Capacitor Bank Research Articles

Positioning and Sizing of PV-Based DG and Capacitor in Realistic Distribution Network and Verification through ETAP Simulation

Distributed generation offers a bright future for electric networks, but requires optimal allocation of dispersed resources and an acceptable optimization technique. This article proposes optimal integration of DGs and capacitor banks to optimize distribution network parameters. Imperialist competitive algorithm (ICA) has been used to optimize the distribution network parameters such as optimal location and capacity of Photo Voltaic Distributed Generator ((PVDG) & capacitor. Loss reduction, declination in emission, and an enhanced voltage profile are major advantages of positioning DGs into the distributive topology. The proposed model has been validated and tested on IEEE-33 and Indian real system of 130 bus of Jaipur City for different load patterns. Furthermore, the results obtained from ICA have been verified by simulating the test systems on ETAP software.

Circuit design for doubling the toroidal magnetic field on the QUEST spherical tokamak

Various scenarios of electron cyclotron heating can be explored in a spherical tokamak with a high toroidal field. On the QUEST spherical tokamak, doubling the toroidal field results in the emergence of the fundamental resonance layer for 28 GHz electron cyclotron waves. The second-harmonic resonance layer shifts toward the plasma central area. To increase the coil current from 50 to 100 kA, a current source is designed with 125 modules in parallel. The module power supply comprises a bank of lithium-ion capacitors and a DC–DC buck converter. In the bench test of a single module, the current was found to increase linearly and maintained the flat-top as programmed.

Integration of Photovoltaic Units, Wind Turbine Units, Battery Energy Storage System, and Capacitor Bank in the Distribution System for Minimizing Total Costs Considering Harmonic Distortions

Integration of Photovoltaic Units, Wind Turbine Units, Battery Energy Storage System, and Capacitor Bank in the Distribution System for Minimizing Total Costs Considering Harmonic Distortions

Effective Power Loss Management in the Distribution System by the Hybrid Cuckoo Search Grey Wolf Optimizer

One of the most convoluted parts of an electrical power system is its distribution system. Compared to generation and transmission losses, distribution losses are very high in the vertically integrated power system. A modern smart grid involves bidirectional power flow due to Renewable Distributed Generations (RDGs). Integration of RDGs near the load points results in a reduction in the distribution losses. This paper proposes the new Hybrid Cuckoo Search Grey Wolf Optimizer (HCSGWO) to optimally place the RDGs such as Solar Photo Voltaic and Fuel Cells and Capacitor Banks (CBs) for the improvement of voltage profiles in each bus and minimization of losses. The hybrid algorithm utilizes the advantages of both the Cuckoo Search and Grey Wolf algorithm. The proposed approach is tested with the Standard IEEE 33-bus system and the real-time TN 84-bus distribution system at all load models such as constant current, constant power, and constant impedance. The HCSGWO minimizes the system losses by optimally placing both the RDGs and CBs when compared to other algorithms. Losses are reduced by installing CBs in the real-time system and significant improvement is achieved in the voltage levels of each bus in the system.

Research on Optimal Voltage Control of Distribution Network with the Participation of EVs and PVs

With the accelerating penetration of photovoltaics (PVs) and electric vehicles (EVs), distribution networks face the risks of voltage violations and fluctuations. On the one hand, conventional voltage regulation resources like OLTC transformers and capacitor banks feature slow response and limited lifetime duration, making them incapable of quickly responding to the temporary voltage issues created by PVs and EVs. On the other hand, EVs and PVs interact with the power grid via fully controllable power electronic converters capable of real-time adjusting their operating settings, making them ideal voltage support resources. To exploit the voltage support capability of PVs and EVs, this paper proposes a two-stage control scheme for the voltage regulation of distribution networks, consisting of the day-ahead and intraday control stages. The day-ahead control mitigates potential voltage violations via day-ahead scheduling of the operation settings for OLTC transformers and capacitor banks. The intraday control further alleviates voltage deviations and voltage fluctuations based on the reactive power support of PV systems and the rational EV charging/discharging scheduling. A rolling optimization-based control technique is proposed in the intraday control stage to achieve real-time control of EVs and PVs with the stochastic nature of EV charging behaviors inherently considered. The proposed two-stage voltage regulation scheme is validated via case studies performed on the IEEE 123-node test feeder integrated with PVs and EVs.

Data-Driven Combined Central and Distributed Volt/Var Control in Active Distribution Networks

This paper proposes a two-stage combined central and distributed Volt/Var control (VVC) strategy to coordinate both utility-scale and customer-owned photovoltaics (PVs) for voltage regulation in active distribution networks (ADN). In the first stage, with day-ahead PV and load predictions, the central controller (CC) performs optimal power flow (OPF) to determine the hourly dispatch of on-load tap changers (OLTC) and capacitor banks (CBs). In the second stage, the ADN is partitioned into different zones only based on PV and load types. The zone controllers (ZC), which is formulated by deep neural networks (DNN), then communicate with their neighbors and track the optimal total reactive power support of PVs in each zone. In the offline training process, an analytical derivation to minimize power losses is also provided that can help the input and output selection of DNN. To online dispatch reactive power for individual utility-scale and customer-owned PVs in corresponding zones, a multi-mode reactive power allocation strategy is proposed. Three different modes namely loss reduction mode (LRM), fair power sharing mode (FPM) and voltage security mode (VSM) are designed to meet varying operation requirements, which can mitigate voltage violations with fair participation for customers and reduced power losses for system operators. Numerical simulations are performed on the IEEE 33-bus distribution system to demonstrate the effectiveness of the proposed method in finding a trade-off between voltage security and loss minimization with fairness.

Improvement of Power Quality in Primary Distribution Systems Based on Static-Var Compensators

A flexible AC Transmission Systems (FACTS) is a new technology offers a fast and reliable control over the transmission and distribution parameters like voltage and phase angle between the sending end voltage and receiving end voltage. Distribution static synchronous compensator (DSTATCOM) is a second generation member of the (FACTS) controllers. Reactive power compensation is an important aspect in the control of distribution systems. Reactive current in addition to increasing the distribution system losses, introduces voltage drop at lead point and finally it causes poor power quality in power systems. Primary radial distribution feeders have high resistance to reactance ratio, which causes voltage drop and high power loss in radial distribution systems. providing high demanding power to entire load while maintaining voltage magnitude at acceptable range is one of the major system constraints, using of capacitor banks to improve the reactive power have not quite enough at high reactive power feeder, because it have more slow in step by step response and have not capable to generate continuously variable reactive power. In some primary distribution feeders at the state of Khartoum, it is observed that there are some appropriate drops in voltage and quality service at high reactive power loads although some individual capacitor banks have been connected at these feeders, from here we researched for a new technology to overcome this problem. A steady-state model of (DSTATCOM) is proposed and developed to compensate the reactive power by using a Voltage Source Converter (VSC) with Pulse Width Modulation (PWM) and cascade control of four direct proportional integral controllers (PI) in synchronous reference frame. The detailed modeling and control design of (DSTATCOM) with specific typical radial primary distribution feeders (industrial, commercial, residential) are presented and implemented along necessary mathematical model equations in the Matlab software. Simulation schemes of (DSTATCOM) are done with help of control block diagrams and stability analysis. Load flow is an important method for analysis, operation and planning studies of any power system in a steady-state condition. In this research backward forward sweeps load flow method (Kirchhoff’s Laws) has been proposed rather than Newton-Raphson and Fast decoupled methods because the distribution feeders have a high R/X ratio which make the systems are ill-conditioned iterations analysis. (DSTATCOM) was installed on specific typical radial feeders at the (DSTATCOM) which using for distribution lines and load compensation has been the subject of considerable interest beside it is a new technology for a good power quality solution. Keywords: Power System, Flexible AC Transmission Systems (FACTS) Devices, STATCOM, PI Controller DOI: 10.7176/ISDE/13-1-05 Publication date: May 31 st 2023

Coordinated Use of Smart Inverters With Legacy Voltage Regulating Devices in Distribution Systems With High Distributed PV Penetration—Increase CVR Energy Savings

This paper studies the coordinated use of smart inverters with legacy voltage regulating devices to help increase the energy savings from conservation voltage reduction (CVR) in distribution systems with high photovoltaic penetration. Two voltage optimization algorithms are developed to evaluate the CVR benefit by considering two types of smart inverter functions: aggregated reactive power control and autonomous volt/VAR control. In each algorithm, smart inverters are coordinately controlled with the operation of legacy voltage regulating devices including load tap changers and capacitor banks. Both algorithms are tested on representative utility distribution system models. Simulation results demonstrate that the proposed algorithms can achieve around 1.8-3.6% energy savings when only using legacy voltage regulating devices and an additional 0.3-0.9% when adding smart inverters.

Effect of die conductivity on electromagnetic forming of tube

Electromagnetic forming (EMF) is a high-speed forming technology that uses electromagnetic forces to deform materials. In this process, the capacitor bank stores energy and it is discharged through the coil; here small part of stored energy is utilized, and the remaining part is wasted through losses. The current loss is significant. It can be in the form of loss in coil, die, fixtures, etc. It has been observed that the range of efficiency of the EMF process varies between 10 and 40%. Therefore, the present work explores into reducing the losses by using a suitable die material to improve the efficiency of the EMF process. Here, the effect of die material on the deformation of Al tube is studied. For this study, two die of same geometry and different materials, namely nylon and steel, are used. It is observed that the effect of die material plays important role in the EMF process. Almost 5% increase in deformation is observed with nylon die compared to steel die at the same discharge energy. The FE based simulations are carried out and results are validated experimentally with 94% agreement.

An Empirical Performance Assessment of Infrared Thermography for Real-time Monitoring of Electrical Systems in the Coco Fibre Industry

The quality of the electrical network, which includes MV panels, DBs, MCBs, sub-circuits with fuse units, and electrical motors for machine tools, determines production in any sector. Most drive systems employ inductionmotors. System temperature indicates health. Excess temperature is rarely detected due to breakdown. This case study presents real-time data for a leading coir industry from each electrical circuit and motor in several machine tools. Every section is thermographed and compared to the allowed temperature range. Thermographic analysis is non-contact and uses fewer meters and instruments. A harmonic analyzer measures THD using data from the full testing period. Modern energy audits save 10–15% on energy. Suggestions include modest restructuring of electrical network load distribution, little investment in capacitor banks in each section of induction motors, and thorough analysis and corrective measures based on customer needs.

Online Adaptive Parameter Estimation of a Finite Control Set Model Predictive Controlled Hybrid Active Power Filter

This paper presents a novel strategy for online parameter estimation in a hybrid active power filter (HAPF). This HAPF makes use of existing capacitor banks which it combines with an active power filter (APF) in order to dynamically compensate reactive power. The equipment is controlled with finite control set model predictive control (FCS-MPC) due to its already well-known fast dynamic response. The HAPF model is similar to a grid-connected LCL-filtered converter, so the direct control of the HAPF current can cause resonances and instabilities. To solve this, indirect control, using the capacitor voltage and the inverter-side current, is applied in the cost function, which creates high dependency between the system parameters and the equipment capability to compensate the load reactive power. This dependency is evaluated by simulations, in which the capacitor bank reactance is shown to be the most sensitive parameter, and, thus, responsible for inaccuracies in the FCS-MPC references. In order to minimize this problem without increasing the complexity of the FCS-MPC algorithm, an estimation technique, based on adaptive notch filters, is proposed. The proposed algorithm is tested in a laboratory prototype to demonstrate its ability to follow variations in the HAPF capacitor reactance, effectively correcting the reactive power reference and providing dynamic reactive power compensation. During the tests, the proposed algorithm was capable of keeping the supplied reactive power within a 1% error, even in a situation with 33% variation in the HAPF capacitor reactance.

Two-stage voltage regulation in power distribution system using graph convolutional network-based deep reinforcement learning in real time

The model-based voltage control is widely used to mitigate quick voltage fluctuations caused by renewable energy uncertainties. However, the accurate and complete parameters of the distribution system are rarely available in practice. A two-stage voltage regulation framework based on a mixed-integer second order cone optimization programming (MISOCP) model and graph convolutional network-based deep reinforcement learning (GCN-DRL) is proposed for active distribution system voltage regulation. Specifically, in the day-ahead stage, a MISOCP is proposed for hourly voltage regulation optimization with capacitor banks (CBs), on-load tap changers (OLTC), and energy storage systems (ESS). Then, a GCN-DRL method is proposed in the real-time stage for dispatching reactive power from the intelligent inverters connected to the photovoltaic systems to alleviate the voltage fluctuations. The proposed grid topological graph convolutional network (GTGCN) leverages the distribution system’s graph structure information and the convolutional operation to capture and embed the graphical features among nodal measurements. Then, the deep deterministic policy gradient (DDPG) is innovatively proposed for GCN-DRL to learn the high-efficiency voltage regulation policies, which can be implemented in a real-time manner in practice. The proposed voltage regulation model is investigated on a modified IEEE 33-node distribution system and a 25-node unbalanced distribution system. The numerical results illustrate the high effectiveness and efficiency of the proposed adaptive robust operating model.

Distributed data-driven distributionally robust Volt/Var control for distribution network via an accelerated alternating optimization procedure

This paper proposes a distributed data-driven distributionally robust volt/var control (DDDR-VVC) approach which schedules on-load-tap changer (OLTC), capacitor banks (CBs) and Photovoltaic (PV) inverters coordinately. With integration of distributed optimization and data-driven distributionally robust optimization, the DDDR-VVC model is constructed to reduce power losses and maintain voltage within allowable range under uncertainty. To fully address the uncertainty impacts, construction of uncertain set is improved through that the probability distribution sets and trapezoidal fuzzy functions are developed to model PV supply and load demand respectively. An accelerated alternating optimization procedure which integrates the alternating direction method of multipliers and the column-and-constraint generation algorithm is proposed. This method improves the dual information update via Nesterov’s accelerated gradient method, thus solving the DDDR-VVC model at a high convergence rate. The effectiveness of proposed method is verified through numerical simulations using IEEE 123 bus test system.

Implementation of IoT-based energy monitoring and automatic power factor correction system

Energy monitoring facilitates quick access and helps to know the power utilization and normal and abnormal conditions. Nowadays, many applications and majorly industries face problems regarding power quality. In the power system, the power factor plays a vital role in power quality. The addition of capacitance overcomes the decay of the power factor and reduces the power loss. This paper aims to build an automatic power factor correction (APFC) system, which can monitor the energy consumption of a system and automatically improve its power factor. In the design, an open-source energy monitoring library has been implemented for accurate power calculations. This paper carried out the work of hardware experimentation of energy monitoring and automatic power factor correction using a capacitor bank with the association of Internet of Things (IoT) technology. Build a mobile application to more simply and comfortablely monitor power and correct automatically. The developed hardware model’s performance is validated with and without load conditions. The result proves that the designed Raspberry Pi-based energy monitoring and automatic power factor correction system outperforms to improve the power factor without human interaction by properly switching the capacitor bank. Hence, the power loss, penalty, and power quality-related problems were resolved based on the proposed approach. The proposed design is compact, simple, and easy to implement and aids in power system advancement.

Online Power Transfer Regulation Between Transmission and Active Distribution Systems for High-Voltage Support

Regulation of power transfer between High-voltage Side (HVS) and Distribution Power Systems (DPS) is an urgent issue for modern power grids. During light loading, active DPS can export the extra power to the transmission system and may create voltage rise at HVS. In other words, active DPS are highly required to provide ancillary services to HVS during its unexpected failures. Therefore, this study suggests an online centralized control approach to satisfy the international Demand Connection Codes (DCC) at Transmission/Distribution interconnection point or fulfill the power requests from HVS. A linear power-flow taking into account the voltage-dependence characteristics of electric loads is used for problem formulation. The problem is formulated as a mixed integer quadratic optimization problem (MIQP). The MIQP problem can easily be solved to its optimality solution while reducing the complex computations. The proposed method can regulate both active and reactive power transfer at the interconnection point and thus it can be operated at different modes. The proposed control method uses the Distributed Generation (DGs), Capacitor Banks (CBs), and controllable loads as control variables. The use of controllable loads can increase the responsibility level of DPS in satisfying the DCC requirements. The suggested approach was checked on a 11 kV 77-bus active DPS.

Perbaikan Tegangan dengan Menggunakan Kapasitor Bank 25 MVAR pada Gardu Induk Banda Aceh

The Nagan Raya coal-fired power plant in Aceh, Indonesia, serves as a major supplier of electricity to the region's power grid. However, the power generation unit of the plant, which supplies reactive power to the subsystem, often experiences disturbances that cause voltage values in the Banda Aceh substation system to decrease. This decrease in voltage can be detrimental to the quality of power supplied to the consumers. To address this issue, a capacitor bank with a capacity of 25 Mvar was installed at the end of 2016. The capacitor bank was successful in increasing the voltage value at the substation and proved to be an effective solution. However, with the anticipated growth in load in the coming years and the possibility of future disturbances in the power generation unit, it has been proposed that an additional capacitor bank unit with the same capacity be installed to further enhance the voltage quality at the Banda Aceh substation. To assess the feasibility of this proposal, simulations were carried out using ETAP 12.6.0 software. The simulation results show that the addition of a 25 Mvar capacitor bank unit would lead to an increase in the substation voltage value of around 5-6 KV. This increase in voltage would help to maintain the quality of power supplied to the consumers and ensure that the power grid remains stable even in the event of disturbances in the power generation unit. Overall, the proposed installation of an additional capacitor bank unit would be a cost-effective solution to enhance the voltage quality at the Banda Aceh substation and ensure the stability of the power grid. This solution could be adopted by other power plants facing similar issues in maintaining voltage quality in their power grid systems.

Optimalisasi Performa Sistem Tegangan dengan Pemasangan Kapasitor Bank pada Pembangkit Listrik Tenaga Uap (PLTU) Nagan Raya

This research aims to optimize the performance of the voltage system at the Nagan Raya Steam Power Plant (PLTU) by installing capacitor banks. Capacitor banks are integrated into the system to increase voltage stability, reduce power losses, and increase energy efficiency in PLTUs. The research method involves analyzing the existing voltage system, designing the capacitor bank installation, and evaluating the system performance after installation. It is hoped that the results of this research can make a positive contribution in improving the performance of PLTU Nagan Raya and overall energy efficiency.

УМОВИ ПЕРЕЗАРЯДУ КОНДЕНСАТОРІВ КОМУТУЮЧОЇ ЛАНКИ ТРИФАЗНОГО МОСТОВОГО КОМПЕНСАЦІЙНОГО ПЕРЕТВОРЮВАЧА

The development of the authors is aimed at creating a modern power electronics device with high energy characteristics. In the scheme of a three-phase bridge compensation converter, the role of the commutator is a performed by a three-phase group of fully controlled devices. This technical solution allows for controlled recharging of the commutating link capacitors. In this case, the ultimate goal is to create such conditions for the formation of a commutating voltage, which, in shape and magnitude, is capable of providing a compensation mode of operation of power electric diodes. The conditions for recharging the capacitors of the commutating link were studied in three modes: the adjustment is carried out within the limits of the operation of the diodes of its phase, the next and the previous one. The conditions under which a three-phase bridge converter is able to operate effectively in a compensation mode are proved. To do this, when recharging the capacitor bank, a group of fully controlled devices of the commutated link must be regulated within the operation of the power electric diode of its own or subsequent phase. Comparison of the characteristics of the commutating voltage for different modes of its formation is carried out by the method of harmonic analysis. References 8, figures 5, tables 2.

Efficient Integration of Fixed-Step Capacitor Banks and D-STATCOMs in Radial and Meshed Distribution Networks Considering Daily Operation Curves

The problem regarding the optimal integration of efficient reactive power compensation in radial and meshed distribution networks using fixed-step capacitor banks and distribution static compensators (D-STATCOMs) is addressed in this research paper by proposing a master–slave optimization methodology. Radial and meshed distribution topologies are considered for the grid structure while including variable active and reactive demand curves. An economic analysis is performed, considering the net present value of the optimization plan, as well as the costs of energy losses and the capacitor banks’ acquisition, installation, and operation. In the case of the D-STATCOMs, an annualized costs analysis is presented. In the master stage, the discrete version of the generalized normal distribution optimization (GNDO) algorithm selects the nodes and the sizes of the capacitor banks. In the slave stage, the successive approximations power flow approach is implemented. Numerical results in the IEEE 33-bus grid (with both radial and meshed topologies) and the IEEE 85-bus grid (with a radial configuration) demonstrated the proposed master–slave optimization’s effectiveness in minimizing the project’s expected net present value for a planning period of five years. Moreover, a simulation in the IEEE 69-bus grid under peak operation conditions showed that the GNDO approach is an excellent optimization technique to solve the studied problem when compared to combinatorial and exact optimization methods. In addition, numerical validations considering D-STATCOMs in the IEEE 85-bus grid confirmed the effectiveness and robustness of the GNDO approach in addressing problems associated with optimal reactive power compensation in medium-voltage distribution systems.

Dynamic Performance of a Hybrid Synchronous Machine with Ultra-High XD/XQ Ratio

This paper presents a hybrid synchronous machine with ultra-high XD/XQ ratio. A conventional synchronous machine has two components of output power; the excitation and the reluctance component. The reluctance power which depends on the saliency ratio (XD/XQ ) is negligible when compared with the excitation component. A hybrid machine with variable XD/XQ ratio has the capability of raising the reluctance component of the power to infinity theoretically. The stator frame of the hybrid machine is stacked with two identical cylindrical cores (A, B) that are magnetically isolated. A hybridised rotor; salient cum cylindrical is used. There are two windings on the stator core stacks identifiable as the main and control windings respectively which are electrically isolated but magnetically coupled. The main windings are connected in series across the two stacks (A and B) and the terminals connected to the utility supply for motor operation while for generator, the terminals feed the load busbar. The control windings are transposed in passing from one stack to the other and terminated across a balanced adjustable capacitor bank. It is shown that the quadrature axis reactance (XQ) of the hybrid machine can be adjusted from zero to infinity (0<=XQ<=inf.) theoretically by varying the balanced adjustable capacitor bank. The reluctance component of the output power of the machine which depends on the reactance ratio (XD/XQ ) is also seen to theoretically increase to infinity. The reluctance power is shown to be twice the excitation power when the capacitor of 800uf is connected to the control winding. Depending on the value of the capacitive reactance, the reluctance power can be made even ten times the excitation power.