Comparison of different optimization criteria for optimal sizing of hybrid active power filters parameters

Praise Worthy Prize granted a permission for Brunel University London to archive this article in BURA.Harmonic distortion in power systems has increased considerably due to the increasing use of nonlinear loads in industrial firms and elsewhere. This distortion can give rise to overheating in all sectors of the power system, leading to reduced efficiency, reliability, operational life and sometimes failure. This article seeks to propose a new methodology for the optimal sizing of hybrid active power filter (HPF) parameters in order to overcome the difficulties in hybrid power filters design when estimating the preliminary feasible values of the parameters. Sequential Quadratic Programming based on FORTRAN subroutines is used to find out the planned filter size in two different optimization criteria depending on design concerns. The first criterion is to minimize the total voltage harmonic distortion. The second one is to maximize the load power factor, while taking into account compliance with IEEE standard 519-1992 limits for the total voltage harmonic distortion and the power factor.The effectiveness of the proposed filter is discussed using four exemplary case

LC compensators based on transmission loss minimization for nonlinear loads

This material is posted here with permission of the IEEE. Such permission of the IEEE does not in any way imply IEEE endorsement of any of Brunel University's products or services. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to [email protected]. Copyright @ 2004 IEEEThis paper presents a method employing the penalty function search algorithm to determine the LC compensator value for the optimal power factor correction in nonsinusoidal systems. The objective of the proposed method is to minimize the transmission loss while the power factor and efficiency are taken as constraints and utilized in order to solve the multiobjective optimization problem by transforming it into a single objective one. Examples show that the load nonlinearity can have a significant impact on optimal compensator sizes

Practical considerations regarding power factor for nonlinear loads

This material is posted here with permission of the IEEE. Such permission of the IEEE does not in any way imply IEEE endorsement of any of Brunel University's products or services. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to [email protected]. Copyright @ 2004 IEEEThe choice of LC compensator may be constrained by the availability of manufacturers units. To account for this, the capacitor values are chosen from among standard values and for each value the transmission losses is minimized, or power factor is maximized, or transmission efficiency is maximized. The global minimum or maximum is obtained by scanning all local minims or maxims. The performance of the obtained compensator is discussed by means of numerical examples

Optimal sizing of C-type passive filters under non-sinusoidal conditions

In the literature, much attention has been focused on power system harmonics. One of its important effects is degradation of the load power factor. In this article, a C-type filter is used for reducing harmonic distortion, improving system performance, and compensating reactive power in order to improve the load power factor while taking into account economic considerations. Optimal sizing of the C-type filter parameters based on maximization of the load power factor as an objective function is determined. The total installation cost of the C-type filter and that of the conventional shunt (single-tuned) passive filter are comparatively evaluated. Background voltage and load current harmonics are taken into account. Recommendations defined in IEEE standards 519-1992 and 18-2002 are taken as the main constraints in this study. The presented design is tested using four numerical cases taken from previous publications, and the proposed filter results are compared with those of other published techniques. The results validate that the performance of the C-type passive filter as a low-pass filter is acceptable, especially in the case of lower short-circuit capacity systems. The C-type filter may achieve the same power factor with a lower total installation cost than a single-tuned passive filter

Harmonics mitigation based on the minimization of non-linearity current in a power system

Harmonic issues in power systems are becoming an important topic for industrial customers and power suppliers alike due to their adverse effects in both consumer appliances as well as for utility suppliers. Consumers should seek to reduce harmonic pollution, regardless of voltage or current distortion already present in the network. This article suggests a new method for suppressing distortions by using the non-linearity current index (NLCI) to determine the shunt single-tuned passive filter (STPF) compensator value in non-sinusoidal power systems, with the objective of maintaining the power factor within desired limits. The objective of the proposed method is to minimize the nonlinear current of customer’s loads in the power system at the point of common coupling (PCC). Moreover, the proposed design takes into consideration other practical constraints for the total voltage and individual harmonic distortion limits, ensuring compliance with (Institute of Electrical and Electronics Engineers) IEEE 519-2014 guidelines, maintaining distortions at an acceptable level while also abiding by the capacitor loading constraints established in IEEE 18-2012. The performance of the optimally designed compensator is assessed using well documented IEEE standards based on numerical examples of nonlinear loads taken from previous publications

Modelling and Simulation of Parallel/Series Hybrid Filter to Achieve Active Resonance Damping

Hybrid power filters is widely known and acknowledged in the field of power quality improvement especially in mitigating harmonics and compensating the reactive power. Since it is the combination of the passive and active filter in a circuit, it is not only simple, but also found to be cost-effective. It has been tested in various scale of power distribution network and proven to be working efficiently. The quality of the power transferred to the load in improved by mitigating the harmonics and damping out the resonances present. This paper is discussing the most suitable and applicable type of hybrid filter for both of the case studies ; the small distribution network of source 630 kVA 400V and the wind farm with capacity of 2MW for each of the 20 wind turbines. Classified references presented in this paper would serve for a quick reference

Survey of harmonic reduction techniques applicable as ancillary service of dispersed energy generators (DG)

Fundamental ways to reduce harmonics are: reduction of resonances, damping of harmonics and compensation of harmonics. Harmonic compensation is difficult to achieve, but can reduce harmonics to zero. However, if a rest distortion is allowed, harmonic compensation could be replaced for only harmonic damping. Harmonic damping by a resistive harmonic behavior of a power electronic converter of a dispersed generator (DG), is an attractive way of harmonic reduction. This damping can have effect on a total range of harmonics and cannot result in instabilities in the power system. The damping can be provided as an ancillary service of a power electronic converter in general. The resistance is virtual, therefore the energy involved is limited to losses in the converter. The effort to be taken, to implement this kind of ancillary service, is an extension in the control system of the converter, therefore costs can be kept minimal. There is however a contradiction with the needed measure for background harmonics, therefore harmonic reduction by damping must be limited to avoid wrong compensation for background harmonics, resulting in excessive currents through the distribution transformer, cables and/or lines. A combination with a series active filter on substation level, and harmonic damping dispersed over the distribution network, can avoid the wrong compensation for background harmonics, and be therefore an optimal solution for harmonic mitigation

Simulation study on the material stress distribution respect to different angle of ECAP

This research study focused on the influence of channel angle towards stress distribution of material aluminium alloy 5083. The size of the grain is related to the mechanical properties of material. Equal channel angular pressing (ECAP) is a process to produce ultrafine-grained, a method for deforming materials in such a way that a strong mechanical properties material is generated while the dimensions of the work piece remained unchanged. Die channel angle is one of the parameter in ECAP. To design a die channel angle, it is important to understand the effect of it with material stress distribution. A simulation using ABAQUS CAE has been carried out at channel angle 90°, 110°, and 130° to understand the effect die channel angle toward stress distribution. The die channel angle is designed differently to see the effect of stress distribution when the work piece passed through the channel angle. The grain structure was assessed at the point where the die's channels angle intersected. The analysis obtained in this study shows the result of the influence of die channel angle towards stress distribution. It is understood that the channel angle affects the mechanical behavior as the angle decrease from 110° to 90°, the higher the stress occur at the channel angle

Review on power quality solution technology

This paper presents a comprehensive study of various possible solutions for power quality improvement in common applications and supply system. This includes improved power quality converters (IPQC), multi-pulse converters, active compensation, passive compensation and their hybrid configurations. Various configurations and topologies of custom power devices such as DSTATCOM (Distribution Static Compensator), DVR (Dynamic Voltage Restorer) and UPQC (Unified Power Quality Compensator) are also described in detail. Main applications of these devices are for reactive power compensation, harmonic elimination, voltage sag/swell mitigation, voltage regulation, load balancing, neutral current reduction etc. Many such cases of power quality problems have been taken up and suitable solutions have been identified for those cases. As an example, a model of DSTATCOM is developed and its performance is presented for a distribution system feeding nonlinear loads

A new method for power quality improvement

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.A new control method for active power filters in conjunction with a passive filter circuit are presented and analysed in this thesis. A new technique for load modelling is introduced in order to enable the design of compensators to improve the power factor and to reduce harmonic levels in electrical power systems. The principles of analysis, design, operation and control of the new circuit equipped with IGBTs are presented. This enables the compensation of rapidly changing loads and reactive power. A special circuit equipped with IGBTs is able to compensate for the reactive power and harmonic currents of different orders. The important aspect of the present work is based on the compensator control circuit for power factor correction and harmonic elimination, and its application. This new configuration improves the rating of the active power filter, reducing power losses in the switches compared to existing and newly developed active filters. Furthermore, it is very stable in operation and much faster by a factor of 20. The thesis also presents a detailed mathematical modelling of the proposed system with frequency and time domain equations. The frequency response of the proposed system is also discussed. This new proposal has been checked using a dedicated software simulation program, which was specifically developed for this purpose. An experimental set-up has been designed and implemented in order to apply the new method using IGBTs as well as some other devices. This thesis also presents a critical literature survey, which provides a critical overview of previous work relevant to the power quality improvement reactive power compensation and active filtering