Power Quality Improvement Devices Research Articles

Multi-objective model predictive control for microgrid applications

Integration of microgrids may introduce significant power quality challenges to the power distribution networks that may necessitate additional enforcement such as installing new Power Quality Improvement Devices (PQID), which is costly and not always possible option. This paper proposes a control approach that enables the existing power electronics devices within the microgrid to perform multiple functions to address the resultant power quality problems. The proposed method introduces flexibility in harmonic and fundamental power sharing and controlling switching frequency through an improved cost function. Grid connected operation-mode, harmonic compensation capabilities as well as improved dynamic response of controller to fast reference changes have been studied and experimentally verified on a microgrid prototype. Finally, the experimental results of the proposed control method are compared with the results from most recent relevant research activities in the field, evidencing its superiority as compared to the existing control methods presented in the literature.

Adaptive Interval Type II Fuzzy Logic Controller with Interface Inductor Bank Pulse Generator Based Three-Phase Four-Wire DSTATCOM Device for Power Quality Improvement

It goes without saying that the electrical distribution system is facing many power-quality issues these days. The main cause of these issues is the wide spread of nonlinear load integrated with the electrical distribution system. Moreover, the DSTATCOM device with interface inductor has different control algorithms. These encompass proportional integral controller, Interval type I fuzzy logic and interval type II fuzzy logic along used for improving the power quality issues. Before integration with the electrical distribution grid, these controllers need the tune processing. The combination of DSTATCOM with the load, which is different from the tuned one, and the wrong selection of the interface inductor leads to the failure of DSTATCOM device in the mitigation of source current harmonics. This study suggests that the use of adaptive interval type II fuzzy logic with the interface bank pulse generator based DSTATCOM device with self-tunning process and self-selection of the interface inductor would be suitable for all load types integrated into the distribution system within the rated power of DSTATCOM device. The adaptive interval type II fuzzy logic with the interface bank pulse generator based DSTATCOM device mitigates the source current harmonics and gives fast DC capacitor bus voltage response. Employing the suggested control algorithm based DSATCOM device makes the DC capacitor voltage signal settling time at almost 50 ms and total harmonic distortion of the source current at almost 4% for all cases of the load connected with the distribution system within the rated power of DSTATCOM device.

Parameter optimization of PV integrated Shunt Active power filter with Taguchi SNR

Abstract In this article, a better optimization method known as the Taguchi method is implemented for optimizing the designing parameters of PV integrated Shunt Active power filter (SAPF). The effect of these parameters on the performance of SAPF is also studied with the help of this method. This paper also signifies the benefits of using the Taguchi method for optimization over the existing particle swarm optimization (PSO) algorithm. SAPF is a very popular device for power quality improvement through harmonics compensation. In non-conventional energy sources, solar is most widely used dues to its cost-effectiveness over other sources. Hence, PV integrated SAPF is considered for study for this article. Incremental conductance (IncCond) based maximum power point tracking (MPPT) technique is used to extract the maximum power from PV panel. Performance of this PV Integrated SAPF depends on many factors like reference current generation techniques, switching pulse generation technique and selection of SAPF designing parameters, etc. To get the optimum performance from SAPF, designing parameters like gains of PI-controller, coupling impedance, and dc-link capacitor need to be optimized. PV integrated SAPF is modeled and simulated in Matlab/Simulink. SAPF parameters are optimized by using both the proposed Taguchi method and the existing PSO algorithm and their results are analyzed. Simulation results are also verified using a laboratory-developed experimental setup.

Analysis of Traditional and Alternative Methods for Solving Voltage Problems in Low Voltage Grids: An Estonian Case Study

Smart Cities can benefit from existing municipal low voltage (LV) distribution grids by supporting public services with permanent power supply and providing grid connection points to distributed generators (DG). The increased integration of DGs and inverter based non-linear loads increases voltage quality issues, thus the cost-efficient assurance of voltage quality in LV grids with long radial lines is of increasing importance for the operators of municipal electricity distribution systems. Conventional methods for mitigating voltage quality issues (e.g., power line renovation) might not be optimal solutions either technologically or economically. Existing studies do not address all relevant issues related to the assurance of required voltage quality in such LV grids. This paper provides an overview of the applicability and rationality of traditional as well as alternative methods to solve voltage problems in LV grids. The authors use DIgSILENT PowerFactory software to simulate the performance of voltage stabilisers under different conditions. The authors propose a robust method for the classification of LV feeders and provide recommendations on how to resolve voltage quality problems, with the help of different power quality improvement devices, where the traditional methods of upgrading to medium voltage and grid reinforcement are economically infeasible. Based on our results, recommendations for mitigating voltage quality problems in LV distribution grids with radial lines of different lengths are given.

Artificial Neural Network Active Power Filter with Immunity in Distributed Generation

With an electrical grid shifting toward Distributed Generation (DG), the emerging use of renewable energy resources is continuously creating challenges to maintain an acceptable electrical power quality thought-out the grid; Therefore, in an energy market where loads are becoming more and more sensitive in a distributed generation filled with polluting nonlinear loads, power quality improvement devices such Active Power Filters (APFs) have to evolve to meet the new standards, since theirs conventional control strategies can't properly operate when multiple power quality problems happens at once, even the one using AI based control as it will be proven in this paper. In this paper a neural network based Active Power Filter will be tested in a DG environment where both current and voltage harmonics, along with fast frequency variation occurs, we will see how the PLL can downgrade its performances enormously under such hostile conditions, We propose to solve this problem by replacing the conventional PLL with a nonlinear least square (NLS) frequency estimator, this novel NLS-ADALINE SAPF is immune in high DG penetration environment, as it will be tested and validated experimentally on an Opal-RT OP5600 FPGA based real-time simulator.

Active power quality management in smart microgrids

In this manuscript, a new concept of active power quality management (APQM) is presented. In which, instead of solely controlling the nodal power quality in a power system, the power quality is seen as a network-level issue and a high-level management method to deal with this issue in distribution networks is presented. Analogous to how active network management enables increased levels of hosting capacity for interconnection of distributed energy resources (DERs) by managing thermal and voltage constraints, APQM maps consumer requirements and technical and regulatory standards to specific areas and actively manages operational power quality limits, rather than relying on interconnection planning screens. APQM includes re-structuring of distribution network and integration of renewable energy sources (RESs) to increase the supply reliability for critical loads, smart management, and optimised installation of power quality improvement devices (PQIDs) to enhance the distributed power quality improvement, adding ancillary functionalities to installed DER power electronic converters to increase the cost-effectiveness of DERs. Last but not the least, in this study, coordinated control of the PQIDs and high-penetration non-linear loads will also be discussed.

UPQC: A Custom Power Device for Power Quality Improvement

Power Quality (PQ) has increased concern amongst utilities at all levels of usage. The development of power electronic devices has made a notable impact on the quality of electric power supply. The operation of nonlinear loads generates harmonics and thus, deteriorates the quality of distribution system. In such cases both utilities and end users of electric power are gradually more concerned about the quality of power. This suggests that few course of action has to be taken so that the power quality can be improved. In this paper the main focus is on UPQC, which is a combination of series and shunt active power filters. The series APF alleviates voltage based distortions, while shunt APF mitigates current based distortions. UPQC alleviates the voltage and current based distortions concurrently as well as independently. UPQC improves power quality by compensating both harmonics and load current which thereby makes source current and load voltage sinusoidal at the required voltage level.The modelling of series APF, shunt APF and the UPQC has been carried out using MATLAB/Simulink.

Comparison of DSTATCOM Performance for Voltage Sag Alleviation

<p><em>This paper describes the comparative analysis of three different control techniques of distributed flexible AC transmission system (DFACTS) controller called as distributed static synchronous compensator (DSTATCOM), </em><em>aimed at power quality (PQ) enhancement in terms of voltage sag mitigation in a three-phase four-wire (3p4w) distribution system. A DSTATCOM is one of the major power quality improvement devices which consist of a DC energy source, a voltage source inverter (VSI), a filter, a coupling transformer and the control system. The control strategy based on synchronous reference frame (SRF) theory, instantaneous active and reactive current (IARC) theory and propositional-integral (PI) controller has been used for reference current generation of voltage source inverter (VSI) based DSTATCOM. The SRF, IARC and PI control based DSTATCOM is validated through dynamic simulation in a MATLAB\SIMULINK environment under linear as well as nonlinear loads.</em></p>

A Single-Phase Active Device for Power Quality Improvement of Electrified Transportation

A transformerless hybrid series active filter is proposed to enhance the power quality in single-phase systems with critical loads. This paper assists the energy management and power quality issues related to electric transportation and focuses on improving electric vehicle load connection to the grid. The control strategy is designed to prevent current harmonic distortions of nonlinear loads to flow into the utility and corrects the power factor of this later. While protecting sensitive loads from voltage disturbances, sags, and swells initiated by the power system, ridded of the series transformer, the configuration is advantageous for an industrial implementation. This polyvalent hybrid topology allowing the harmonic isolation and compensation of voltage distortions could absorb or inject the auxiliary power to the grid. Aside from practical analysis, this paper also investigates on the influence of gains and delays in the real-time controller stability. The simulations and experimental results presented in this paper were carried out on a 2-kVA laboratory prototype demonstrating the effectiveness of the proposed topology.

Technology assessment for power quality mitigation devices – Micro-DVR case study

This work presents a case study on technology assessment for power quality improvement devices. A system compatibility test protocol for power quality mitigation devices was developed in order to evaluate the functionality of three-phase voltage restoration devices. In order to validate this test protocol, the micro-DVR, a reduced power development platform for DVR (dynamic voltage restorer) devices, was tested and the results are discussed based on voltage disturbances standards.