Dynamic Voltage Restorer System Research Articles

Power quality investigation with multilevel inverter by photovoltaic-fed dynamic voltage restorer

ABSTRACT In this research endeavor, a novel approach has been presented to enhance the power quality through a Photovoltaic (PV)-based Dynamic Voltage Restorer (PV-DVR). The proposed work is designed to address voltage fluctuations, flicker, and harmonics within medium or low voltage micro-grid systems. Unlike existing DVR systems that often neglect injected harmonics and converter losses, in the proposed work there is an integration of a PV-fed multilevel inverter system employing Selected Harmonic Elimination and Moderation-based Pulse Width Modulation (SHEAM-PWM). This innovative configuration, coupled with a DC – DC boost converter and a series injection transformer, not only aims to alleviate voltage stress on devices but also optimizes the number of switches to minimize switching losses. The proposed setup successfully reduces the overall voltage Total Harmonic Distortion (THD) to a significant extent, delivering superior dynamic performance. To determine optimal switching angles for the SHEAM-PWM technique, ensuring the elimination or mitigation of the maximum number of harmonics from the output voltage waveform, we employ the Biogeography-Based Optimization (BBO) approach. The computation of these angles is performed offline to eliminate lower-order harmonics, and the results are stored in the microcontroller’s memory using mixed model equations for online applications. The efficacy of our proposed method is demonstrated through both simulation and experimental validation in a real-time laboratory system. The simulation and experimental results obtained underscore the potential utility of our technique for Dynamic Voltage Restorer (DVR) applications, particularly those requiring low harmonic injection. The proposed method introduces a comprehensive and innovative solution for power quality enhancement, combining PV technology, multilevel inverter systems, and advanced optimization techniques. The proposed PV-DVR system exhibits promising results, showcasing its potential for practical implementation in residential micro-grid systems with a focus on minimizing harmonics and ensuring efficient grid compensation.

A Robust approach for mitigating load voltage imbalances using glowworm swarm optimizer for power quality enrichment

This paper addresses the paramount issue of maintaining optimal power quality in power system networks to ensure reliable operations. The paper introduces an innovative solution that effectively mitigates power quality challenges stemming from disturbances like voltage sag/swell events and harmonics. The approach combines a Dynamic Voltage Restorer (DVR) unit with a Solar PhotoVoltaic (PV) system, incorporating advanced control strategies. Leveraging the Glowworm Swarm Optimizer (GSO) Tuned Proportional-Integral-Derivative (PID) Controller and the Versatile Control on Synchronous Reference Frame (VCSRF) theory, our system achieves exceptional results. Extensive MATLAB/Simulink simulations demonstrate the superiority of the proposed DVR system over traditional PID, GA, PSO, and SSA controller-based DVR systems. Notably, our approach achieves significant reductions in Total Harmonic Distortion (THD), with reductions of 5.27 % (PID), 3.14 % (GA), 1.29 % (PSO), 0.841 % (SSA), and 0.03 % (GSO-PID), underscoring its substantial effectiveness. Practical implementation further validates the improved THD performance. The paper's findings highlight the efficiency and potential of the integrated DVR unit with a solar PV system in effectively mitigating power quality issues. These results offer valuable insights for researchers and practitioners seeking advanced solutions to power quality challenges. Future research endeavors aim to optimize and expand this approach for diverse power quality improvement applications.

Sliding Mode Control of a Four-Leg Dynamic Voltage Restorer in a Natural Reference Frame

This paper focuses on designing a sliding mode control (SMC) for a dynamic voltage restorer (DVR) using a four-leg voltage source converter and its output filters in the natural reference frame. The coupling of filter-capacitor voltages through the control inputs of the DVR system leads to cross-coupling in the dynamics of conventional sliding variables with respect to four control input variables, making the design of SMC using Lyapunov stability criteria difficult. To overcome this, a new sliding variable for each converter leg is proposed, which is a function of the respective filter-capacitor voltage and a fictitious voltage that depends on the converter neutral-point voltage (NPV). This allows control of both the compensator voltages and the converter NPV using the proposed scheme. This paper also presents the calculation of the optimum sliding coefficient to maximize the sliding existence region for a four-leg DVR. The performance of the proposed control scheme is experimentally validated under various operating conditions using a laboratory prototype of a four-leg DVR.

IMPLEMENTING ARTIFICIAL NEURAL NETWORK BASED DVR TO IMPROVE POWER QUALITY OF RUMUOLA-RUMUOMOI 11kV DISTRIBUTION NETWORK

The most vexing problem plaguing Rumuomoi's 11kV distribution network is voltage sag and swell, which degrades power quality. There has been no effective mitigation control implemented. The purpose of this research is to address the issue of power quality by implementing artificial neural network (ANN) control with an embedded dynamic voltage restorer (DVR). To begin, the artificial neural network is trained using the input and desired data obtained during simulation using a proportional integral (PI) controller. To limit the amount of data obtained during training, the Levenberg-Marquardt feed forward back method is utilized, and the result for each iteration is determined in Matlab software. The desired dynamic voltage restorer system was tested using a replicated model of Rumuomoi 11kV and it was determined that Bus 7 is 0.938p.u, Bus 8 is 0.9244p.u, Bus 9 is 0.9148p.u, Bus 10 is 0.9035p.u, Bus 11 is 0.8912p.u, and Bus 12 is 0.8811p.u, all of which exceeded the statutory limit condition of 0.95-1.01p.u. There were no bus voltage violations after network optimization with DVR, demonstrating that DVR is effective at enhancing power quality by removing voltage sag and swell in the distribution network.

Hybrid control mechanism-based DVR for mitigation of voltage sag and swell in solar PV-based IEEE 33 bus system

<p><span lang="EN-US">The power quality issues are raised due to sag/swell, which affects the overall performance of the grid-connected system. This study introduces the hybrid control mechanism based on a dynamic voltage restorer (DVR) to mitigate the sag and swell issues in the solar PV-based IEEE 33 bus system. The hybrid controller improves the dynamic performance and boosts the overall efficiency of the DVR system. The proposed work is also used to address the distribution system's voltage quality issues with minimal energy drawn out from the utility grid and effectively use solar energy. The sag and swell are introduced at the grid side and compensated at the load side by injecting DVR voltage. The proportional-integral (PI) controller followed by the fuzzy logic controller (FLC) is used to create the hybrid control mechanism for DVR. In this work, the solar PV system with DVR system is connected to the 29<sup>th </sup>location in the IEEE 33 bus system for performance realization. The hybrid control mechanism-based DVR provides 1.06% and 1.05% total harmonic distortion (THD) at sag and swell conditions for load voltage. The proposed work meets the IEEE 519 standards in terms of THD calculation. The proposed design compares with existing work and shows better THD reduction for load voltages.</span></p>

An Effective Transformerless PUC7-Based Dynamic Voltage Restorer Using Model Predictive Control

This paper investigates the performance of a seven-level Packed U Cell (PUC7) inverter-based transformerless Dynamic Voltage Restorer (DVR) topology under short-time voltage variations (voltage sags and swells). Unlike the existing multilevel inverter (MLI)-based DVR solutions, the proposed structure requires only one DC voltage source (suitable for PV-based DVR systems), one capacitor, and six switching devices to generate seven-level output voltage. Moreover, the studied topology is characterized by reduced cost and size due to the elimination of the injection transformer. The PUC7 inverter is controlled using a multi-objective (filtering current, compensating voltage, and PUC capacitor voltage controls) Model Predictive Control (MPC) strategy. Simulation and implementation tests are carried out to demonstrate the high performance of the proposed DVR at steady-state and during transient conditions, while keeping the load voltage unaffected by the disturbances in the grid voltage.

Integration of renewable energy sources in the dynamic voltage restorer for improving power quality using ANFIS controller

Nowadays, grid power loss and power quality deterioration are causing many problems, especially for sensitive uses such as data centers, airports, healthcare, banking, insurance, and telecom. These issues must be resolved through energy continuity coverage and optimization. Dynamic voltage restorers (DVR) are generally used to mitigate network voltage disturbances and maintain a constant voltage value between load terminals for a short and limited duration due to limited energy storage facilities. However, this paper's proposed (DVR) system controlled by the adaptive-network fuzzy inference system (ANFIS) controller can compensate for prolonged power quality disturbances by integrating a hybrid renewable energy system (HRES) managed using classical Proportional Integral (PI) controller power management. This paper proposes a new (DVR) topology coupled with a hybrid renewable energy system (HRES) to exploit free and clean energy, consisting of a solar panel, a PEM fuel cell, and a battery storage device connected through DC-DC converters to a DC transmission, the obtained results from the simulation process of the proposed DVR system in the environment of MATLAB / Simulink showed the ability to eliminate sag that exceeded 0.9 pu in a period of more than 3 min and swells that exceeded 1.2 pu in a period that exceeded one minute. In comparison, the load voltage's total harmonic distortion THDv was reduced from 29% to 5%, and the source current total harmonic distortion THDi from 30.25% to 2.79%.

Design and simulation of dynamic voltage restorer (DVR) for power quality improvement

Power quality (PQ) is one of the main issues faced in the present era. The PQ issues such as voltage sags, swells, harmonics, and unbalance as well as the impact on sensitive loads are often occurred in any power distribution system. To tackle the issues, a powerful dynamic voltage restorer (DVR) is commonly installed. However, the existing control algorithms for DVR are found to be complex, potentially increases computational burden to the controller. Therefore, in this paper, a new simplified control algorithm which utilizes the strengths of synchronous rotating frame (SRF) and phase-locked loop (PLL) concepts, is proposed to better manage operation of DVR. The DVR system is modelled and simulated by using MATLAB/Simulink platform. Performance of the newly proposed algorithm for DVR is tested in three-phase system with voltage sags, swells, harmonics and unbalances conditions. From the findings, it can be concluded that the proposed algorithm for DVR which installed in a three-phase power distribution system effectively mitigated the voltage sags, swells and unbalances conditions and, for harmonics condition, it is found to be able to minimize and contain the harmonic contents within the acceptable level.

Hybrid Renewable Energy Source Combined Dynamic Voltage Restorer for Power Quality Improvement

In this paper, the hybrid photovoltaic-thermoelectric generator (PV-TEG) combined dynamic voltage restorer (DVR) system is proposed for the power quality disturbances compensation in a single-phase distribution system. The stable and precise level of input voltage is essential for the smooth and trouble-free operation of the electrically sensitive loads which are connected at the utility side to avoid system malfunctions. In this context, the hybrid PV-TEG energy module combined DVR system is proposed in this paper. With the support of the hybrid energy module, the DVR will perform the power quality disturbances compensation effectively with needed voltage and /or power. In the proposed system, the PV and TEG energy sources are connected electrically in series to produce adequate voltage for the DVR operation and the fractional factor-based variable incremental conduction (FFVINC) maximum power point tracking (MPPT) control algorithm is employed to extract the possible maximum power from the PV array. The intelligent fuzzy logic controller (FLC) is chosen for implementing the MPPT control algorithm. The half-bridge voltage source inverter (VSI) circuit and in-phase voltage compensation technique are used in the DVR for better power quality disturbances compensation. The performance and usefulness of the proposed DVR system are investigated by an extensive simulation study with four different modes of operation, the study results are confirmed that the proposed system promptly identifies the power quality disturbances for compensation. Moreover, the investigation proved that the combined PV and TEG energy module can provide better energy efficiency in converting solar irradiation into electricity.

A coordinated management scheme for power quality and load consumption improvement in smart grids based on sustainable energy exchange based model

This paper presents a contrived framework that accompanies the power quality improvement (PQI) and demand-side management (DSM) in the case of recurring voltage-related problems. The illustrative implementation of the proposed framework necessitates two antecedents. First, a comprehensive mathematical formulation of the electrical power for a dynamic voltage restorer (DVR) is presented. Second, a model is developed to analyze the energy exchange during the voltage disturbances. Afterwards, the performance of a DVR system is simulated and a scrutinization is accomplished about the effect of power exchanged by a DVR with distribution system on the load factor. Meanwhile, a modified mathematical model of demand response (DR) is developed to derive the different DR methods with the purpose of load profile improvement (LPI). The simulation results reveal that the DVR operation may decrease the load factor from +3.56% to −3.20% of the usual load factor. Furthermore, in some situations, the DR outcomes might be obliterated by PQI. The implementation of proposed framework demonstrates the load factor can be enhanced up to 7.46% by proper DR strategy adoption.

Compensation of Voltage Sags and Swells Using Dynamic Voltage Restorer Based on Bi-Directional H-Bridge AC/AC Converter

In this paper, the compensation of voltage sags and swells using a dynamic voltage restorer (DVR) based on a bi-directional AC/AC converter is presented for stabilizing single-phase AC line voltage. The H-bridge AC/AC converter with bi-directional switches and without bulk capacitor is adopted as the power topology of the proposed system. The proposed novel topology of DVR is adopted to compensate both voltage sag and swell conditions. Additionally, the power factor is closed to unity because a bulk capacitor is not required. The inner and outer loop control is proposed to improve the response with gain scaling; gain control is adopted to reduce the overshoot. Finally, a 2 kVA prototype has been implemented to verify the performance and accuracy of the control method for the DVR system. The peak efficiency of the system is up to 94%, and it can compensate 50% voltage swells and 25% voltage sags.

SOFC-Supported Hybrid PSOGSA-Optimized Dynamic Voltage Restorer for Power Quality Enhancement

A novel optimal method of a Dynamic Voltage Restorer (DVR) supported by solid oxide fuel cell (SOFC) and its simplified topological structure are proposed. DVR is a power-electronic converter-based device, and the objective of the DVR control system is to minimize supply voltage variations at the load terminals. This is attained by generating a compensating voltage at the series injection transformer. Conventional controllers are mathematical model-based; also, the particular system varies widely, and nonlinear factors make the PI controller tuning more challenging to some extent. As a result, an intelligent PI optimization control method is essential. This paper proposes Hybrid PSOGSA to search for optimal values of two PI control parameters for the [Formula: see text]–[Formula: see text]-axis components by considering a novel bi-objective function. The performance of the test system is analyzed for five test scenarios using the proposed PI controller with SPSO-optimized and Ziegler–Nichols tuning methods. DVR system provides an excellent control performance in the transient and steady states for compensating the sensitive load voltages with almost zero steady-state errors. Simulation results show that the proposed approach can provide improved performance than PSO-optimized and classical PI controllers for the power quality indices measured.

Grid Interfaced Windfarm Using Dynamic Voltage Restorer for Power Compensation with Pv Fed Sepic Converter

In this paper, the wind energy generation farm is connected with the grid system. The dynamic voltage restorer (DVR) is installed to control the grid side’s under and overvoltage. The photovoltaic (PV) system is installed in the DVR system, and the voltage of the grid over and under voltages is also addressed to achieve the proposed system’s high efficiency. The grid voltage compensation is harvested from PV and injected through the DVR. The boost converter is used in the existing systems to improve the available power from PV. In this system, the SEPIC converter is used to achieve high voltage gain from the PV plant to improve DC link capacitor voltage which is the inverter input source. The DVR based wind energy farm using PV with SEPIC system results are achieved in MATLAB/Simulink.

Dynamic Voltage Restorer Integrated with Photovoltaic-Thermoelectric Generator for Voltage Disturbances Compensation and Energy Saving in Three-Phase System

The dynamic voltage restorer (DVR) combined with a photovoltaic–thermoelectric generator (PV-TEG) system is proposed for voltage disturbance compensation in the three-phase four-wire distribution system. The PV-TEG hybrid energy source is used in the DVR system to improve the system ability for deep and long-period power quality disturbance compensation. In addition, the DVR will save grid energy consumption when the hybrid PV-TEG module generates sufficient power to meet the load demand. An enhanced variable factor adaptive fuzzy logic controller (VFAFLC)-based maximum power point tracking (MPPT) control scheme is proposed to extract the maximum possible power from the PV module. Since the PV and TEG combine a hybrid energy source for generating power, the DVR can work efficiently for the voltage sag/swell, outage compensation, and energy conservation mode with minimum energy storage facilities. The in-phase compensation method and the three-leg voltage source inverter (VSI) circuit are chosen in the present system for better voltage and/or power compensation. To confirm the effectiveness of the proposed hybrid PV-TEG integrated DVR system, a simulation-based investigation is carried out with four different operational modes with MATLAB software. The study results confirm that the proposed DVR system can compensate power quality disturbances of the three-phase load with less total harmonics distortion (THD) and will also work efficiently under energy conservation mode to save grid energy consumption. Moreover, the proposed VFAFLC-based control technique performs better to achieve the maximum power point (MPP) quickly and accurately, thereby improving the efficiency of the hybrid energy module.

Control of transformerless T-type DVR using multiple delayed signal cancellation PLL under unbalanced and distorted grid condition

In the near future, the power system network may experience severe voltage distortions due to association of renewable energy sources (RES), and the large penetration of power electronic based loads into the microgrid. To protect sensitive loads from these distorted and unbalanced grid conditions, the commonly used dynamic voltage restorer (DVR) requires effective control algorithms. The effective control algorithm comprises a controller, and accurate estimation of grid phase angle/frequency, and magnitude, thereby the reference DVR voltage is accurately estimated. The synchronous reference frame based phased locked loop (SRF-PLL) is commonly used for phase angle estimation. However, during unbalanced, distorted, and dc-offset conditions, the performance of SRF-PLL is unsatisfactory. To improve its performance, it is cascaded with prefilters such as dual second order generalized integrator (DSOGI), cascaded delayed signal cancellation (CDSC), and multiple delayed signal cancellation (MDSC). Among these prefilters, MDSC has superior performance under all grid conditions with less delay time and memory requirement. In addition to an effective control algorithm, the DVR system requires high power density converters. The power density of the system is increased using transformerless T-type converter. In this paper, the effectiveness of MDSC-PLL for the transformerless T-type converter based DVR is evaluated in MATLAB/Simulink for various grid conditions such as voltage sag/swell, unbalance voltage sag/swell, harmonics, and dc-offset.

Power Quality Enhancement Using Dynamic Voltage Restorer (DVR)-Based Predictive Space Vector Transformation (PSVT) With Proportional Resonant (PR)-Controller

In the power distribution system, the Power Quality (PQ) is disturbed by the voltage sag and swells. The Dynamic Voltage Restorer (DVR) is used to enhance various PQ problems like voltage sag, swells, and Harmonics. The previous Intrinsic Space Vector Transformation (ISVT) control techniques with DVR system, to compensate the power quality issue. It produced a steady-state error, low efficiency, and high THD. The SMES based DVR has provided excellent results in overcoming these issues. The energy is stored by DVR through a storage element, which takes alternate energy from a Solar PV cell. The Maximum Power Point Tracking (MPPT) based P&O algorithm is implemented to equalize the solar power. The Voltage Source Inverter (VSI) generates the reactive power, which has to be compensated with the help of Pulse Width Modulation (PWM) and the feedback control loop are essential to enhance the injection of reactive power to the line. Due to this reason, a proposed Predictive Space Vector Transformation (PSVT) control-based DVR is implemented. It analyzes the variation of power on the distribution side and generates the proper feedback control to the inverter systems. In the instant of voltage injection to the line with the help of DVR, the phase angle mismatch happens which is not synchronized reactive power to the grid. Due to the non-synchronization of reactive power, more harmonic distortion is generated. A Proportional Resonant (PR) controller is introduced, which is Proportional Resonant (PR) current controller. The current injected by the inverter into the grid in phase with the grid voltage maintain constant with unity power factor. The PR controller design is cascaded with a harmonic compensator to mitigate low order odd harmonic components present in the output current of VSI and minimize the total harmonic distortion (THD). The performance of the proposed is evaluated using MATLAB 2017b software.

Modified Topology for Three-Phase Multilevel Inverters Based on a Developed H-Bridge Inverter

This paper proposes a modified three-phase inverter from the developed H-bridge structure having multilevel functionality. The proposed topology can generate 7-levels of phase voltages and 13-levels of line voltages. Simple control methods such as fundamental frequency control method can be applied to the proposed topology. By adding three single-phase transformers, galvanic isolation is created for use in three-phase Dynamic Voltage Restorer systems. The proposed three-phase inverter utilizes less number of components; dc sources, semiconductor switches and driver circuits. Lower rated power switches with reduced blocking voltages are also used. These attributes make the proposed topology less complex in-terms of architecture and control. Comprehensive analysis of the proposed three-phase multilevel inverter and other presented topologies are investigated with respect to levels of output voltage, driver circuit quantity, dc voltage count, total component quantity and standing voltage. Details of the appropriate control technique employed is explained. Finally, practicability of the proposed inverter is validated by simulation using EMTDC/PSCAD software and experimental prototype.

RETRACTED ARTICLE: Use of neural network based DVR for the reduction of power quality issues in composite micro-grid

Most of today’s every power system networks deals with a serious scenario of Power quality. This problem had ever more observed with the advent of practical hardware, in which it will carry out serious impact in the eminence of power supply in to the micro-grid networks. Matter by reason of power quality, it is produced and critical to a non-common normal current and voltage re-emergence. It takes with reference to the distress of sophisticated electronic gadgets and renewable vigor sources. The predominant matter is centers to the voltage enlargements and dips. In this paper the instigator introduces a precise method for the bulge of voltages and dips. In the direction of revise the topic pointed out above for modified power types of electronic cog is embraces. Solitary, dynamic voltage restorer (DVR), is a leading progressed control hardware that can be utilized in micro-grids. If any uncertainty produced in the micro-grid DVR act as most favorably to ease the power quality problems. This job clarifies the MATLAB consequences of a dynamic voltage restorer (DVR) demonstrating with investigation. Particular form of controller’s similar to PI and NN controller like (proportional integral and neural network) is utilized in this DVR system. In this system procedure, DVR NN controller actualizes modified through the conventional PID-controller can be used examine a builded Composite micro grid system with Renewable sources. The newly developed controller is faster than traditional process initiated controller. By the use of MATLAB replication tools, presentation of the system shall be considered. To find the performance of the suggested NN based DVR which is simulated for the power loss reduction, power factor correction, and active and reactive power flow control. From the simulation results, NN based DVR is better compared to PI based DVR.

Compensation of voltage‐based power quality problems using sliding mode observer with optimised PI controller gains

This study discusses a control algorithm for dynamic voltage restorer (DVR) based on sliding mode observer (SMO) with an optimisation-based proportional integrator (PI) tuning to compensate the voltage related power quality problems. In this work, a three-phase VSC-based topology of DVR is selected with a self-supported capacitor. This DVR configuration using the proposed control algorithm has been used for mitigation of unbalance, sag, and swells in the supply voltage. The estimation of grid parameters in undesirable situations based on the exosystemic model are the advantages proposed control. New nature-inspired optimisation algorithm named as Harris hawks optimiser (HHO) has been applied to obtain the PI gains in the control algorithm to eliminate the time required for the tuning process. The main advantage of HHO is the avoidance of local minima and exploration and exploitation features of the algorithm. DVR system with a combination of SMO-based control algorithm along with HHO optimised PI controllers have been developed in MATLAB/Simulink and tested for above said voltage-based disturbances mitigation in the supply voltage.

Optimal Fuzzy Control of Nonlinear Dynamical Systems Using Evolutionary Algorithms

Goal of this research is to produce a controlling voltage for Pulse Width Modulation (PWM) generator so that its Total Harmonic Distortion (THD) characteristic is reduced and Dynamic Voltage Restorer (DVR) compensates function of the system against error as well as turbulence in such a way that the end user has no trouble with supplied voltage. In this study, a DVR system has been utilized which is capable of counteracting adverse effects of changing voltage against sensitive loads. Continuous and stable supply of energy is the most important goal in serviceability of electrical networks. Turbulence in distribution networks causes disturbances in level and quality of the voltage. To eliminate destructive effects of these disturbances especially over sensitive users, one could use compensator devices. So, a PSO-Fuzzy controller has been employed to optimize SAG characteristics of voltage of the sensitive load. Simulation results obtained in this study, considering the complicated and nonlinear nature of DVR system, demonstrates efficiency of proposed PSO-Fuzzy controller in improving behavior of the dynamic voltage restorer introduced to the network for the purpose of eliminating destructive effects of imminent disturbances over sensitive users. Keywords:Fuzzy Controller; Evolutionary Algorithms; Nonlinear Dynamical Systems;