In order to get an optimum power factor in the load compensation under distorted supply voltages, a new control strategy is proposed in this paper. In this strategy, the conductance factors for the compensated load are evaluated for the specified source current total harmonic distortion (THD) limit. The performance of this method along with perfect harmonic cancellation (PHC) and unity power factor (UPF) strategies is evaluated on a distribution system model developed using PSCAD 4.2.1. The effect of selection of control strategy in damping the harmonic resonance, which is one of the main problems for harmonic propagation in the distribution system, is verified. The simulation results are presented to evaluate the performance of these strategies in load compensation and diminishing the harmonic propagation in the distribution system. ©2009 IEEE.

Mahesh Kumar Mishra

Department of Electrical Engineering

Active power filter (APF)

Active Power Filters

Control strategies

DISTRIBUTION SYSTEM MODELS

Distribution systems

HARMONIC PROPAGATION

HARMONIC RESONANCE

Load compensation

PERFECT HARMONIC CANCELLATION

POWER DISTRIBUTION SYSTEM

Power factors

Simulation result

Source currents

Supply voltages

Total harmonic distortions

Unity power factor

ELECTRIC LOAD DISTRIBUTION

Electric power factor correction

Electric power systems

Harmonic analysis

Model structures

Optimization

Active filters

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

A new control strategy for load compensation in power distribution system

2009 International Conference on Power Systems, ICPS '09

In this paper, the theory of instantaneous symmetrical components is applied to explore various control strategies of load compensation, under different supply voltages. When the supply voltages are balanced and sinusoidal, all of these strategies converge to the same compensation characteristics. However, when the supply voltages are not balanced sinusoids, these control strategies result in different degrees of compensation in harmonics, power factor, neutral current, and compensator ratings. These control strategies are discussed in detail and a comparative study of their performance in terms of the rms value, total harmonic distortion, power factor of source currents, and compensator ratings is presented. Based on this study, it is possible to select the best strategy to meet the required load compensation characteristics for available supply voltages. A three-phase four-wire distribution system supplying an unbalanced and nonlinear load is considered for simulation study. The detailed simulation results using MATLAB are presented to support the proposed compensation strategies. © 2008 IEEE.

IEEE Transactions on Power Delivery

Control strategies for load compensation using instantaneous symmetrical component theory under different supply voltages

Current Reference Control for Shunt Active Power Filters Under Nonsinusoidal Voltage Conditions

In this paper, a novel control algorithm is proposed to compensate the unbalanced and non-linear loads in a three-phase four-wire system using active power filters. The algorithm results in balanced and sinusoidal source currents under unbalanced and distorted three-phase supply voltages. The algorithm makes use of the positive sequence extraction of the supply voltage and the theory of instantaneous symmetrical components. To illustrate the concept, a three-phase four-wire system with unbalanced and non-linear load is considered for compensation. The detailed simulation and experimental results are presented to validate the proposed method. Copyright © 2007 The Berkeley Electronic Press. All rights reserved.

International Journal of Emerging Electric Power Systems

A novel load compensation algorithm under unbalanced and distorted supply voltages

The use of power electronic circuits in a wide range of applications has resulted in distorted current waveforms in the power system. This results in nonsinusoidal voltage drops across the transformers and transmission line impedances, resulting in a nonsinusoidal voltage supply at the point of common coupling. Asymmetrical distribution of large, 1-φ loads further complicates the issue by causing imbalance in the line currents of the 3-φ system. Not only should this imbalance be compensated, other parameters, such as the current total harmonic distortion and the power factor should also be maintained as per the norms. However, the requirements of harmonic free current waveforms and good power factor, under nonsinusoidal voltage conditions, are contradictory to each other. Under these conditions, an optimum performance is the best one can achieve. This paper proposes a new scheme for balancing the currents and obtaining the best compromise between the power factor and current distortion under nonsinusoidal voltage conditions. The technique does not use p-q theory and does not require sequence transformation for power calculations, even though the current is unbalanced. All the details of this work are presented. © 2007 IEEE.

IEEE Transactions on Power Electronics

A DSP based optimal algorithm for shunt active filter under nonsinusoidal supply and unbalanced load conditions

Comparison of Control Strategies for Shunt Active Power Filters in Three-Phase Four-Wire Systems

Journal	2009 International Conference on Power Systems, ICPS '09
Open Access	No