Power Quality Compensator Research Articles

Performance evaluation of solar-PV integrated hybrid fuzzy-logic controlled multi-functional UPQC for enhancing PQ features

To improve distribution system voltage and current quality, a newly built solar-PV system connected multi-functional universal power quality compensator (MFUPQC) has been extensively used. The proposed MFUPQC mitigates both load and source-side concerns in a three-phase distribution system. Furthermore, as part of the distributed generation scheme, active power from solar PV is injected into the grid or source when solar PV is available. In this context, the proposed MFUPQC was tested in both PQ enhancement and DG integration modes using a feasible control scheme. The proportional-integral controller is used for shunt- voltage-source inverter (VSI) DC-link control, which is not suitable for regulating DC-link voltage at the desired level due to incorrect gain value selection. In this work, an intelligent hybrid-fuzzy-logic DC-link control of MFUPQC evidences the intelligent knowledge base for better regulation of power-quality issues. The suggested hybrid fuzzy-logic controlled MFUPQC device's performance for both power quality (PQ) improvement and DG integration is validated using the MATLAB/Simulink software tool, and simulation results are provided with an appealing comparison analysis.

A new-fangled connection of UPQC tailored power device from wind farm to weak-grid

A significant portion of wind power conversion systems worldwide comprise wind farms (WFs) that use Squirrel Cage Induction Generator (SCIG) and are directly linked to the power grid. In facilities that generate electrical energy at a moderate level, WFs are connected by means of distribution systems that use medium voltage (MV). It is not uncommon for such a system to produce a scenario in which the amount of electricity generated corresponds to the grid’s transit volume. When a wind farm’s wind power generation system is connected to a weak grid, the lack of potential control of the Point of Common Coupling (PCC) is a primary issue. This strategy is called a “Wind Farm with Weak Grid Connection.” Therefore, the amalgamation of weak grids, fluctuating electricity from wind, and variations in load on the system cause disruptions in the PCC voltage, further degrading the Power Quality (PQ) and the WF stability. Either the control method at the production level or the compensating strategies at the PCC level can improve this situation. If wind farms are built on SCIG and are directly linked to the grid, it is essential to utilise the last substitute. The technology known as Custom Power Devices (CUPS), proved extremely helpful for this type of application. This study presents a compensation technique based on a specific CUPS device, known as the Unified Power Quality Compensator (UPQC), as a possible solution. The potential terminals of WF needed to be regulated, and the voltage fluctuations on the grid side required to be reduced, so a custom-made control strategy for the UPQC device was designed internally. The control of power, such as active and reactive in the UPQC’s series and shunt converters, as well as the transmission of power via the UPQC DC-Link between converters, are the foundation of the internal control strategy that has been developed. Compared to other bespoke tactics that use reactive power, this strategy increases the UPQC’s capability to provide compensation. The suggested study calculates THD using a FUZZY controller. The results are compared to PI controller results. Simulation findings show how the suggested compensating strategy can minimise THD values and improve wind farm power and stability. The simulations suggest that the proposed compensating strategy enhances WF power and stability.

Fusion Data Management and Modeling Techniques in Power Quality Compensation Using SAPF

The development of transportation today encompasses a broad range of technological applications that occasionally present new challenges arising from difficulties that require solutions. The article analyzes the difficulties in electric trains concerning the compensation of electric power quality in a traction system using a parallel active power filter (SAPF). From the literature review of several studies, the test distribution system in a distribution network for an electric train system is analyzed, with a variable load and harmonic content. The estimation and control technique used in the SAPF to compensate for the harmonic content and reduce the reactive power at the output of a traction substation is described. A data fusion management strategy is employed in the analyses, demonstrating the system's effectiveness.

A Simulation Analysis of Grid-Connected DSTATCOM with PWM Voltage Control and Hysteresis Current Control for Power Quality Improvement

Abstract The DTSTACOM is a power quality compensator that can be used in the distribution grid to compensate the demand of reactive power, which can be produced by different linear and non-linear loads. In this process, the control method of DSTATCOM is one of the key factors influencing the performance of DSTATCOM. This study aims to analyse the effect of two modulation schemes, Pulse Width Modulation (PWM) and Hysteresis Current Control (HCC), under several conditions. The proposed modelling approach and Synchronous Reference Frame (SRF) theory are used to verify reactive power compensation and total harmonic distortion (THD). Further, PWM and Hysteresis Current Control (HCC) with proportional-integral (PI) controller simulated in MATLAB for different cases, and percentage THD was calculated to prove the effectiveness of the proposed method for the control of reactive power and THD with grid-connected DSTATCOM. The results presented here justify that the HCC controller can be better than the PWM method to generate the PWM pulses for reduction of harmonics under various conditions of DTSTACOM to compensate the reactive power. Additionally, the simulation was performed to check the efficacy of the projected method to reduce THD by varying the current control band of HCC.

A Novel Three-Phase Multiobjective Unified Power Quality Conditioner

The decarbonization of the economy and the increasing integration of renewable energy sources into the generation mix are bringing new challenges, requiring novel technological solutions in the topic of smart grids, which include smart transformers and energy storage systems. Additionally, power quality is a vital concern for the future smart grids; therefore, the continuous development of power electronics solutions to overcome power quality problems is of the utmost importance. In this context, this paper proposes a novel three-phase multi-objective unified power quality conditioner (MO-UPQC), considering interfaces for solar PV panels and for energy storage in batteries. The MO-UPQC is capable of compensating power quality problems in the voltages (at the load side) and in the currents (at the power grid side), while it enables injecting power into the grid (from the PV panels or batteries) or charging the batteries (from the PV panels or from the grid). Experimental results were obtained with a three-phase four-wire laboratory prototype, demonstrating the feasibility and the large range of applications of the proposed MO-UPQC.

Robust fault‐tolerant design for LC‐coupling hybrid active power filter

AbstractIn this paper, an open‐circuit fault‐tolerant topology of LC‐coupling hybrid active power filter (LC‐HAPF) and its control strategy are proposed at the switch level, which can greatly improve the reliability of the system. The proposed structure has a contactor between the midpoint of each bridge arm and the negative bus of the dc‐link capacitor. When a single‐phase fault occurs, the proposed LC‐HAPF can be reconstructed into a three‐phase four‐switch system to compensate for the harmonic and reactive power, while the power quality compensation effect is hardly affected. When a two‐phase fault occurs, the operation of the normal bridge arm is not affected, and the two faulty bridge arms can suppress harmonic current and compensate for a fixed reactive power through the passive filters. When the bridge arms all fail, the whole device acts as a passive filter to suppress the harmonic current of the load and to compensate for reactive power as well. Finally, the effectiveness of the proposed topology and its control strategy is verified by simulation and experiment results.

A novel ANFIS-controlled customized UPQC device for power quality enhancement

Power quality is crucial for the reliable and efficient operation of domestic and industrial loads. Nonlinear power electronic converter loads have increased in usage, which has led to a decline in both voltage and current quality. To overcome these power quality issues, a universal power quality compensator (UPQC) has been developed and integrated into the power distribution network. The UPQC comprises dual active power filters which are equipped with a DC-link capacitor. The voltage of the DC-link capacitor is controlled by a DC-link voltage controller. However, the conventional PI controller is not suitable for regulating voltage at a defined level due to inappropriate gain values. In this work, we propose an intelligent adaptive neuro-fuzzy inference system-based DC voltage controller for customized UPQC devices. The proposed control scheme aims to mitigate the existing power quality challenges by reducing the issues in classical controllers and incorporating intelligence knowledge with subjective decisions. Using the MATLAB/Simulink software tool, we have tested a customized UPQC device controlled by ANFIS for critical operation and performance. The simulation results are presented along with valid comparisons.

Distributed Control Scheme for Clusters of Power Quality Compensators in Grid-Tied AC Microgrids

Modern electrical systems are required to provide increasing standards of power quality, so converters in microgrids need to cooperate to accomplish the requirements efficiently in terms of costs and energy. Currently, power quality compensators (PQCs) are deployed individually, with no capacity to support distant nodes. Motivated by this, this paper proposes a consensus-based scheme, augmented by the conservative power theory (CPT), for controlling clusters of PQCs aiming to improve the imbalance, harmonics and the power factor at multiple nodes of a grid-tied AC microgrid. The CPT calculates the current components that need to be compensated at the point of common coupling (PCC) and local nodes; then, compensations are implemented by using each grid-following converter’s remaining volt-ampere capacity, converting them in PQCs and improving the system’s efficiency. The proposal yields the non-active power balancing among PQCs compounding a cluster. Constraints of cumulative non-active contribution and maximum disposable power are included in each controller. Also, grid-support components are calculated locally based on shared information from the PCC. Extensive simulations show a seamless compensation (even with time delays) of unbalanced and harmonics current (below 20% each) at selected buses, with control convergences of 0.5–1.5 [s] within clusters and 1.0–3.0 [s] for multi-cluster cooperation.

Design and Implementation of an Online Efficiency-Optimized Multi-Functional Compensator for Wind Turbine Generators.

In recent years, the penetration of wind power generation has been growing steadily to adapt to the modern trend of boosting renewable energy (RE)-based power generation. However, the dynamic power flow of wind turbine generators (WTGs) is unpredictable and can have a negative impact on existing power grids. To solve this problem efficiently, this paper presents a multifunctional WTG intelligent compensator (WTGIC) for the advanced power management and compensation of power systems embedded with WTGs. The proposed WTGIC consists of a power semiconductor device (PSD)-based bidirectional three-phase inverter module and an energy storage unit (ESU). In order to reduce system costs and improve reliability, efficiency, and flexibility, various control functions and algorithms are integrated via a modularized all-digital control scheme. In this paper, the configuration of the proposed WTGIC is first introduced, and then the operating modes and related compensation and control functions are addressed. An online efficiency optimization algorithm is proposed, and the required controllers are designed and implemented. The designed functions of the proposed WTGIC include high-efficiency charging/discharging of the ESU, real-time power quality (PQ) compensation, and high-efficiency power smoothing of the WTGs. The feasibility and effectiveness of the proposed WTGIC are verified using case studies with simulations in the Powersim (PSIM) environment and the implementation of a small-scale hardware experimental system with TI's digital signal processor (DSP) TI28335 as the main controller.

P2P Coordinated Control between SPV and STATCOM in a Microgrid for Power Quality Compensation Using LSTM–Genetic Algorithm

The deployment of a static synchronous compensator within a microgrid can facilitate voltage and reactive power regulation, leading to enhanced stability and reliability. Within a microgrid setting, the effectiveness of a STATCOM in balancing the power supply is influenced by several factors, including the system configuration, the operating conditions, and the specific requirements of the power grid. The capacity, response time, and magnitude of system disturbances also play a role in determining the STATCOM’s ability to balance the power supply. To ensure the successful integration of a STATCOM within a microgrid, coordinating the control system with other distributed energy resources (DER), especially when multiple control strategies are employed, can be a challenging task. Therefore, a meticulously designed control system is indispensable to guarantee the microgrid’s efficient and effective operation. The use of GA in LSTM tuning can accelerate the process of identifying the optimal hyperparameters for a specific task, obviating the need for time-consuming and computationally expensive grid searches or manual tuning. This method can be particularly advantageous when handling large data sets and complex models. In this paper, an attempt has been made to model the STATCOM to communicate with the microgrid, tuned using LSTM–GA, for the effective calculation of real and reactive power support during grid disturbances.

Design and simulation of monarch butterfly optimized SP-UPFC for power quality compensation

The super smart gridsare a kind of broad-area transmission network, which makes use of Flexible AC transmission system (FACTS)and helps to reduce greenhouse gas emissions while also maintaining the electricity infrastructure of various nations. The six-phase unified power flow controller (SP-UPFC) is a FACTS device that offers total stability to power system networks in the form of series and shunt compensations. The power quality compensation (PQC) operation using SP-UPFC is achieved by adopting the monarch butterfly optimization (MBO) algorithm. Here, shunt converters and series converters of parallel and series connection units are kept in sync with the help of master-slave synchronization. In addition, a coordination strategy is created for the SP-UPFC control protection system and the power grid protection, which improves the ride-through capability during a failure. In comparison to state-of-the-art methods, the simulation results reveal that the proposed MBO-optimizedSP-UPFC decreases total harmonic distortion (THD) and increases power factor.

Power Selective Control With Fault Tolerance of Multifunctional Inverter for Active Power Injection and Power Quality Compensation

This paper proposes a power selective control with fault tolerance of multifunctional inverter for active power injection and power quality compensation. The multifunctional inverter is widely researched, because the inverter capacity can be fully used to realize multiple functions. However, the inverter legs may have open-circuit fault during operation, affecting the realization of inverter functions and even causing the secondary fault. Following the early stage of fault detections, fault tolerance can be applied to inverters, in some cases, to prevent unexpected shutdowns. The fault tolerance control enables the inverter to be reconstructed to another steady state and operates normally under open-circuit fault. By reconstructing of the inverter, the non-faulty legs can prioritize and selectively inject active, reactive, and harmonic power, so as to realize the multifunction during the leg open-circuit fault. Finally, the simulation and experimental results are given to demonstrate the effectiveness of proposed power selective control with fault tolerance of multifunctional inverter for active power injection and power quality management.

A Residential Miniboost Photovoltaic Inverter With Maximum Power Point Operation and Power Quality Compensation

Among the exiting multifunctional photovoltaic (PV) inverters (MPVIs), the main challenges are low efficiency, undesired harmonic emission, and weak compensation capability. In this paper, a theoretical study via rotating phasor to the PV curves is firstly proposed to figure out the undesired harmonic emission puzzle in different PV inverters as well as to provide the foundation for PV inverters to achieve multifunction ability under varying load conditions. On the other hand, a single-phase time-sharing miniboost MPVI with different operation modes is proposed and operated under varying PV and load conditions in order to improve its efficiency and compensation capability without undesired harmonic emission. Corresponding control strategy and stability analysis are given. Finally, a 1.5-kW prototype is presented, benchmarked against harmonic emission issues, compensation capability, and efficiency. Experimental results clearly indicate that the proposed topology and control method can perform the active power injection and power quality compensation with better efficiency and avoiding harmonic emission into the grid dynamically.

Towards technical and economic feasibility of power quality compensators

Towards technical and economic feasibility of power quality compensators

Power Quality Compensation Strategy of MMC-UPQC Based on Passive Sliding Mode Control

While the unified power quality conditioner based on modular multilevel converter (MMC-UPQC) can be used for recovering power quality of voltage and current in high voltage grids, it is difficult to manage the power quality when the grid voltage imbalance is large. In this paper, a passivity-based control (PBC) combined with sliding mode control (SMC) is proposed for MMC-UPQC to improve the power quality under the unbalance of grid voltage in power systems. First, according to the structure of MMC-UPQC, the equivalent mathematical model is presented for unbalanced power grids. Second, the detection quantity is separated without phase-locked loop using a method of positive and negative sequence separation. Furthermore, a passive sliding mode control (PSMC) strategy is designed and applied to a multi-level and high voltage power quality compensation system. The proposed controller can improve the control accuracy of system parameters, response speed, and compensation effectiveness. Finally, the MATLAB/Simulink simulation and the real time laboratory (RT-LAB) based hardware-in-the-loop (HIL) experimental results show that the proposed PSMC strategy can compensate voltage and current rapidly and accurately, and the controller has strong robustness against system parameter changes.

Harmonics Extraction Scheme for Power Quality Improvement Using Chbmli-Dstatcom Module

In recent day’s power distribution system is distress from acute power quality issues. In this work, for compensating Power Quality (PQ) disturbances a seven level cascaded H-bridge inverter is implemented in distribution static compensator which protects power quality problems in currents. Distribution Static Compensator (DSTATCOM) aid to enhances power factor and removes total harmonic distortion which is drawn from non-linear load. The D–Q reference theory based hysteresis current controller is employed to generate reference current for compensation of harmonics and reactive power, additionally Probabilistic Neural Network (PNN) classifier is used which easily separates exact harmonics. In the meantime fuzzy logic controller is also used to maintain capacitor DC-link potential. When comparing to PI controller it decreases steady state time and reduces maximum peak overshoot. Cascaded H-bridge multilevel inverter converts direct current to Alternating current, through inductor opposite harmonics are injected in Power Control Centre reduces source current harmonics and reactive power. The implementation of CHBMLI in distribution STATic COMpensator simulation model is simulated by means of MATLAB.

DSTATCOM using model predictive control associated with LMS control

ABSTRACT In this paper, a type of variable step size LMS named weighted zero attracting variable step size (WZAVSSLMS) is equipped with the control algorithm for governing DSTATCOM. In WZAVSSLMS, the ability of zero attracting nature to a variable step size (VSSLMS) for improving convergence rate is observed. WZAVSSLMS algorithm-based fundamental extractor is developed to identify the fundamental quantity of the load current for a three-phase four-wire DSTATCOM with non-linear load in this work. This type of variable step size LMS has provided a concession for quick convergence rate and steady-state error. Precision and convergence of responses are accomplished by the learning rate control. As a result of these features over conventional LMS, the authors choose WZAVSSLMS based approach in well-known DSTATCOM system to compensate power quality issues. The fundamental extraction from the distorted load current constitutes the main divergences in the proposed study. Further, the Finite control set model predictive control (FCS MPC) of the distribution static compensator (DSTATCOM) using Weighted Aggregated Sum Product Assessment Solution (WASPAS) method is implemented.

A Transformerless Railway Power Quality Compensator Based on Cascaded H-Bridge Featuring Reduced Branch Capacity Requirement

Featuring high modularity, scalability and transformerless structure, cascaded H-bridge (CHB) based power quality compensator (PQC) is a promising power quality solution for railway power system (RPS). Firstly, branch rating requirements of the conventional CHB based PQCs for co-phase RPS are analyzed under two typical traction transformer schemes, i.e., the V-v scheme and the Scott scheme. Then, a novel CHB based PQC with a special wiring connection style of the Scott transformer is proposed, which achieves reduced total submodule quantity and total branch capacity compared with the conventional solution in V-v and Scott schemes. In addition, a branch current reference generation method is introduced for both branch energy balancing and power quality regulation, which avoids the complicated zero-sequence circulating current injection issue and thus facilitates controller implementation in practice. The effectiveness of the proposed CHB based PQC and the corresponding control strategy is verified by both simulations and experiments.

Robust control of adaptive power quality compensator in Multi-Microgrids for power quality enhancement using puzzle optimization algorithm

The primary purpose of this paper is to design a novel multi-microgrid connection that uses power compensation methods to improve voltage profiles and reduce harmonic distortions using specific compensation devices in low inertia systems. The utilized compensation device is an adaptive power quality compensator (APQC) which includes series and shunt compensators. Thyristor controlled series capacitor (TCSC) is used as a series compensator to alleviate the dynamic voltage profile as well as diminish transient voltage. A shunt active power filter (SAPF) is utilized as a shunt compensator to improve the power factor and lessen voltage and current harmonics. The TCSC has a power level of error of the PID controller, while the SAPF has a dynamic multi-level of errors of the PID controller. Further, the recent swarm intelligence-based puzzle optimization algorithm is employed to get the best self-tuning of the PID controller gains to reveal the act of the APQC typology. The efficacy of the presented APQC with the multi-level mechanism approach, assessed using Matlab/Simulink time-domain simulations, has been compared with the recently reported literature. Two operation modes are addressed, one for the island mode and the other for the grid-connected mode with significant renewable generation penetration and nonlinear loads. APQC successfully enhances the power quality of multi-microgrids (MMGs), according to theoretical research and simulation statistics. Finally, three comparative study assessments of numerous optimization approaches, with a unified power flow conditioner (UPFC), and with other series-shunt compensators like distributed power condition controller (DPCC) are proposed to attain efficacy and strength of the compensator.

Power Flow Numerical Assessment of a STATCOM iUPQC Utility Interface for Microgrids

The dual unified power quality conditioner (iUPQC) is an active filter that has been studied to be applied as utility interface in microgrid applications. It regulates the voltage of the microgrid side and controls the power flow between the grid and microgrid side. Besides that, ancillary functions to grid side has been proposed to extend its power quality compensation. This paper presents a detailed analytical and numerical analysis of the power flow of an iUPQC, which operates as an utility interface in microgrid applications with the extended function of STATCOM. It can compensate not only the disturbances at the load or microgrid side but also provides a RMS voltage regulation at the Point of Common Coupling (PCC), thus, providing reactive power to the grid. Moreover, the iUPQC power flow is evaluated considering the implementation of the power angle control (PAC), a technique used to share and equalize the power processed by each converter allowing the optimization of this conditioner. Therefore, this study can support the understanding of the power flow of the iUPQC operating as STATCOM, in order to share and optimize the available power in the iUPQC converters using PAC.