Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 17 of 17

Full-Text Articles in Physical Sciences and Mathematics

Establishment Of Typical Harmonic Voltage Levels In Radial Distribution Systems, D. A. Robinson, V. J. Gosbell, B. S. Perera, D. J. Mannix Dec 2012

Establishment Of Typical Harmonic Voltage Levels In Radial Distribution Systems, D. A. Robinson, V. J. Gosbell, B. S. Perera, D. J. Mannix

Dr Duane Robinson

This paper reports on a simple method to identify problem areas with relation to harmonic distortion within radial distribution systems at the planning stage. The purpose of the work is to produce a simple method of establishing harmonic distortion levels throughout a study distribution system when only limited system data and load information is available. The preliminary work presented in this paper is aimed at establishing useful planning guidelines for utilities to help with the analysis of harmonics in medium voltage (MV) distribution systems during the design phase. Harmonic analysis during the design of a distribution system is seen as …


Assessing The Impact Of Increased Air Conditioner Load On Power Quality In Australia, Lianne Mollier, D A. Robinson, Sarath Perera, Victor J. Gosbell, Frank Bucca Dec 2012

Assessing The Impact Of Increased Air Conditioner Load On Power Quality In Australia, Lianne Mollier, D A. Robinson, Sarath Perera, Victor J. Gosbell, Frank Bucca

Dr Duane Robinson

Measurements of performance of existing technology air conditioner systems with regards to their impact on power quality in LV distribution systems are presented. Three types of split-phase air conditioners are studied including direct on line starting, soft starter and inverter fed units. Results of testing and subsequent calculations illustrate that the direct on line and soft starter units do not meet compliance requirements of the relevant standard, and as penetration of air conditioners increases, voltage fluctuations may become a significant problem in some LV distribution systems in Australia.


Flicker Transfer In Radial Power Systems, Sankika Tennakoon, Lakshal Perera, D A. Robinson, Sarath Perera Dec 2012

Flicker Transfer In Radial Power Systems, Sankika Tennakoon, Lakshal Perera, D A. Robinson, Sarath Perera

Dr Duane Robinson

Loads which exhibit continuous and rapid variations in their current can cause voltage fluctuations that are often referred to as flicker. One good example for such loads is arc furnaces which are usually fed by dedicated feeders from the high voltage busbars in transmission systems. The flicker generated from such loads will propagate to the upstream HV point of common coupling (PCC), and from there to the downstream through the transmission and sub transmission systems. This paper demonstrates how the generated flicker is propagated from the HV PCC to the downstream in radial networks exhibiting different levels of attenuation depending …


Issues Affecting Power Engineering Undergraduate Education In Australia, D A. Robinson, Victor J. Gosbell Dec 2012

Issues Affecting Power Engineering Undergraduate Education In Australia, D A. Robinson, Victor J. Gosbell

Dr Duane Robinson

Recent changes to the electric power industry through deregulation and restructuring have had a considerable effect on power engineering education internationally. A number of Australian universities have also noticed a decline in the number of students interested in power engineering subjects, leading to the fewer graduates with power engineering knowledge. With a reduction in graduates and a perception of an aging workforce a shortage of suitably qualified power engineers for industry may be imminent. This paper provides discussion on the current status of university power engineering education within Australia and includes results from a recent Australia-wide survey of the university …


Allocating Harmonic Emission To Mv Customers In Long Feeder Systems, D A. Robinson, Victor J. Gosbell Dec 2012

Allocating Harmonic Emission To Mv Customers In Long Feeder Systems, D A. Robinson, Victor J. Gosbell

Dr Duane Robinson

Previous work has attempted to find satisfactory methods for the allocation of harmonic current emission MV subsystems containing long feeders. It has been proposed that best use of the network's harmonic absorption capacity is made if the allocated current varies with the inverse square root of the harmonic impedance at the point of connection. It has been shown that an exact solution following this principle requires an impracticably large amount of data. Here it is assumed that each feeder supplied from a given substation has its load distributed uniformly and continuously along it, giving equations requiring only a modest amount …


The Application Of Iec 61000-3-6 To Mv Systems In Australia, Victor J. Gosbell, D A. Robinson, Sarath Perera, Alex Baitch Dec 2012

The Application Of Iec 61000-3-6 To Mv Systems In Australia, Victor J. Gosbell, D A. Robinson, Sarath Perera, Alex Baitch

Dr Duane Robinson

IEC 61000-3-6 [1] comprises a number of stages and tests to determine harmonic emission allowances for customers connected to MV or HV networks. Of particular importance is the section concerning loads distributed along a feeder, each having a different fault level. Although a common situation, the treatment given in the IEC standard is poorly described, being largely illustrated by one atypical example. This allows simplifying assumptions to be made which are invalid in practical cases. This paper outlines a more general approach that is relatively easy to apply.


A Transient Index For Reporting Power Quality Surveys, Victor J. Gosbell, Sarath Perera, D A. Robinson, Chandana Herath Dec 2012

A Transient Index For Reporting Power Quality Surveys, Victor J. Gosbell, Sarath Perera, D A. Robinson, Chandana Herath

Dr Duane Robinson

Impulsive transients are often blamed for the destruction of customer appliances. Advances in Power Quality (PQ) monitors will soon make it feasible to incorporate impulsive transients into routine power quality surveys. This paper considers how the transient events captured over a period at many sites may be reported in a simple but useful manner. The paper first summarizes a recent publication by some of the authors, which attempt to give a complete framework for the analysis of utility PQ data. This framework provides a basis for evaluating existing transient characterization practices as well as for the proposed new transient index …


Clustering, Classification And Explanatory Rules From Harmonic Monitoring Data, Ali Asheibi, David A. Stirling, Danny Sutanto, D A. Robinson Dec 2012

Clustering, Classification And Explanatory Rules From Harmonic Monitoring Data, Ali Asheibi, David A. Stirling, Danny Sutanto, D A. Robinson

Dr Duane Robinson

A method based on the successful AutoClass (Cheeseman & Stutz, 1996) and the Snob research programs (Wallace & Dowe, 1994); (Baxter & Wallace, 1996) has been chosen for our research work on harmonic classification. The method utilizes mixture models (McLachlan, 1992) as a representation of the formulated clusters. This research is principally based on the formation of such mixture models (typically based on Gaussian distributions) through a Minimum Message Length (MML) encoding scheme (Wallace & Boulton, 1968). During the formation of such mixture models the various derivative tools (algorithms) allow for the automated selection of the number of clusters and …


The Estimation Of Continuous Pq Disturbance Levels In Distribution Systems, Victor J. Gosbell, D A. Robinson Dec 2012

The Estimation Of Continuous Pq Disturbance Levels In Distribution Systems, Victor J. Gosbell, D A. Robinson

Dr Duane Robinson

A simple method is given for estimating the continuous PQ disturbance level at a site. It is based on determining a "Voltage Distortion Increment" (VDI) for each segment of the network and then adding the VDIs from a given site back to an upstream site where levels are taken to be zero. The VDI is conveniently expressible in the form of S(MVA) times length (km), where "length" correspond to the physical length in the case of MV overhead lines and an equivalent length for other components. The method is verified by a comparison with field survey data. The voltage distortion …


Power Quality Data Analysis Using Unsupervised Data Mining, Ali Asheibi, David A. Stirling, Sarath Perera, D A. Robinson Dec 2012

Power Quality Data Analysis Using Unsupervised Data Mining, Ali Asheibi, David A. Stirling, Sarath Perera, D A. Robinson

Dr Duane Robinson

The rapid increase in the size of databases required to store power quality monitoring data has demanded new techniques for analysing and understanding the data. One suggested technique to assist in analysis is data mining. Data mining is a process that uses a variety of data analysis tools to identify hidden patterns and relationships within large samples of data. This paper presents several data mining tools and techniques that are applicable to power quality data analysis to enable efficient reporting of disturbance indices and identify network problems through pattern recognition. This paper also presents results of data mining techniques applied …


Harmonic Planning Levels For Australian Distribution Systems, Victor J. Gosbell, Victor W. Smith, D A. Robinson, W Miller Dec 2012

Harmonic Planning Levels For Australian Distribution Systems, Victor J. Gosbell, Victor W. Smith, D A. Robinson, W Miller

Dr Duane Robinson

A modelling technique is developed for determining the harmonic voltage distribution across a distribution system when there is an equitable distribution of harmonic emission. The harmonic voltages at the 132kV and 415V levels are fixed to values based on IEC Compatibility and Planning Levels and the intermediate voltages determined. Studies are made of six systems, typical of Australian distribution practice, to examine the effect of choice of voltage level and system parameters over the harmonic range of 2-40. Based on the study, harmonic Planning Levels are recommended for application to Australian distribution systems.


Sag Testing Of Dairy Farm Milking Equipment, V. J. Gosbell, V. Smith, D. A. Robinson, B. S. Perera Dec 2012

Sag Testing Of Dairy Farm Milking Equipment, V. J. Gosbell, V. Smith, D. A. Robinson, B. S. Perera

Dr Duane Robinson

Sags are widely reported as being one of the worst power quality problems and are particularly common in rural areas. Automated milking equipment on dairy farms are thus very susceptible to malfunction by sags. In assessing the relative cost/benefits of sag mitigation in the dairy or the supply network it is important to know the dairy equipment immunity level. It is shown how a harmonic generator can be used to determine this information. Testing revealed that the motor contactor was a critical component as it was unable to ride through a 40% sag longer than about 0.5 seconds. The milking …


Response Of Mains Connected Induction Motors To Low Frequency Voltage Fluctuations From A Flicker Perspective, Sankika Tennakoon, Sarath Perera, D A. Robinson Dec 2012

Response Of Mains Connected Induction Motors To Low Frequency Voltage Fluctuations From A Flicker Perspective, Sankika Tennakoon, Sarath Perera, D A. Robinson

Dr Duane Robinson

In radial power systems flicker transfer from a higher voltage level (upstream) to a lower voltage level (downstream) is seen to be significantly affected by the downstream load composition. Industrial load bases containing mains connected induction motors are known to be effective in the flicker attenuation process compared to residential load bases containing passive loads. For better understanding of the flicker attenuation influenced by induction motors their dynamic behaviour has to be closely investigated under fluctuating supply conditions. This paper presents the methodology and results of investigations undertaken to examine the response of an induction motor to small perturbations in …


Data Management For Large Scale Power Quality Surveys, Murray-Luke Peard, Sean T. Elphick, Victor W. Smith, Victor J. Gosbell, D A. Robinson Dec 2012

Data Management For Large Scale Power Quality Surveys, Murray-Luke Peard, Sean T. Elphick, Victor W. Smith, Victor J. Gosbell, D A. Robinson

Dr Duane Robinson

For large scale power quality surveys, the management of the large amount of data generated is a major issue. This paper presents solutions to three main areas of data management, viz. a data interchange format, database design and data processing. Consideration of these issues has come about as a result of the Long Term National Power Quality Survey currently being conducted by the University of Wollongong, and reference is made to that specific application for illustrative purposes.


Harmonics And Flicker Levels At A Sub-Transmission Substation: A Measurement Experience, D A. Robinson, Victor J. Gosbell, Sarath Perera, N Browne Dec 2012

Harmonics And Flicker Levels At A Sub-Transmission Substation: A Measurement Experience, D A. Robinson, Victor J. Gosbell, Sarath Perera, N Browne

Dr Duane Robinson

Proactive monitoring of power quality disturbance levels by electricity utilities is vital to allow cost-effective mitigation when disturbances are perceived to be approaching planning levels and also to protect the security of customer installations. Ensuring that disturbance levels are within limits at the HV and EHV points of supply of the network is essential if satisfactory levels downstream are to be maintained. This paper presents discussion on a power quality monitoring campaign performed at the sub-transmission point of supply of a distribution network with the objective of benchmarking background disturbance levels prior to modifications to the substation and to ensure …


Harmonic Impact Of Photovoltaic Inverters On Low Voltage Distribution Systems, Ahmed Latheef, D A. Robinson, Victor J. Gosbell, Victor W. Smith Dec 2012

Harmonic Impact Of Photovoltaic Inverters On Low Voltage Distribution Systems, Ahmed Latheef, D A. Robinson, Victor J. Gosbell, Victor W. Smith

Dr Duane Robinson

The number of installations of photovoltaic solar panels and associated inverter systems within residential premises is increasing. As these systems incorporate a power electronics front end, they will have an influence on the quality of supply in regards to voltage harmonics. This paper investigates the harmonic impact on an LV distribution feeder due to the installation of residential type grid connected photovoltaic inverter systems. To undertake the study an aggregated current source model is proposed for the photovoltaic inverter systems based on measurement data from available literature and the relevant international standards. A typical LV distribution feeder including load arrangements …


Harmonic Survey Of An Mv Distribution System, Victor J. Gosbell, Damian Mannix, D A. Robinson, Sarath Perera Dec 2012

Harmonic Survey Of An Mv Distribution System, Victor J. Gosbell, Damian Mannix, D A. Robinson, Sarath Perera

Dr Duane Robinson

The harmonic survey of a medium voltage distribution system involves three major aspects: (i) the choice of harmonic monitor, (ii) the choice of monitoring site, (iii) processing and presentation of results. As well as a discussion of the methodology for these aspects, the paper will discuss the harmonic levels measured, the minimum survey requirements for finding useful data and the harmonic parameters of residential, commercial and industrial loads.