Voltage Related Power Quality Problems Research Articles

Online harmonic extraction and synchronization algorithm based control for unified power quality conditioner for microgrid systems

This manuscript proposes an Adaptive Linear Neural Network (ADALINE) based control for the unified power quality conditioner to protect the critical loads from voltage related power quality problems and mitigate the current related power quality problems produced by nonlinear loads. Due to parallel computing feature and simple algorithm, ADALINE is utilized widely in parameter estimation. In this manuscript, unified ADALINEs based current harmonic extractor for the shunt active power filter is utilized, and an ADALINE based control technique is utilized to produce reference voltages for load voltage compensation. Due to ADALINE control, the necessity of a phase locked loop and conventional filters are omitted, therefore, enabling the system to extract the fundamental components more accurately. Besides, the ability of self-regulating transition from islanded mode to grid-connected mode has ensured that uninterrupted power supply is provided to the critical loads. The system performance is validated through simulation results utilizing MATLAB-Simulink software considering several dynamic conditions, namely unbalanced grid voltage, self-regulating transition, and grid unavailability.

Mitigation of power quality issues using UPQC

Abstract Power quality has become major concern these days due to application of power electronic devices. Conventional equipment like passive filter, segregate series and shunt filters and synchronous condenser etc. have become inadequate to mitigate different power quality problems. Since, power quality mainly concerned with voltage quality and the current quality in the system. For voltage quality, series compensator is used and for current quality, shunt compensator is used. Further, when these two power quality problems are mitigated simultaneously, the device, which is used, called unified power quality conditioner (UPQC), in power distribution system. In this paper voltage related power quality problems such as (voltage sag, voltage swell, voltage and current distortion) are discussed and UPQC controller is simulated to mitigate these problems. There are different control techniques available for UPQC. Here one of them i.e., unit vector template generation (UVTG) is used to simulate UPQC controller. The considered system efficiently regulated the DC link voltage using properly tuned PI parameters. The proposed work is also validated using experimental results.

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.

A Modified Series Voltage Controller for Power Conditioning

A compensation method for mitigation of voltage related power quality problems with the use of Series Voltage Regulator well known as Series Active Power Filter or Dynamic Voltage Restorer is presented in this paper. The classical control algorithm used for series voltage regulator based on the Park transformation is modified by introducing a Selective Harmonic Filter at detection stage of source current in order to compensate harmonic frequencies which mainly affect power frequency voltages. The significant outcomes are sag restoration, reduction of total harmonic distortion and removal of transients from the supply voltage. Thus it makes possible to improve performance of series voltage controller as power conditioner to mitigate various voltage related power quality issues. The proposed approach is cost effective because same series voltage controller can be used as power conditioner by modifying control strategy used. Also it is possible to eliminate use of PI controller from control circuitry. The usefulness and robustness of the proposed mitigation strategy is confirmed by simulation studies. The presented series voltage controller has ability to mitigate the power quality issues arising due to charging of electric vehicles.

A Novel Multiobjective Control of DVR to Enhance Power Quality of Sensitive Load.

The Dynamic Voltage Restorer (DVR) is one of the fast, flexible, and cost effective solutions available in compensating the voltage-related power quality problems in power distribution systems. In this paper is discussed how power quality enhancement of sensitive load is achieved by applying three versions of Autonomous Group Particle Swarm Optimization like AGPSO1, AGPSO2, and AGPSO3 for tuning the Proportional-Integral DVR controller under balanced and nonlinear load conditions. A novel multiobjective function is formulated to express the control performance of the system, which is quantified using three power quality indices such as Total Harmonic Distortion (THD), voltage sag index, and RMS voltage variation. The obtained results are compared with the Proportional-Integral (PI) controller tuned by Ziegler-Nichols (ZN) method and also by Simple Particle Swarm Optimization based PI controlled DVR. The proposed methodology has improved the performance in terms of the considered power quality indices and the simulation has been carried out in MATLAB/Simulink environment.

Fast Envelope Estimation Technique for Monitoring Voltage Fluctuations

Voltage quality problems such as voltage sag, swell, flicker, undervoltage, and overvoltage have been of great concern for both utilities and customers over the last decade. In this paper, a new approach based on the <TEX>$H_{\infty}$</TEX> algorithm to monitor voltage disturbances is presented. The key idea of this approach is to estimate the amplitude of the fundamental component of distorted and noisy voltage waveform instantaneously, and then the information can be extracted from the estimated envelope to identify and classify different voltage related power quality problems. The <TEX>$H_{\infty}$</TEX> algorithm is characterized by a fast tracking, unlike that of existing techniques. The <TEX>$H_{\infty}$</TEX> algorithm outperforms the Kalman Filter (KF) by its fast convergence and robust tracking performance against non-Gaussian noise. The paper investigates the effects of various types of noise on the performance of the <TEX>$H_{\infty}$</TEX> algorithm. Digital simulation results confirm the validity and accuracy of the proposed method. The proposed <TEX>$H_{\infty}$</TEX> algorithm is examined by tracking the flicker produced by a resistance welder simulated in the PSCAD/EMTDC package.