Papers by Trevor Blackburn
Partial discharge (PD) is a phenomenon that commonly occurs in the insulation of power system equ... more Partial discharge (PD) is a phenomenon that commonly occurs in the insulation of power system equipment. In this paper, PDs occurring in a single void and multi-voids were investigated. Air voids at atmospheric pressure were injected into cylindrical epoxy resin blocks to create test samples with single void and multi-voids. PDs from the samples were recorded and further analyzed using
Australian Journal of Electrical and Electronics Engineering, 2009
ABSTRACT Partial discharge (PD) is a common phenomenon which occurs in insulation of high voltage... more ABSTRACT Partial discharge (PD) is a common phenomenon which occurs in insulation of high voltage equipments such as transformers and has a damaging effect to the insulation. In this paper, the application of descriptive data mining on PD occuring in insulating system is shown. Experiments were set up to create three basic types of PD: corona, surface discharges and internal discharges. Partial discharge data were analysed using phase resolved analysis and pulse height analysis. Descriptive data mining was applied on the collected data using decision tree with genetic algorithm (GA) to mine the rules/relationships which can be used to differentiate the PD. These extracted rules are useful as input to predictive data mining such as fuzzy logics.
2007 IEEE Lausanne Power Tech, 2007
Dissolved gas-in-oil analysis (DGA) is a sensitive and reliable technique for the detection of in... more Dissolved gas-in-oil analysis (DGA) is a sensitive and reliable technique for the detection of incipient fault condition within oil-immersed transformers. The presence of certain key gases is monitored and quantified. There are a number of methods developed for analyzing these gases and interpreting their significance: Key Gas, Rogers Ratio, Doernenburg, Logarithmic Nomograph, IEC Ratio and Duval Triangle. This paper investigates
The power transformer is the most expensive, indispensable and arguably the most important equipm... more The power transformer is the most expensive, indispensable and arguably the most important equipment item in a power system Insulation failure in transformers can cause long term interruption to supply and loss of revenue and the condition assessment of the insulation is thus an important maintenance procedure. Oil-impregnated transformer insulation consists of mainly organic materials including mineral oil and cellulose-base paper and pressboard. The operating life of cellulose-based insulation, as with most organic insulation, depends heavily on its operating temperature rise above ambient. This paper reports results of a laboratory-based experimental investigation of partial discharge (PD) activity at high temperature in oil-impregnated insulation. The experiments reported here are part an on-going programme aimed at investigating the way in which insulation deterioration can be monitored and quantified by use of partial discharge diagnostics. Partial discharge patterns were reco...
International Conference on Power Electronics and Drive Systems, 2001
This paper presents voltage control methods to improve the voltage level of a power system whilst... more This paper presents voltage control methods to improve the voltage level of a power system whilst minimizing losses. A B-losses coefficient method is used as alternative means to calculate losses to control the operation of capacitor banks and/or tap changing transformer to minimize losses. A Matlab load flow simulation has been developed to implement a polar Newton-Raphson algorithm and calculate
High Voltage, 2018
Power transformer partial discharge signal measurement using Radio Frequency method has advantage... more Power transformer partial discharge signal measurement using Radio Frequency method has advantages over IEC 60270 'apparent charge' measurement method for online monitoring due to greater immunity against external interference. However, the lack of a well-defined calibration relationship between the two methods is main disadvantage of RF method. Simultaneous measurements, using these two methods, carried out on various transformer PD source models, in laboratory, to investigate main parameters that affect the relationship of results of these two methods. In this paper, factors that influence this relationship are classified into three groups: (i) type of PD sources, (ii) transformer windings as PD signal transmitter, and (iii) the inner structure of the transformer. Firstly, the relationship between these two methods has been investigated for some simple types of PD sources. Subsequently, by adding the winding structure model to the void, which is the PD source, its impact on each measurement method and the relationship between them have been studied. The impact of inner structure on the relation between the two methods is compensated through a formula which is proposed as a means for calibration of the RF partial discharge measurement setup. However to compensate for internal insulating system effects more research is required.
2014 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP), 2014
Very low frequency (VLF) testing refers to AC testing in the frequency range of 0.01 Hz up to 1 H... more Very low frequency (VLF) testing refers to AC testing in the frequency range of 0.01 Hz up to 1 Hz. VLF testing is increasingly becoming popular as an alternative approach for test objects which require significant reactive power such as power cables. However, reliable diagnosis of partial discharge characteristics under VLF voltage excitation is still lacking. The paper presents a comparative study between testing at normal power frequency and at VLF. Corona and surface discharges were produced using a needle/bowl and a short section of 11kV XLPE cable. Experiments were conducted over a range of frequencies from 50 Hz down to 0.08 Hz and the results were analyzed. They showed some similarity of PD characteristics in terms of their phase-resolved patterns. The discrepancies of PD results are described in details.
Proceedings of 5th International Conference on Properties and Applications of Dielectric Materials
... 03P02 Application of Adaptive Filters for the Estimation of Partial Discharge Signals in Nois... more ... 03P02 Application of Adaptive Filters for the Estimation of Partial Discharge Signals in Noisy Environments Abbas Zargari Trevor R. Blackburn Department of Electric Power Engineering The University of New South Wales Sydney 2052, Australia ...
IEEE International Conference on Dielectric Liquids, 2005. ICDL 2005.
In this study a method for selecting optimal wavelet is introduced, which is implemented for eval... more In this study a method for selecting optimal wavelet is introduced, which is implemented for evaluating electrical measured partial discharges on a 66 kV/25 MVA fully interleaved winding of a power transformer. Applying wavelet transform to a signal produces a wavelet detail coefficient distribution throughout the for generating coefficients with maximal values. The basic idea of this method is described
Proceedings of the 7th International Conference on Properties and Applications of Dielectric Materials (Cat. No.03CH37417)
This paper presents a study of the properties of partial discharges at elevated temperature. Part... more This paper presents a study of the properties of partial discharges at elevated temperature. Particular interest was given to new and aged oil-impregnated insulation as applied in power and instrument transformers. The data analysis was focused on the PD quantities that include the peak and average PD magnitudes and the PD repetition rate. In addition to the PD quantities, an investigation of the discharge characteristics using statistical moments was also conducted. Results indicated that the PD quantities and the characteristics of their distributions are greatly affected by the temperature change. Variation in the PD activity was found to be considerable and very dependent on the insulation condition.
Proceedings of 2001 International Symposium on Electrical Insulating Materials (ISEIM 2001). 2001 Asian Conference on Electrical Insulating Diagnosis (ACEID 2001). 33rd Symposium on Electrical and Electronic Insulating Materials and Applications in System
This paper presents the statistical analysis of partial discharge distributions in oil-impregnate... more This paper presents the statistical analysis of partial discharge distributions in oil-impregnated pressboard and paper configurations. The experiment reported here was aimed at an investigation of the characteristics of partial discharges in a cavity for both new and aged oil-impregnated pressboard-paper samples. Two different measurement systems, which provide four different measurement bandwidths were used to observe whether they would produce similar characteristics of discharges. The results indicated that, while there was some general similarity in the shape of PD patterns, a detailed statistical analysis of the PD data showed some significant differences in the results. These differences were significant in terms of the frequency response of the PD sensor systems. As a conclusion, the analysis of such PD data must be performed carefully with particular attention being given to the frequency response.
2006 IEEE 8th International Conference on Properties & applications of Dielectric Materials, 2006
This paper addresses results of PD tests at elevated temperature. Particular interests were given... more This paper addresses results of PD tests at elevated temperature. Particular interests were given to new and aged oil-impregnated pressboards. The aim of this investigation was to study the impact of the particular conditions, such as those encountered in practical situations, on the ageing rate of the insulation material. The investigation was also aimed at an exploration of whether it is possible to quantify the ageing stage of the material by means of parameter analysis of the measured PD distributions. PD data obtained from the experimental work is presented in phase-resolved analysis (PRA) and voltage difference analysis (VDA)
IET Generation, Transmission & Distribution, 2016
High impedance fault (HIF) has long been a challenging problem in network protection due to its r... more High impedance fault (HIF) has long been a challenging problem in network protection due to its random behaviour and low magnitude. The conventional protection devices cannot be utilised since the HIF does not draw enough current to cause tripping. The feature of wavelet transform (WT) which decomposes a signal into different frequency bands and locations in time can be utilised to extract HIF features and detect its occurrence. In the study, HIF arcing currents associated with different types of contact surface are produced by experiments set up in the laboratory. Features of the fault currents are extracted and a new detection criterion is developed based on WT coefficients. Transformer magnetising inrush currents and capacitor switching transients are also produced by experiment and simulation, respectively, to represent transient disturbances commonly occurred in the distribution network. The detection criterion is used to discriminate the HIF from other normal non-fault transient events. Three different types of wavelet are tested and the Daubechies wavelet Db4 gives the best performance based on its detection and discrimination rates. The efficacy of utilising existing conventional current transformers for HIF application is also tested and verified by experiment.
Silicone Rubber Surge Arrester housings that were removed from site were tested under conditions ... more Silicone Rubber Surge Arrester housings that were removed from site were tested under conditions of high humidity and artificial pollution. Surface partial discharge behaviour that occurred was detected and recorded by utilizing the CDA3 Computer based partial discharge analysis system. Statistical properties, in particular skewness and kurtosis, provide some indicator of surface damage on the insulator.
Proceedings of 2005 International Symposium on Electrical Insulating Materials, 2005. (ISEIM 2005)., 2005
This paper provides a brief overview of the main areas of research in high voltage (HV) insulatio... more This paper provides a brief overview of the main areas of research in high voltage (HV) insulation and insulation diagnostics in Australia, particularly at the University of New South Wales, Queensland University of Technology, and the University of Queensland.The main disciplines of activity are those directly associated with condition monitoring of HV equipment and with those dielectric material properties directly applicable to high voltage equipment operation.
Proceedings of the 6th International Conference on Properties and Applications of Dielectric Materials (Cat. No.00CH36347), 2000
This paper presents the characteristics of partial discharge activity in oil-impregnated insulati... more This paper presents the characteristics of partial discharge activity in oil-impregnated insulation under different test voltage frequencies and oil contamination. The aim of this experiment is to investigate the effect of the voltage frequency variation in accelerating the deterioration of this particular insulation. The test results indicate that, for the conditions tested, there is not a linear scaling of the current, power and the repetition rate of the discharges, which may require some re-assessment of the aging determination for such configurations.
The need for on-line monitoring of high voltage cables is a matter of prime importance to the uti... more The need for on-line monitoring of high voltage cables is a matter of prime importance to the utility asset manager because of the potential disruption to consumers if a cable fails. Such monitoring is a difficult proposition and a number of different diagnostic methods have been developed. Partial discharge monitoring, although suffering from possible access problems, is potentially the most useful diagnostic as it can be used both as a monitor of instantaneous condition also as a sensitive monitor for insulation deterioration over time. A partial discharge measurement system has been developed to monitor on-line the insulation condition of high-voltage cables and their accessories. The system measures partial discharge activity using two different high frequency, non-intrusive, sensors. No outage is required for fitting the sensors to cables. Techniques to overcome the problem of significant interference on-site were investigated including choice of detection frequency by filterin...
IEEE Transactions on Power Delivery, 2019
Partial discharge (PD) measurement and identification have great importance to condition monitori... more Partial discharge (PD) measurement and identification have great importance to condition monitoring of power transformers. In this paper, a new method for recognition of single and multi-source of PD based on extraction of high level image features has been introduced. A database, involving 365 samples of phase-resolved PD (PRPD) data, is developed by measurement carried out on transformer artificial defect models (having different sizes of defect) under a specific applied voltage, to be used for proposed algorithm validation. In the first step, each set of PRPD data is converted into grayscale images to represent different PD defects. Two “image feature extraction” methods, the Local Binary Pattern (LBP), and the Histogram of Oriented Gradient (HOG), are employed to extract features from the obtained gray scale images. Different variants of Support Vector Machine (SVM) are adjusted for optimal classification of PD sources in this process. Impact of the employed parameters in the image processing such as image resolution, random noise, and phase shift, on identification accuracy is investigated and addressed. It is shown that by using HOG-SVM method 99.3% accuracy can be achieved. This is hardly affected by various external factors. Two case studies have been conducted on multi-source PD for evaluating the performance of the proposed algorithm. A void defect is implemented into the transformer model and the resultant recorded signal is used for the study. The DBSCAN algorithm is used as the mean of PD source clustering and sub-PRPD pattern development. It is shown that HOG-SVM method has superior performance in identifying active sources, under sub-PRPD pattern application.
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Papers by Trevor Blackburn