computed using a linearized distribution flow model on a fast timescale (e.g., every few seconds or minutes). Numerical experiments using a real-world 47-bus distribution feeder showcase the remarkable performance of the novel scheme.

This paper presents an efficient analytical technique to identify the optimal location and sizing of the distributed generation (DG) and shunt capacitor (SC) into a radial distribution system (RDS). The main objective of allocating DG and SC is to reduce the power losses which leads to improve the overall voltage profile with considering equality and inequality constraints. The DGs and SCs are placed at the bus that gives minimum power loss, while the optimal size is determined using the analytical technique. Moreover, a load variation with 50%, 100%, and 150% respected to the base case is studied to show the efficiency of proposed algorithm. Overall case studies are carried out using IEEE 69-bus RDS and the obtained results are compared with other optimization techniques used in the same manner.

In Sub-Transmission & Distribution system the significance of HT Capacitor Bank is increasing day-by-day for Shunt compensation. In West Bengal the premier power utility had taken an initiative for installation of HT Shunt Capacitor Banks at 11kV bus of 33/11kV substations. The main motto has been to improve the p.f. under Maximum demand conditions and subsequently improvement of voltage profile by reducing the huge network losses. Thus a part of today’s increasing demand can be served, keeping the same Generation & Transmission capacity and consequently, more revenue can be earned. A systematic approach for designing the shunt compensation system along with post commissioning results have been presented herewith as case study basis.

Volt/var control (VVC) is one of the primary functions of the distribution management system aiming at optimum operation of power distribution networks while respecting all of their operational and security constraints. However, the recent huge integration of highly stochastic distributed generation (DG) sources with the grid presents a significant challenge to the traditional VVC schemes, which assume the future to be perfectly known. This paper presents a two-stage chance constrained optimization scheme to handle these nodal power uncertainties and guarantees that the operational and security constraints are respected for almost all realizations of the uncertainty. The chance constrained model is solved by collecting enough randomly chosen samples from the probability spaces of the uncertain parameters so that the class of the problem, a mixed integer second order cone program (MISOCP), is not elevated. The algorithm not only dispatches the optimum schedule for discrete controlling devices like transformers and shunt capacitors but also optimizes the predefined decision rules for reactive power control of DG sources, thus falling in line with the requirement laid down in the revised IEEE 1547 Standard. Numerical simulations on three different test systems show the superiority of the proposed algorithm over the traditional deterministic methods.

Shunt Capacitor Bank (SCB) is usually preferred by power system design engineers for reactive power supports to run entire electrical network. SCB provides more flat distributed voltage profile, improves power factor of the system, reduces upstream current and hence line losses. Many times it can be configured as a “Harmonics Reduction Filter”. Hence there is need to provide protections to this ‘Heart of power system’ for keeping it present whenever you ‘Need it’. The proposed scheme provides unprecedented technic of capacitor switching differently from sequentially & time dependent In/Out of SCB to achieve target Power Factor as close as possible. The proposed system also provides relay based protection scheme for protection of over/under current, over/under voltage, current unbalancing with detecting number of elements failure & involved phase. The outage time management is done by remotely monitoring & controlling facility.

The impact of penetration of distributed generation (DG) on shunt capacitor operation on a radial MV feeder with shunt compensation is assessed in this paper. Impact of capacitor location and DG location on the capacitor output and on feeder voltage profile in a network are both assessed and analyzed. South African utility capacitor placement methods are considered in studies. Two methods of calculating the feeder voltage profile are used in this study, where Method A is an approximate approach and Method B is a precise approach. Furthermore the accuracy of using Method A and Method B to assess the impact of DG on capacitors on an MV feeder is explored in comparison with results obtained from Power System Analysis (PSA) tools like DIgSILENT Powerfactory. The results inform the choice of using of Method A or Method B for the same analysis when PSA tools are not readily available. Studies are completed with DIgSILENT Powerfactory 2017.

Electronic devices usually operate in a variable loading condition and the power transfer efficiency of the accompanying wireless power transfer (WPT) method should be optimizable to a variable load. In this paper, a reconfigurable WPT technique is introduced to maximize power transfer efficiency in a weakly coupled, variable load wireless power transfer application. A series-series two-coil wireless power network with resonators at a frequency of 150 kHz is presented and, under a variable loading condition, a shunt capacitor element is added to compensate for a maximum efficiency state. The series capacitance element of the secondary resonator is tuned to form a resonance at 150 kHz for maximum power transfer. All the capacitive elements for the secondary resonators are equipped with reconfigurability. Regardless of the load resistance, this proposed approach is able to achieve maximum efficiency with constant power delivery and the power present at the load is only dependent on the input voltage at a fixed operating frequency. A comprehensive circuit model, calculation and experiment is presented to show that optimized power transfer efficiency can be met. A 50 W WPT demonstration is established to verify the effectiveness of this proposed approach.

To meet the increased load demand and improve the distribution network performance, it is necessary to use Distributed Generators (DGs) and shunt capacitors (SCs) simultaneously in the distribution network. In this paper, simultaneous allocation of distributed generators and shunt capacitors in the distribution system using flower pollination algorithm (FPA) is presented. The objectives are to reduce power loss and improve the voltage profile of the distribution system. The suitable nodes for DG and capacitor placement are identified by using the loss sensitivity factor (LSF) technique. FPA method determines the optimal size of the DGs and SCs. The method developed is studied on IEEE 33 bus test system and the results are compared with other methods.

This paper presents a novel analytical methodology to determine location for optimal shunt capacitor placement in power systems. The new method modifies modal analysis technique and develops new formulation to compute the Reactive Contribution Index (RCI) of each load buses based on the inversed reduced Jacobian matrix. The objective of this study is to achieve the most stable condition as well as to minimize network losses. The proposed method is implemented at the modified IEEE 30-bus Reliability Test System (RTS). The simulation results show the proposed method can provide a solution to the ideal shunt capacitor placement to improve the system's voltage stability.

This paper presents a new optimization algorithm, named intersect mutation differential evolution (IMDE) to optimally locate and to determine the size of DGs and capacitors in distribution networks simultaneously. The objective function is taken to minimize the power loss and loss expenses providing that the bus voltage and line current remain in their limits. Simulation results on IEEE 33-bus and 69-bus standard distribution systems show the efficiency and the superior performance of the proposed method when it is compared with other algorithms.

We have designed a low cost embedded device that would reduce the penalty billing of the consumers who fail to maintain the desired power factor.The analysis is made keeping in mind the concern for those bulk consumers of electricity (i.e. 11kV and downwards) in rural and sub-urban areas of India dealing varying load patterns.Switching of shunt capacitor banks though economical but often fail to give satisfactory compensation for varying load patterns. Hence combination of shunt capacitor banks intelligently would give a better solution to this problem. The present work focuses on the formulation of an optimization algorithm based on Ant Colony Search (ACS) technique operational from a Blackfin DSP microcontroller platform. This intelligent algorithm enables switching of appropriate Shunt Capacitor Banks (SCBs) in installations of bulk consumers of electricity to improve their power factor. The application is mainly targeted on cold storages, rolling mills, traction substation and steel plants in India, where SCBs are installed over a long period in an unplanned manner. Unawareness of the impact of energy savings coupled with the fiscal incapability of these users make them unable to install costly power electronic devices for p.f. control ACS based embedded controller is sensitive to unpredictable load changes and selective capacitors switching cause optimal VAR control with minimum stress to the system. Employing the distributed computational model based on ACS becomes an ideal tool for the combinatorial optimization problem to select a best combination within a bank of varying sizes and varying status signifying dynamically changing search space. This low cost device will reduce the penalty billing of consumers by improving the p.f. and improved metered reading. The use of this device will lead to permeation of technology to the strata which needs it most making energy management possible without any human intervention.

This paper attempts to minimize power losses in radial distribution networks and facilitates an enhancement in bus voltage profile by determining optimal locations, optimally sized distributed generators and shunt capacitors by hybrid Harmony Search Algorithm approach. To overcome the drawback of premature and slow convergence of Harmony Search Algorithm (HSA) over multi model fitness landscape, the Particle Artificial Bee Colony algorithm (PABC) is utilized to enhance the harmony memory vector. In the first approach, the formulation echoes the determination of loss sensitivity factor to decide the sensitive nodes and thereafter decides on the optimal rating through the use of hybrid Algorithm. The second approach encircles the role of hybrid Algorithm to search for both the optimal candidate nodes and sizing of compensating devices by significant increase in loss reduction with the former approach. The procedure travels to examine the robustness of the proposed hybrid approach on 33 and 119 node test systems and the result outcomes are compared with the other techniques existing in the literature. The simulation results reveal the efficiency of the proposed hybrid algorithm in obtaining optimal solution for simultaneous placement of distributed generators and shunt capacitors in distribution networks.

This study demonstrates a capacitive reactive loading method for forward-wave couplers based on coupled lines. With the method, a miniaturised forward-wave coupler can be designed by loading either a symmetric or an asymmetric coupled line with shunt capacitors symmetrically or asymmetrically. The method is a generalised version of all previous shunt capacitive loading methods for miniaturisation of forward-wave coupled-line couplers since it provides complete control of not only the maximum coupling level, but also the impedances of the two strips. For the first time, a forward-wave coupled-line coupler is demonstrated that provides an arbitrary maximum coupling level based on 50-Ω lines. Therefore, lengthy and/or complicated impedance matching networks can be eliminated, a more effective miniaturisation is enabled, and performance degradation associated with the additional circuitry is minimised. Experimental results of various forward-wave couplers based on quasi-symmetric and asymmetric coupled lines with various coupling levels and strip impedances are provided to demonstrate the versatility of the proposed method.

This paper investigates the impact of distributed generation (DG) on the output of shunt capacitors using power system analysis (PSA) tool DIgSILENT Powerfactory. The study then investigates two non-PSA techniques and one alternative PSA technique which makes use of Load Flow Sensitivities (LFS) to perform voltage assessment and assess the effect of DG on medium voltage (MV) shunt capacitors. The use of non-PSA techniques is crucial to utilities in developing countries like those found in sub-Saharan Africa. Globally the use of PSA tools are part of standard practice and the use of LFS can be shown to reduce the steps involved in voltage analysis and provides additional benefit to using PSA tools. In this paper, authors use South African MV capacitor placement methodologies implemented by the national energy utility, Eskom.

In a classical UHVDC system, the switchable units (including AC filter and shunt capacitor banks) and associated equipment (e.g. switchgear etc.) occupy around 1/3 of the total converter station footprint. This is a costly part of the converter station. To reduce the cost of the converter station, one way could be increasing the size of each single switchable unit, hence reducing the total number of the switchable units. The number of associated equipment will be also reduced accordingly. Therefore, the footprint and the cost of a converter station could be reduced. In this paper, an optimal size design is proposed, which could maximize the size of a single switchable unit. Maximization can be done by using an optimal HVDC control method, or by using an optimal control method coordinated with a STATCOM installed at the converter station. The optimal design schemes for switchable units are compared with a conventional design and the results are presented in this paper.

A novel methodology based on the recent metaheuristic optimization algorithm Salp Swarm Algorithm (SSA) for locating and optimal sizing of renewable distributed generators (RDGs) and shunt capacitor banks (SCBs) on radial distribution networks (RDNs) is proposed. A multi-objective function index (MOFI) approach is used for assuring the power quality (PQ) through enhancing the voltage level in addition to minimizing the power losses of the system and the whole operating cost of the grid. The proposed methodology is tested via 33-Bus standard radial distribution networks at different scenarios to prove their validity and performance. The obtained results are compared with the Grasshopper Optimization Algorithm (GOA), and the hybrid Particle Swarm Optimization (PSO) and Gravitational Search Algorithm (PSOGSA). The SSA optimizer proved its superiority with high attitude and accuracy for solving the problems of RDGs’ and SCBs’ locations and capacities simultaneously. An Egyptian practical case study at different load levels via different scenarios including the control operation within 24 h is considered.