The existence of non-standard currents, frequencies and voltages enhances the Power Quality (PQ) problems. Power consumed by the consumers and losses occurred in power system are deciding factors for the utility to determine the performance of the power system in terms of Power Quality. These Power Quality problems lead to failure of end user equipments as well as creates disturbances in power distribution network, thereby deteriorates residual life assessment of major equipments used in substation. The PQ problems can be characterized as voltage surges, sags, swells, harmonic distortions, etc. There are many reasons for the determination of Power Quality. The loads used by the consumers of electricity abnormally leads to deprove the Power Quality. Low power factor loads are taken care of by the utilities in the form of financial penalty. However, occurrence of harmonics, voltage swells and sags in the system is the most powerful reason behind degradation of Power Quality. To mitigate these issues, use of Custom Power Devices (CPD) in the distribution network is the most significant solution. Paper presents the design of the CPD like Dynamic Voltage Restorer (DVR) using two control strategies i.e. PI Controller and Fuzzy Logic Controller (FLC). MATLAB/SIMULINK is used to analyze the effectiveness of these control strategies.

/pdf/power-quality-problems-mitigation-using-dynamic-voltage-7d5ksoyhkr.pdf

Power quality problems mitigation using dynamic voltage restorer (DVR) with pi controller and fuzzy logic controller

In today’s scenario, the power quality issues like voltage sag and swell are major concerns in power systems. On the distribution, side to overcome this issue a custom power device DVR(Dynamic Voltage Restorer) is proven to be a more effective solution that is lower in cost, smaller in size, and offers a faster dynamic response for the protection of sensitive load. DVR is a series compensating device which operates as a voltage booster. The application of DVR is entitled to be a flawless compensating device for the compensation of voltage sag and swell. This paper presents the modeling and simulation using various controller topologies like PI controller based on synchronous reference frame algorithm, fuzzy controller, and interval type 2 fuzzy controller. The results are then verified using a Matlab-Simulink environment.

/pdf/comparative-analysis-of-pi-controller-fuzzy-controller-and-447ci4jli4.pdf

Comparative Analysis of PI controller, Fuzzy controller and Interval Type-2 Fuzzy based Performance of Dynamic Voltage Restorer for Compensation of Voltage Sag and Swell

The dynamic voltage restorer (DVR) is a fast and efficient solution to voltage sag problems. This paper proposes a new configuration of DVR which is based on the parallel diode-clamped modular multilevel converter (parallel-DCM2C). In the parallel-DCM2C topology the capacitor voltages distributed in the sub-modules (SMs) can be balanced automatically without any balancing control algorithms. Additionally no SM capacitor voltage sensors are required. In this paper the compensation strategy is also developed with the new configuration. Experimental results verified the voltage self-balancing performance and compensation functionality of this novel DVR.

A novel DVR based on parallel-connected diode-clamped modular multilevel converters

With the advancement of technology, the dependency on the electrical energy has been increased greatly. Computer and telecommunication networks, railway network banking, post offices, and life support systems are a few applications that cannot function without electricity. At the same time, these applications demand qualitative energy. However, the quality of power supplied is affected by various internal and external factors of the power system. Harmonics, voltage, and frequency variations deteriorate the performance of the system. Voltage sag/dip is the most frequent problem and there are many methods to overcome this problem. The use of FACT devices is an efficient one. This chapter discusses an overview of the FACT device known as dynamic voltage restorer (DVR) in mitigating voltage sag. The strategy to control this device is also presented. The proposed control strategies are simulated in MATLAB SIMULINK environment and analyzed. The method is utilized and discussed briefly.

Power Quality Improvement in Distribution System Using Dynamic Voltage Restorer

The quality of electrical power is an important contributing factor to the development of any country. Power quality is highly newsworthy issue as it has attained considerable attention in the last few decades due to large penetration of power electronic based loads or microprocessor based controlled loads. In order to avoid the unexpected disruptions and damage in the power system it becomes necessary to overcome power quality issues and to have reliable power performance. Mitigation of power quality event helps the power system to overcome the power quality issues to a great extent. To enhance the quality of power and to reduce the issues related to it, mitigation of power quality events is preferred. Mitigation of power quality event not only provides the control over the power related problems but also maintains it. Therefore, this paperwork proposes dynamic voltage restorer (DVR) as a mitigation tool for the most common power quality problem of voltage sag. Dynamic voltage restorer (DVR) shows the effective result in sag mitigation. The DVR used in this paper uses the feed forward linear control method for the voltage sag mitigation. The voltage injection method used is the pre -sag method. This work has been performed using MATLAB Simulink. Before and after sag mitigation results are provided.

https://www.ijirt.org/master/publishedpaper/IJIRT150196_PAPER.pdf

DVR Based Mitigation of Voltage Sag

Power quality is the major concern in today's electrical power system. Especially, power quality problems are continuously observed in distributed electrical power system. Mainly the voltage quality is the major aspect in distributed electrical power system. Voltage sags and voltage swells are the main parameters on which the improvement is needed. Voltage quality can be sufficiently improved in distributed electrical power systems by using some custom power devices such as dynamic voltage restorer. The Dynamic Voltage Restorer (DVR) is fast, flexible and efficient solution to voltage sag and voltage swell problems. The DVR is a power electronic based device that provides three-phase controllable voltage output, whose voltage vector-magnitude and angle-adds to the supply voltage during sag event, to restore the load voltage to pre-sag conditions. And when voltage swell occurs DVR injects 180° out of phase voltage into the line. The DVR is designed for protecting the whole plant with loads in the range of some MVA. The DVR can restore the load voltage within few milliseconds.

Chirag H. Rovai

Papers

An overview of various control techniques of DVR