Unified Power Quality Conditioner Research Articles

EPO Optimized FLC Controller for PQ Improvement in Wind Integrated Power Distribution System

Nowadays, Power Quality (PQ) problems are economically affecting customers and utilities. In our work, the PQ problems are mitigated using the Unified Power Quality Conditioner (UPQC) and the proposed controller. Fuzzy Logic Controller (FLC) and Emperor Penguin Optimization algorithm (EPO) are utilized to design the proposed controller. The proposed control scheme analyses the PQ issues of harmonics, oscillatory transients, swell, and voltage sag. The optimized FLC controller-based UPQC compensates the PQ problems at a common coupling point. Using the decomposition technique, the Total Harmonic Distortion (THD) and harmonics are moderated, and the voltages sag and swell problem is minimized to improve the compensation capability. The MATLAB/SIMULINK platform is utilized to evaluate the performances of PQ issues in UPQC compensating devices. The generated, injected, and load voltages results are compared with existing controller techniques.

Performance Analysis of Distribution System with Optimal Allocation of Unified Power Quality Conditioner Considering Distribution Network Reconfiguration

Performance Analysis of Distribution System with Optimal Allocation of Unified Power Quality Conditioner Considering Distribution Network Reconfiguration

Unified Power Quality Conditioner Using Recent Optimization Technique: A Case Study in Cairo Airport, Egypt

This article offers a power quality (PQ) strategy to reduce light intensity flickers, voltage enhancements, and harmonics mitigation of the grid current in extensive networks of LED lighting at Cairo airport, Egypt. A transformerless unified power quality conditioner (TL-UPQC) with its controls is presented to address the majority of PQ issues in a network. The TL-UPQC comprises a dynamic voltage restorer (DVR) as a series compensator, which quickly maintains the load voltage when there is a voltage decrease, surge, or flickering in the network and an active power filter (APF) acts as a shunt compensator that reduces harmonic currents and injects reactive currents. The gain values of the PI controller are obtained using an extended bald eagle search (EBES) optimizer. In addition, a comparative study of three optimizers, namely, moth flame (MFO), cuckoo search (CSA), and salp swarm algorithm (SSA), is presented to test the performance of the PI controller and fast dynamic response. The results showed that the APF nearly obtained unity PF and that the harmonics produced as THD by LED light bulbs for current at the grid were abolished that becomes 3.29%. Additionally, the results verified that TL-UPQC could cancel voltage fluctuations at grid problems so that UPQC’s performance is successfully achieved to provide a flicker-free LED lighting network and this appeared clearly when used in LED lighting network at Cairo airport. MATLAB simulation has been employed to confirm the proposed TL-UPQC’s effectiveness.

Synchronized Control Strategy of UPQC to Mitigate the Sag and Swell of Voltage

AbstractThis paper demonstrates efficacy of the control strategy of Unified Power Quality Conditioner (UPQC) for improvement of three‐phase power quality. UPQC contains a couple of active power filters (APF), one is connected in series and another is shunt. Series APF belongs to the Flexible AC Transmission System (FACTS), it is a promising device for the improvement of transmission efficiency. The Voltage Source Converter (VCS) acts as the brain of series APF while the shunt APF is another part of the UPQC. This series‐connected component injects the compensating voltages that are generated by voltage source inverter (VSI). The entire system of UPQC (series and shunt APF) deals with the voltage dip and voltage swell on the consumer end of the network. Among the major advantages of the system is that this conditioner can captivate or insert true power. It can inject the voltage from 0° to 360° as per the phase angle requirement of the base voltage. It is the major reason why it can work in three different modes. This series APF acts as an active power deliverer for sag condition in the aspect of voltage. The Matlab/Simulink software is used to investigate the analysis and results.

Comparative Performance of UPQC Control System Based on PI-GWO, Fractional Order Controllers, and Reinforcement Learning Agent

In this paper, based on a benchmark on the performance of a Unified Power Quality Conditioner (UPQC), the improvement of this performance is presented comparatively by using Proportional Integrator (PI)-type controllers optimized by a Grey Wolf Optimization (GWO) computational intelligence method, fractional order (FO)-type controllers based on differential and integral fractional calculus, and a PI-type controller in tandem with a Reinforcement Learning—Twin-Delayed Deep Deterministic Policy Gradient (RL-TD3) agent. The main components of the UPQC are a series active filter and an Active Parallel Filter (APF) coupled to a common DC intermediate circuit. The active series filter provides the voltage reference for the APF, which in turn corrects both the harmonic content introduced by the load and the VDC voltage in the DC intermediate circuit. The UPQC performance is improved by using the types of controllers listed above in the APF structure. The main performance indicators of the UPQC-APF control system for the controllers listed above are: stationary error, voltage ripple, and fractal dimension (DF) of the VDC voltage in the DC intermediate circuit. Results are also presented on the improvement of both current and voltage Total harmonic distortion (THD) in the case of, respectively, a linear and nonlinear load highly polluting in terms of harmonic content. Numerical simulations performed in a MATLAB/Simulink environment demonstrate superior performance of UPQC-APF control system when using PI with RL-TD3 agent and FO-type controller compared to classical PI controllers.

Simple Control Method for Unified Power Quality based on Five-level Inverter Topologies Operating under all Voltage Disturbances

This paper proposes a simple control scheme for UPQC (Unified Power Quality Conditioner) system based on five-level NPC (Neutral Point Clamped) inverter capable to compensate all disturbances under all voltage conditions. The proposed UPQC is designed by the integration of shunt and series APFs (Active Power Filters) sharing a common dc bus capacitor. The dc voltage is maintained constant using proportional integral voltage controller. To get the reference signals for shunt and series APFs, synchronous current detection method (SCD) and instantaneous reactive power (PQ) strategies are adopted. These reference signals are derived from the control algorithm and injected in LS-SPWM (Level Shifted-Sin Pulse Width Modulation) controllers to generate the switching signals. The performance of proposed UPQC system is evaluated using MATLAB-Simulink software and SimPowerSystem Toolbox for all voltage disturbances compensation. The simulation results demonstrate the effectiveness of proposed UPQC system to improve the power quality at the common connection point of the non-linear load in steady and transient conditions operation.

Performance Analysis of Artificial Intelligence Controller for PV and Battery Connected UPQC

Nowadays, integration of the non-conventional energy sources like wind, tidal, solar etc into the grid is suggested in order to minimize the losses in the distribution network and to meet the demand. The arrival of the power electronics equipments to control the nonlinear loads has made an impact on the power quality. The unified power quality conditioner (UPQC) is a FACTS device with the back to back converters, coupled together with a DC-Link capacitor. This paper suggests an intelligent hybrid controller for the solar Photo-voltaic system and Battery storage system integrated UPQC. The proposed controller adapts both the qualities of artificial neural network and Integral sliding-mode controller. The synchronization of phases is created by self tuning filter (STF) in association with unit vector generation method (STF-UVGM) for the superior performance of UPQC during the unbalanced/ distorted supply voltages conditions. Therefore, the necessity of Phase-locked-loop, Low pass filters and High pass filters are eliminated. However, STF is used for separating the Harmonic and Fundamental components. In addition, STF-UVGM was used for generation of synchronization phases of series and shunt filters. The prime objectives of the suggested artificial neural network integral sliding mode hybrid controller (ANNISMHC) are fast action to retain the DC-Link voltage to the constant value during load/ irradiation variations, diminish the harmonics in the current waveforms, power-factor enhancement, maximum mitigation of sag, swell and disturbances in supply voltage, and compensation for the unbalanced supply voltages. The working of suggested ANNISMHC was investigated on five test cases for several combinations of loads, and balanced/unbalanced supply voltages. However, to demonstrate supremacy of the suggested ANNISMHC comparative study with the different controllers those are available in literature and also with the standard controllers like PIC, SMC, and FLC. The ANNISMHC shows an extra-ordinary performance in diminishing THD thereby improving PF and reducing voltage distortions.

Analysis of Power Quality for Distribution Networks Using Active Compensator

This paper concentrates on compensating the power quality issues which have been increased in day-to-day life due to the enormous usage of loads with power electronic control. One such solution is compensating devices like Pension Protection Fund (PPF), Active power filter (APF), hybrid power filter (HPF), etc., which are used to overcome Power Quality (PQ) issues. The proposed method used here is an active compensator called unified power quality conditioner (UPQC) which is a combination of shunt and series type active filter connected via a common DC link. The primary objective is to investigate the behavior of the compensators in the distribution networks. The performance of two configurations of UPQC, Right Shunt UPQC (RS-UPQC) and Left Shunt UPQC (LS-UPQC) are tested in the distribution networks under various load conditions by connecting them at the source side of harmonic generation using a specially constructed transformer called inductively filtered converter transformer which adopts special wiring scheme at the secondary side. PSCAD (Power Systems Computer Aided Design)/EMTDC (Electromagnetic Transients with DC Analysis) software is used to model the compensators connected to the nonlinear load. Both RS-UPQC and LS-UPQC are tested at the distribution side of the supply system with Hysteresis current controller for shunt and Sinusoidal pulse with modulation controller for series at various locations of power system network and their results are compared.

The Full Load Voltage Compensation Strategy in Capacity Configuration of燯PQC Integrated PV-BESS

Unified power quality conditioner (UPQC) with energy storage is commonly based on conventional capacity configuration strategy with power angle control. It has problems such as phase jumping before and after compensation. DC-link cannot continuously emit active power externally. Therefore, this paper presents the compensation strategy of full load voltage magnitude and phase in capacity configuration of UPQC. The topology of UPQC is integrated a series active power filter (SAPF), a shunt active power filter (PAPF) and a photovoltaic-battery energy storage system (PV-BESS). The principle of full load voltage compensation is analyzed based on the PV-BESS-UPQC topology. The magnitude constant of load voltage is maintained by controlling the appropriate shunt compensation current. Then the UPQC capacity configuration is carried out using the full load voltage compensation strategy. The compensation capacity of UPQC series and shunt units are reduced. Finally, the simulation results show that the proposed compensation strategy reduces the capacity configuration by 5.11 kVA (36.4%) compared to the conventional compensation strategy. The proposed strategy can achieve full compensation of the load voltage, which can effectively reduce the capacity allocation and improve the economy of UPQC. It also has the PV-BESS units' ability of providing active power and can stabilize the DC-link voltage.

Analysis and Power Quality Improvement in Hybrid Distributed Generation System with Utilization of Unified Power Quality Conditioner

This paper presents a comprehensive study that includes the sizing and power flow by series and parallel inverters in a distributed generation system (DGs) that integrates the system of hybrid wind photovoltaic with a unified power quality conditioner (UPQC). In addition to supplying active power to the utility grid, the system of hybrid wind photovoltaic functions as a UPQC, compensating reactive power and suppressing the harmonic load currents. Additionally, the load is supplied with harmonic-free, balanced and regulated output voltages. Since PVWind-UPQC is established on a dual compensation scheme, the series inverter works like a sinusoidal current source, while the parallel inverter works like a sinusoidal voltage source. Consequently, a smooth alteration from interconnected operating modes to island operating modes and vice versa can be achieved without load voltage transients. Since PV-Wind-UPQC inverters handle the energy generated through the hybrid wind photovoltaic system and the energy demanded through the load, the converters should be sized cautiously. A detailed study of the flow of power via the PV-Wind-UPQC is imperative to gain a complete understanding of the system operation and the proper design of the converters. Thus, curves that allow the sizing of the power converters according to the power flow via the converters are presented and discussed. Simulation results are presented to assess both steady state and dynamic performances of the grid connected hybrid system of PV-Wind-UPQC. This investigation is verified by simulating and analyzing the results with Matlab/Simulink.

Unified Power Quality Conditioners Based Different Structural Arrangements: A Comprehensive Review

Mitigating power quality issues in distribution systems is of utmost importance to both electricity consumers and suppliers as it improves the distribution system’s efficiency, reduces electricity costs, maintains continuous supply, and diminishes the requirement for frequent maintenance. Custom power devices were introduced to eliminate power quality issues like voltage sags, swells, transients, imbalances, and current harmonics arising in distribution systems. Unified power quality conditioner (UPQC) is one such frequently used custom power device that enhances the power quality of distribution systems. Various structural arrangements of UPQCs with improved performance capability were introduced within the last few decades. The main aim of this paper is to review the most frequently explored UPQC models in literature and to observe the impact of these UPQC structural configurations on their performance as well as that of the overall distribution system. Also, this study investigates the properties, applications, and control techniques used by these structural configurations of UPQCs to mitigate power quality issues.

Multi-Level Inverter Linear Predictive Phase Composition Strategy for UPQC

The power system is facing numerous issues when the distributed generation is added to the existing system. The existing power system has not been planned with flawless power quality control. These restrictions in the power transmission generation system are compensated by the use of devices such as the Static Synchronous Compensator (STATCOM), the Unified Power Quality Conditioner (UPQC) series/shunt compensators, etc. In this work, UPQC’s plan with the joint activity of photovoltaic (PV) exhibits is proposed. The proposed system is made out of series and shunt regulators and PV. A boost converter connects the DC link to the PV source, allowing it to compensate for voltage sags, swells, voltage interferences, harmonics, and reactive power issues. In this paper, the features of a seven-level Cascaded H-Bridge Multi-Level idea are applied to shunt and series active filter changeovers to reduce Total Harmonic Distortion and compensate for voltage issues. Despite its power quality capacity for common coupling, the proposed system can inject the grid’s dynamic power. During voltage interference, it can also provide a piece of delicate burden power. The simulation is carried out with the help of MATLAB/SIMULINK programming, and the results are compared to those of other conventional methods.

Design and Performance Analysis of Fuzzy Based Hybrid Controller for Grid Connected Solar-Battery Unified Power Quality Conditioner

Design and Performance Analysis of Fuzzy Based Hybrid Controller for Grid Connected Solar-Battery Unified Power Quality Conditioner

Performance Evaluation of Weighted Feedback Based UPQC under Various Power Quality Issues

Power efficiency is one of the big issues in the energy sector today. It becomes much more critical with the advent of sophisticated and complex systems, whose output is highly dependent on the efficiency of the power supply. Electronic systems are extremely vulnerable to disturbances, so industrial loads are less tolerant to power quality issues like voltage dips, voltage sags, voltage flickers, harmonics, and load unbalance, among others. For custom power applications, a variety of highly modular controllers that take advantage of newly available power electronics components are currently on the market. This paper introduces the concept of a unified power quality conditioner based on the VSC theorem, which is used to increase power quality. Capacitor banks, a series-active filter, and a shunt active filter make up the model. Negative-sequence current and harmonics are primarily compensated by series-active and shunt-active filters, while capacitor banks are used to compensate the reactive power of power frequency. This paper also includes using a weighted feedback algorithm to manage the PCC parameters as well as the UPQC performance. The proposed architecture has been put through its paces with a variety of distributed systems and fault scenarios. The entire framework was designed and analyzed with the help of MATLAB simulink and code.

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.

Holomorphic Embedded Analysis of Unified Power Quality Conditioner Compensated Power Distribution System

Unified power quality conditioner (UPQC) has been used to stabilize the voltage profile with reduced harmonics. Thus, it is important to do the impact study of UPQC over distribution system. But iterative load flow method sometime fails to converge with rise in system complexity. Thus, recursive holomorphic embedding load flow is best suited over here. This article proposes a recursive mathematical modeling of UPQC using holomorphic embedding method. This holomorphic embedded model of UPQC is based on series and shunt converters operation determined by phasor diagram. Different operating modes of UPQC are also modeled and tested. The proposed models have been tested over IEEE 13, 123 bus distribution test systems and a 19 bus practical Indian distribution grid. A rigorous comparative study with existing iterative load flow methods has been done. On analyzing the results, it shows great efficacy and reliability in terms of voltage sag mitigation and total harmonic distortion compared to conventional methods.

Performance enhancement of UPQC based on optimized GBSSA hybrid fuzzy controller with EPLL

In this research, UPQC (Unified Power Quality Conditioner) with optimized hybrid fuzzy controller based GBSSA (Gaussian Barebone Salp Swarm Algorithm) with EPLL (Enhanced Phase Locked Loop) have been proposed for power quality enhancement in power distribution networks. Using the proposed method, the difficulties in major of the power distribution system networks can be solved, related to power quality issues. GBSSA has been employed in this research, to improve solution accuracy and optimization efficiency. Given that, it is permissible to add some extra time cost to acquire a better solution, based on the Non-Free Lunch (NFL) theory, and that the time consumption of function evaluation is rather large, when addressing actual optimization problems, the extra time consumption can be overlooked to some extent. The EPLL control method improves the standard PLL, by reducing its fundamental flaw, which is the occurrence of main frequency errors, as well as double frequency errors. It controls the DC-bus voltage of unified power quality conditioners, during supply voltage and load voltage turbulences. The proposed UPQC control technique has been found to be resilient, to a variety of source and load perturbations, including unbalanced, transient distorted supply, voltage sag, unbalanced load and voltage swell. The proposed optimized GBSSA hybrid fuzzy controller with EPLL has been proven to be more effective in reducing the THD (Total Harmonic Distortion) to 3.22%. Moreover, comparative analysis with a conventional TSF-PLL has been performed with that of Takagi-Sugeno fuzzy controller and implemented using MATLAB (MATrix Laboratory).

Analysis, monitoring, and mitigation of power quality disturbances in a distributed generation system

Despite the numerous benefits of distributed generation (DG), such as reliable energy supply and environmental friendliness, there are a number of challenges associated with integrating DG with the grid. In the field of DG, the complication of power quality (PQ) is a major technical challenge. Custom power devices (CPDs) are used in the distribution system to solve complications. This study presents different PQ disturbances (PQDs), monitoring techniques, and fundamental standards. Furthermore, with the widespread literature, the study critically reviews different PQ mitigation techniques such as distribution static compensator (DSTATCOM), dynamic voltage restorer (DVR), unified power quality conditioner (UPQC), and uninterruptable power supply (UPS). The present research work is not only limited to surveying the existing techniques but also analyzing the performance of UPQC using the ANFIS controller. Overall, this study is intended to provide researchers working on improving PQ in the distribution system with a valuable resource that will aid them in enriching their research.

Optimal Design of an Artificial Intelligence Controller for Solar-Battery Integrated UPQC in Three Phase Distribution Networks

In order to minimize losses in the distribution network, integrating non-conventional energy sources such as wind, tidal, solar, and so on, into the grid has been proposed in many papers as a viable solution. Using electronic power equipment to control nonlinear loads impacts the quality of power. The unified power quality conditioner (UPQC) is a FACTS device with back-to-back converters that are coupled together with a DC-link capacitor. Conventional training algorithms used by ANNs, such as the Back Propagation and Levenberg–Marquardt algorithms, can become trapped in local optima, which motivates the use of ANNs trained by evolutionary algorithms. This work presents a hybrid controller, based on the soccer league algorithm, and trained by an artificial neural network controller (S-ANNC), for use in the shunt active power filter. This work also presents a fuzzy logic controller for use in the series active power filter of the UPQC that is associated with the solar photovoltaic system and battery storage system. The synchronization of phases is created using a self-tuning filter (STF), in association with the unit vector generation method (UVGM), for the superior performance of UPQC during unbalanced/distorted supply voltage conditions; therefore, the necessity of the phase-locked-loop, low-pass filters, and high-pass filters are totally eliminated. The STF is used for separating harmonic and fundamental components, in addition to generating the synchronization phases of series and shunt filters. The prime objective of the suggested S-ANNC is to minimize mean square error in order to achieve a fast action that will retain the DC-link voltage’s constant value during load/irradiation variations, suppress current harmonics and power–factor enhancement, mitigate sagging/swelling/disturbances in the supply voltage, and provide appropriate compensation for unbalanced supply voltages. The performance analysis of S-ANNC, using five test cases for several combinations of loads/supply voltages, demonstrates the supremacy of the suggested S-ANNC. Comparative analysis was carried out using the GA, PSO, and GWO training methods, in addition to other methods that exist in the literature. The S-ANNC showed an extra-ordinary performance in terms of diminishing total harmonic distortion (THD); thus PF was improved and voltage distortions were reduced.

HARMONICS LEVEL IMPROVEMENT OF DISTRIBUTED GENERATION INTEGRATED DISTRIBUTION SYSTEM USING UNIFIED POWER QUALITY CONDITIONER

In this paper the use of active power filter to improve voltage and current distortion caused by the presence of dispersed generation in the distribution system is investigated. The harmonics produced by photovoltaic distributed generation sources is studied and the unified power quality conditioner is introduced as a technique of minimizing these harmonics generated by the presence of distributed generation. The network is modeled and simulated in ETAP 16.0 software environment and harmonic load flow results show an increase in harmonic level when DG is introduced into the network which is subsequently reduced by the introduction of UPQC into the network.