Voltage Sag Compensation Research Articles

Sliding mode control based dynamic voltage restorer for voltage sag compensation

The reliability and efficiency of electrical power systems are critical for modern industries, which increasingly rely on electric machines and devices. However, power electronic converters add non-linear demands to the electric power distribution systems (EPDS), that can cause power quality (PQ) problems, which could harm electric devices. As a result, EPDS are pointed for the most effective and economical techniques to enhance PQ. Therefore, Dynamic Voltage Restorer (DVR) is employed to maintain voltage stability in modern EPDS. This study focuses on the application of Sliding Mode Control (SMC) in DVRs to protect against voltage dips, enhancing power system sustainability. It details the construction, operation, and control methods of DVRs, comparing the conventional PI-controller with SMC. The arctic puffin optimizer is utilized to get the optimum gains of the PI regulator, and at the same time, it is used to specify the optimal sliding surface required for SMC. A distribution system contains DVR is suggested and implemented utilizing Simulink/MATLAB. The simulation results of the DVR employing SMC and the conventional PI-controller demonstrate a marked improvement in voltage regulation and power quality. Specifically, the SMC-based DVR exhibited a reduction in voltage sag duration and magnitude by approximately 30 % compared to the PI-controller. Additionally, the total harmonic distortion (THD) in the load voltage was reduced by 25 %, indicating a significant enhancement in power quality. These improvements of the enhanced performance of the SMC-based DVR supports the seamless integration of renewable energy sources, which often introduce variability into the power grid.

FRT capability improvement of a wind power system using support vector regression and deep neural network models

ABSTRACT The increasing energy demand and environmental conditions have led many countries to favor renewable energy,such as wind and solar,over conventional power plants. As per the Central Electricity Authority (CEA), India’s wind power capacity has grown substantially, reaching 45,154 MW in 2023, from 22,465 MW in 2013. However, integrating wind generators to an existing power system network can reduce transient stability during faults. To prevent wind turbine disconnection during faults, Indian grid code authorities mandate Fault Ride Through (FRT) or Low Voltage Ride Through (LVRT) capability for wind turbines. This paper proposes Dynamic Voltage Restorer (DVR) for enhancing the FRT capability of a constant speed wind turbine. Analysis and simulation are done on a fixed speed wind turbine employing Squirrel Cage Induction Generator (SCIG) under balanced and unbalanced voltage sags. Performance of DVR with two Artificial Intelligence-based controllers, Support Vector Machines(SVM) Regression Model Based Supervised Machine Learning algorithm, and Deep Neural Network (DNN) controller, is analysed and compared. The SVM Regression algorithm, achieves 100% voltage sag compensation under unbalanced voltage sags, reduces torque pulsations to 25% and maintains rotor speed at rated values, enabling the turbine to remain connected to the grid. Additionally it reduces Total Harmonic Distortion to 2%.

Research on power quality improvement system based on dynamic voltage restorer

AbstractPower quality is a critical issue in power systems that can affect the performance and reliability of sensitive equipment. The dynamic voltage restorer (DVR) is a widely used technology for improving power quality, but it mainly focuses on mitigating voltage sags and often neglects the issue of harmonic distortion. This paper proposes a DVR voltage compensation strategy based on the discrete Fourier transform (DFT). This strategy utilizes the DFT to analyze the voltage waveform, separating the fundamental and desired harmonic components. With this strategy, the DVR can effectively compensate for voltage sag and achieve selective harmonic compensation, thereby improving the power quality of the power system. Additionally, a method utilizing hardware circuitry and an LED as a timestamp is proposed to dynamically estimate digital siginal processor (DSP) resource occupancy rate in real‐time, ensuring effective compensation while minimizing resource occupancy. A 3 kW DVR experimental prototype was constructed and tested to evaluate the practicality of the proposed strategy. The simulation and experimental results show that the method proposed in this paper successfully realizes the compensation of voltage sag and harmonics in the power system, and improves the stability and reliability of the power system.

Ultracapacitor Based Voltage Sag Compensation in Armored Vehicles

The article describes the voltage sag compensation of a DC bus and improved regulation of battery voltage while starting a diesel engine starter motor using continuously acting ultracapacitor modules with an equivalent series resistance energy sharing principle in an armored fighting vehicle. in general, the starter motor draws large power during starting, thereby demanding a large inrush current that is fed by the battery power system. This causes a large fall in the terminal voltage of the battery. This paper proposes a 24 V, 800 Ah Li-Acid Storage Device Bank with a 300 F, 30 Volt Ultracapacitor Module that energizes an 11-Kilowatt starter motor, which initiates the rotation of a diesel engine shaft. The time-based structures of lead-acid power sources, ultracapacitors, and starter motors will be analyzed and simulated based on the experimental results. The complete circuit was verified by MATLAB/SIMULINK Software, where voltage sag is reduced while starting a starter motor from 19.1 V to 22.3 V and 75.11% of energy is shared by the ultracapacitor. The same configuration with a reduced ultracapacitor rating of 63 F and 30 V has been implemented in hardware, and the voltage sag is limited from 18.9 V to 21.1 V with 27% of the energy shared by the ultracapacitor. Both simulation and hardware results are implemented and verified.

Combined operation of UPQC and fuel cell with common DC bus

In this paper analysis results of a cooperation of the unified power quality conditioner with the fuel cell units are presented. A comprehensive control strategy is introduced to extract the compensating signals for the control of the proposed system. The used control strategy can extract the reference currents and voltages of UPQC fast and accurately in the presence of harmonics and/or frequency oscillation. The proposed scheme can compensate voltage sag, voltage interruption and harmonics at the Point of Common Coupling (PCC) on power distribution system. The simulation results prove the efficiency of using the presented method on power quality improvement

Voltage Sag, Swell, and Interruption Compensation Using DVR Based on Energy Storage Device

Voltage Sag, Swell, and Interruption Compensation Using DVR Based on Energy Storage Device

Intelligent Voltage Sag Compensation Using an Artificial Neural Network (ANN)-Based Dynamic Voltage Restorer in MATLAB Simulink

An innovative Dynamic Voltage Restorer (DVR) system based on Artificial Neural Network (ANN) technology, implemented in MATLAB Simulink, accurately detects, and dynamically restores voltage sags, significantly improving power quality and ensuring a reliable supply to critical loads, contributing to the advancement of power quality enhancement techniques. Voltage sags are a prevalent power quality concern that can have a significant impact on sensitive electrical equipment. An innovative approach to address voltage sags through the operation of a Dynamic Voltage Restorer (DVR) based on Artificial Neural Network (ANN) technology. The proposed system, developed using MATLAB Simulink, leverages the ANN's capabilities to accurately detect voltage sags and dynamically restore the voltage to the affected load. The ANN is trained using a comprehensive dataset comprising voltage sag events, enabling it to learn the intricate relationships between sag characteristics and optimal compensation techniques. By integrating the trained ANN into the DVR control scheme, real-time compensation for voltage sags is achieved. The effectiveness of the proposed system is rigorously evaluated through extensive simulations and performance analysis. The results demonstrate the superior performance of the ANN-based DVR in terms of voltage sag detection accuracy and restoration precision. Consequently, the proposed system presents an intelligent and adaptive solution for voltage sag compensation, ensuring a reliable and high-quality power supply to critical loads. This research contributes to the advancement of power quality enhancement techniques, facilitating the implementation of intelligent power system.

Voltage Sag Detection and Compensation Signal Extraction for Power Quality Mitigation Devices

The importance of voltage quality is continuously increasing in electrical networks due to the rising manufacturing costs resulting from system faults and disturbances in utility dynamics. Researchers generally prefer reference-frame transformation-based methods to detect and mitigate these disturbances. However, these methods are adversely affected during unbalanced loading and disturbances due to their direct dependence on system dynamics (currents and voltages). In this study, a new and simple method based on Clarke transformation is proposed to detect disturbances and generate compensation signals for Power Quality Mitigation Devices. The aim is to address the deficiencies of existing approaches. Firstly, the Clarke transformation is introduced through the vector presentation. Then, the mathematical derivation of the proposed method is provided to enhance readers’ understanding. The voltage sag detection and compensation signal extraction of its control algorithm for a Dynamic Voltage Restorer is illustrated graphically. Subsequently, a simple power system is created using a simulation program. Balanced and unbalanced voltage disturbances are applied to the test system to demonstrate the validation of the proposed method under distorted system conditions. The results of voltage sag detection and compensation signal extraction for both the proposed and existing methods are compared at the end of the case studies.

Research on Voltage Sag Detection Algorithm based on Regional Transmission System

Voltage sag is the most common power quality issue and often brings huge economic losses. To achieve voltage sag prevention and compensation, it is necessary to effectively detect voltage sag characteristics. An IEEE-39 node system model is built using Simulink, combined with common aer transformation methods and αβ. The transformation method accurately detects voltage sag accidents and incorporates a derivative algorithm, greatly reducing the detection delay and meeting the real-time and accuracy requirements of actual systems.

A single-phase direct buck-boost AC–AC converter with minimum number of components

In this paper, a single-phase direct pulse width modulation (PWM) buck-boost AC–AC converter is proposed. The proposed converter utilizes a minimum number of semiconductor switches and passive components that decreases the converter power losses and offers high efficiency. It can be operated with simple PWM control and doesn’t require soft-commutation strategies. It does not suffer from input source shoot-through and commutation problems. Moreover, it supplies both continuous input and output currents. The common sharing ground of the input and output gives the proposed converter the feature that it can be utilized for voltage sag and swell compensation. A comparison of the proposed converter performance with similar existing converters is presented. Also, detailed circuit analysis, component design guidelines, and simulation results using the MATLAB/Simulink environment are demonstrated. A laboratory prototype has been built and tested to validate the converter performance and confirm the results obtained by computer simulation.

Location and Capacity Determination for Energy Storage System Involved in Compensating Voltage Sag

For the energy storage system participating in the grid voltage sag compensation service, a location and capacity determination method based on the joint compensation strategy of distributed energy storage systems and dynamic voltage restorer is proposed. Firstly, a two-layer siting and determining capacity model for distributed energy storage systems is established, with the upper layer aiming to minimize the installation cost of distributed energy storage systems and the voltage crossing cost of sensitive loads, and determine the optimal access point for energy storage system. The lower layer determines the optimal configuration capacity of the energy storage system by targeting the compensation cost of the energy storage system, the dynamic voltage restorer, and the voltage satisfaction of sensitive loads. Then, the arithmetic simulation with IEEE33 bus system shows that the proposed method can select a reasonable access point for energy storage system and reduce the configuration capacity.

Multi-stage voltage droop compensation based on resonant circuit for unipolar solid-state Marx Generators.

The low-voltage droop of high-voltage pulses is required to provide stable pulsed electric fields in many applications. Increasing the capacitance of energy storage capacitors increases both the size and the cost of the system. In this paper, four compensation stages based on the resonant circuit have been inserted into a 16-stage solid-state Marx generator to compensate for the voltage droop in different conditions. The nearly linear part of the sinusoidal voltage is precisely added to the load during discharging as compensation, and the rectangular pulsed voltage with little droop can be realized. Different numbers of compensation stages and different resonant inductances can compensate the droop to different levels, which means the compensation effect is also adjustable. Moreover, these compensation stages can operate as common stages in Marx generators as long as we open-circuit the resonant circuits. Since the capacitors in resonant compensation stages are also charged in parallel with capacitors in common stages, no auxiliary power supply is required. Simulating and experimental results show that the droop of a 9kV pulse can be ideally compensated over a 500Ω resistive load at various pulse widths. The pulse width should be shorter than the length of the nearly linear part of the sinusoidal voltage.

A stored energy-based control strategy to improve LVRT capability of HRES using PSO & WCA optimized DVR

The article presented here utilizes the particle swarm optimization (PSO) and water cycle algorithm (WCA) based dynamic voltage restorer (DVR) to augment the low voltage ride through (LVRT) performance of a hybrid renewable energy system (HRES). Moreover, FACT equipment like the dynamic voltage restorer (DVR) is deployed to boost the quick responsiveness of compensation and good transient performance of HRES. Due to numerous disturbances brought on by WECS' nonlinearity, the best tuning of a PI controller for DVR control is investigated to match the LVRT requirement of the HRES. The design incorporates a battery energy storage system (BESS) that is connected over the DC terminals of the DVR to improve the compensating capabilities by regulating the D-Q axis voltage signal to control the voltage source converter gate signals. In comparison to DVR alone, the suggested technique increases the DC-link voltage and PCC voltage by 44% and 4.6 %, respectively. MATLAB simulation results show that the BESS-enabled PSO DVR performs better in all respect for the compensation of voltage sag and makes the system self-LVRT capable.

Multi-objective planning for voltage sag compensation of sparse distribution networks with unified power quality conditioner using improved NSGA-III optimization

Aiming at the voltage sag compensation of the long-distance sparse distribution network, this paper proposed a multi-objective optimization method based on improved S-CDAS dominance and NSGA-III genetic algorithm. Firstly, aiming at the difficulty of solving the power flow for distribution network with unified power quality conditioners (UPQC), an alternating iteration algorithm of power flow calculation was presented. Secondly, this paper proposed an adaptive controlling of dominance based on extreme solutions. The algorithm dynamically fitted the Pareto frontier according to the extreme solutions in the iterative process to strengthen the dominance region of the optimal set. The algorithm results showed that the improved S-CDAS dominance could improve the convergence speed and result of NSGA-III algorithm while preserving its diversity. Finally, through PSCAD simulation, the effectiveness of the proposed algorithms was proved, and the effect of UPQC on voltage sag in long-distance sparse distribution network was verified. In conclusion, the UPQC configuration method proposed in this paper can consider the diversity of convergence direction and speed, which plays an effective role in the voltage sag compensation of long-distance sparse distribution network.

Modelling and Simulation of Fault Current Limiter in Single and Three Phase Line for Compensating Voltage Sag a Review

A high potential fault current levels in power grid is not a new approach, and should eventually exceed, the limitation of short-circuit-current would be existed protection devices. Different to pricey system upgrades of protection devices, Fault Current Limiters (FCL’s) gives an additional cost efficient solutions to forestall recent protection devices and different instrumentality on the system from being broken by excessive fault currents. Evaluation of short circuit faults may usually the origin of voltage sags at a purpose of common coupling point (PCC) during a power network, the extent of the voltage sag is proportional to the short current level, reducing the fault current level at intervals the networks will scale back voltage sags throughout faults and defend sensitive loads that are interfaced to a similar PCC. The planned structure prevents voltage sag and counter balance the phase-angle of the PCC once fault prevalence. As a result, different feeders which are interlinked to the sub-station PCC can have attentive power quality. During this paper a high performance 3-phase fault current electrical model is planned. A Matlab/Simulink model is developed and simulation results are conferred.

Voltage sag compensation at load side in armor fighting vehicles using ultra capacitor

PurposeThe purpose of this paper rapid development of various voltage sag compensation techniques in DC bus using ultra-capacitors (UCs) provides satisfactory results when compared with required peak power demand for shorter duration. Later, UCs have been used as floating capacitors [1] [2]. Various UCs are available based on internal resistances which also rely on its manufacturing materials, similar to double layer capacitors.Design/methodology/approachThis paper demonstrates UCs based voltage sag compensation at load side under different working modes of hydraulic pack (HP) in an armored fighting vehicle (AFV). The main sources to supply the HP are 24 V, 400 Ahr battery bank and 20 kW main generator. HP is considered to be the highest power load of a system. 2,500 A inrush current was drawn by HP during initial conditions, and also, this system works in both elevation and azimuth mode. Voltage sag has been varied from 15 to 24 V for different modes. But as per the military standard, electrical systems should operate between 18 and 32 V DC. Because of insufficient terminal voltage, required energy cannot be attained and supplied to the loads. The proposed topology compensated the voltage sag and maintains nominal voltage on a DC bus. The devised circuit has been verified under all possible operating loads such as continuous, intermittent and momentary. The same has been simulated using MATLAB/Simulink and was experimentally verified. The minimum voltage maintained in a DC bus is 22.2 V in simulation, while experimentally, it was 24.2 V.FindingsFor getting higher percentage of efficiency, secondary energy system configuration, mainly designed for electrical vehicles, is needed. It was implemented and same was tested with the fighting vehicle system[1]. The proposed configuration comprises of bank of an UC and a battery bank. The system was finally implemented in AFVs.Originality/valueThe goods vehicles made of UCs can hold very minimum energy because of minimum density of energy. The modified AFV can have minimum charging as well as discharging of rate of energy and, thus, power[3][4]. Thus, the proposed idea of modified vehicle system has influence over significant change in the state of charge.

“Enhance the Power Quality of the Smart Grid System by Using Advance UPQC.”

Abstract: The UPQC is the grouping of a DVR and D- STATCOM which perform series, shunt compensating and phase shifting at the same time. This is capable to control the PQ with leading and lagging reactive and real power flow through a particular route with enhance the system stability. The salient options of UPQC device are its multiple management functions, like voltage management, transient stability improvement & damping oscillation. Voltage sag and swell compensation is important for secure system operation. This is a multivariable versatile AC transmission systems controller. In this work UPQC is excited by PV array with DC link capacitor. In the SG using PMU and flow meter, measures the phase and related data, from this data of analysis centralized controller determine the harmonics amplitude and phase. At fault condition UPQC mitigate the fault with simultaneous or individual operation of series-shunt converters. At the presence of harmonics this two converter works simultaneously and optimized the harmonics injected by the UPQC, the centralized controller calculates the switching angle for same magnitude with opposite phase harmonics and inject into the system. These two components eliminate each other and make the grid approximately harmonics free with mitigate the active and reactive power problem. Keywords: UPQC, DSTATCOM, DVR, PV array, Power Quality

Compensating Voltage Sag in Single Phase and Three Phase Lines Using Fault Current Limiter

Voltage sag compensation is provided on both sides of the Point of Common Coupling (PCC) by using FACTS Devices (STATCOM, APF, DSTATCOM, DVR, UPFC) and FCL. The FACTS dev ices provide compensation on input side and FCL provides compensation on output side. A sensitive load is considered at output side of PCC. This paper presents a component called Fault Current Limiter (FCL) in three phase lines. The main objective of the designed component is to protect the sensitive load from the shunt faults. The compensation is being provided at output side of PCC. Load voltage reduces upon the occurrence of shunt fault. The planned structure prevents voltage sag and counter balance the phase-angle of the PCC once fault prevalence. As a result, different feeders which are interlinked to the sub-station PCC can have attentive power quality. During this paper a high performance 3-phase fault current electrical model is planned. The analysis and design is carried out in MATLAB with SIMULINK.

Review on Compensating Voltage Sag in Single Phase and Three Phase Lines Using Fault Current Limiter

A high potential fault current levels in power grid is not a new approach, and should eventually exceed, the limitation of short-circuit-current would be existed protection devices. Different to pricey system upgrades of protection devices, Fault Current Limiters (FCL’s) gives an additional cost efficient solutions to forestall recent protection devices and different instrumentality on the system from being broken by excessive fault currents. Evaluation of short circuit faults may usually the origin of voltage sags at a purpose of common coupling point (PCC) during a power network, the extent of the voltage sag is proportional to the short current level, reducing the fault current level at intervals the networks will scale back voltage sags throughout faults and defend sensitive loads that are interfaced to a similar PCC. The planned structure prevents voltage sag and counter balance the phase-angle of the PCC once fault prevalence. As a result, different feeders which are interlinked to the sub-station PCC can have attentive power quality. During this paper a high performance 3-phase fault current electrical model is planned. A Matlab/Simulink model is developed and simulation results are conferred.

Compensation of Sag and Swell Voltage by Using Dynamic Voltage Restorer

There is an introduction to the dynamic voltage restorer in this paper that discusses voltage sags and swell. Also, it is about the compensation of voltage sag and swells. The power quality requirement is one of the most important issues. The power quality problem includes voltage sag, swell, notch, spike, transient, etc. Voltage sags and swells are serious problems requiring immediate attention. In order to compensate for them, there are a number of methods to employ. One of the most effective methods of sag and swell compensation is DVR, which is used in low voltage and medium voltage applications. This paper deals with the compensation of sag and swell voltage. The sag and swell of voltage are compensated by using DVR.. Then the operation of hardware and elements in DVR is explained with their rating dynamic voltage restorer. Keywords - Dynamic Voltage Restorer, Voltage Sag and Swell, Voltage Source Converter, Power Quality.