A correlation method for detection of partial discharges in transformers
TL;DR: In this article, a correlation method is proposed for the location of partial discharge within a winding and experimental results on a lumped parameter model of a winding are shown to prove the feasibility of the method.
Abstract: A correlation method is proposed for the location of partial discharge within a winding. Theoretical simulations and experimental results on a lumped parameter model of a winding are shown to prove the feasibility of the method.
Citations
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TL;DR: In this article, the principles of vector space representation of signals are effectively adopted in the measured transient signals during the impulse testing of transformers and shunt reactor, and the mutual effective coefficient makes a best mutual matches through appropriate mathematical formulation to provide the occurrence or non-occurrence of faults.
7 citations
TL;DR: In this paper, the time delay between simultaneously measured signals is calculated and further extended to identify the impulse fault in transformers using Granger causality analysis, and the principle of Bayesian information criterion is used to estimate the minimum number of lags.
Abstract: Summary
One of the important research areas in transient phenomena is sensitive recognition of fault in the complicated insulation system of transformer to make a decision about either go (acceptance) or no-go criterion after impulse test at factory. The existing methods are, in principle, able to indicate the delay in coupling between the signals, but inferring causality from the time delay is not always straightforward. In this paper, the time delay between simultaneously measured signals is calculated and further extended to identify the impulse fault in transformers using Granger causality analysis. The principle of Bayesian information criterion is used in Granger causality analysis to estimate the minimum number of lags. Granger causality analysis enables the calculation of neutral current signal for any input excitation of full wave and chopped wave impulse for typical power transformers. The experimental studies are performed on 60/90 MVA (132/33 kV) and 150/200/250 MVA (500/275/33 kV) transformers to prove the feasibility of the analysis. Copyright © 2015 John Wiley & Sons, Ltd.
4 citations
TL;DR: In this article, an approach based on the energy characteristics of the PD signal is proposed to locate PD inside the winding of a vacuum cast coil transformer, and the proposed method is verified using the winding and the localization results reveal the feasibility of the proposed algorithm in locating PDs over existing localization algorithms.
Abstract: Localization of partial discharge (PD) is a reliable and necessary technique for early prediction of impending failure in transformer windings. Different PD sources have diverse impacts on insulation, and PDs measured at different locations exhibit unique energy characteristics. An approach based on the energy characteristics of the PD signal is proposed here to locate PD inside the winding. An electrical detection method has been considered with PD pulses measured at the top and bottom of the winding through high-frequency current transformers (HFCTs). To reveal multiscale intrinsic characteristics of the PD signal, authors extracted intrinsic mode function (IMF) using ensemble empirical mode decomposition (EEMD). Next, the instantaneous energy distribution-permutation entropy (PE-IED) values of the first several IMFs were calculated to capture the energy of the PD. Then, dimensionality reduction was ensured by the fast principal component analysis that uses the fixed-point algorithm method. Finally, adaptive density-based clustering using the nearest neighbor graph (ADBSCAN-NNG) approach is proposed to identify the local high-density energy components. The proposed method is verified using the winding of a vacuum cast coil transformer and the localization results reveal the feasibility of the proposed method in locating PDs over existing localization algorithms. The reduced complexity of the proposed algorithm ensures the accurate onsite PD localization in transformer windings.
4 citations
Proceedings Article•
01 Dec 2007TL;DR: In this paper, a correlation method is proposed for the location of partial discharges within a transformer winding, and simulations are performed on lumped parameter models of layer, continuous disc and interleaved winding to prove the feasibility of the method.
Abstract: Partial discharges (PDs) are major sources of insulation failures in power transformers A correlation method is proposed for the location of partial discharges within a transformer winding Simulations are performed on lumped parameter models of layer, continuous disc and interleaved winding to prove the feasibility of the method
3 citations
3 citations
References
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Book•
01 Jan 1971
TL;DR: In underwater sonar systems, external acoustic noise is generated by waves and wind on the water surface, by biological agents (fish, prawns, etc.), and by man-made sources such as engine noise.
Abstract: Probability. Random Processes. Narrowband Signals. Gaussian Derived Processes. Hypothesis Testing. Detection of Known Signals. Detection of Signals with Random Parameters. Multiple Pulse Detection of Signals. Detection of Signals in Colored Gaussian Noise. Estimation of Signal Parameters. Extensions. References. Bibliography. Index.
1,421 citations
"A correlation method for detection ..." refers background or methods in this paper
...It is also known that using this method one can a priori estimate the probability of error in detection [5]....
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...The term is used to normalize the energy of the signals [5]....
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...SIGNAL DETECTION USING CORRELATION The correlation method is known to be optimum for detecting a pulse of known shape contaminated by additive noise with known spectral density [5]....
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TL;DR: In this paper, a quasi-simultaneous detection and location of internal defects in power transformers is presented, where the response of the insulating system to PD signals injected at least at three different sites of each winding (top, center, bottom) is calculated, or measured at the signal tap-off points (i.e., bushings).
Abstract: With the development of fast, and low-cost analog-digital converters (ADCs) and new mathematical procedures for waveform description, e.g., time encoded signal processing and recognition (TESPAR), novel approaches to detect and locate internal defects in the insulation of power transformers become feasible if the following requirements are fulfilled: the equivalent circuit of the insulating system, suitable for the fast partial discharge (PD) signals with risetimes of approximately 10 ns, is known; the response of the insulating system to PD signals injected at least at three different sites of each winding (top, center, bottom) is calculated, or measured at the signal tap-off points (i.e., bushings); and the pattern matrix of all calculated or measured signals exists: e.g., encoded and signal processes with TESPAR as a reference. The above mentioned requirements are examined for quasi-simultaneous detection and location of internal defects in power transformers. The method is applied to PD measurements on power transformers. >
79 citations
TL;DR: In this paper, the capacitatively transferred components of the input pulse along the windings in the appropriate frequency range were extracted by the aid of digital filtering techniques, and good agreement between measured and theoretical distributions was obtained.
Abstract: The capacitative network representation of transformer windings has long been used for the study of pulse distribution along the windings. However, the author's test results and those published in the literature show that theoretical analysis based on this equivalent network may not be applicable. It was found that the capacitive network approximations were valid only within certain ranges of frequency. The frequency ranges were determined through the analysis of terminal measurements. The capacitatively transferred components of the input pulse along the windings in the appropriate frequency range were then extracted by the aid of digital filtering techniques, and good agreement between measured and theoretical distributions was obtained. These techniques, in conjunction with a new straight-line interpolation method, were employed to locate simulated partial discharges in a 66 and 132 kV transformer winding. Measurement results showed that an accuracy of better than 5% of winding length was obtained. >
75 citations
"A correlation method for detection ..." refers methods in this paper
...ANUMBER OF methods have been proposed for the location of partial discharges (PDs) within windings [1]–[3]....
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01 Sep 2000
TL;DR: In this paper, the authors used feature template matching to locate the source of partial discharge in a power transformer with a continuous disc type winding, which required knowledge about the physical geometry and design parameters of the transformer and also information about the characteristics of how the pulses caused by the PD propagate through the winding.
Abstract: In a power transformer, high levels of partial discharge activity may lead to an insulation failure. If a partial discharge (PD) could be detected and located before the insulation fails, the transformer could be repaired or replaced before any consumers connected to the transformer lose supply. A technique is described in the paper that can be used to locate a PD in a power transformer with a continuous disc type winding. The technique requires knowledge about the physical geometry and design parameters of the transformer and also information about the characteristics of how the pulse or pulses caused by the PD propagate through the winding. The latter is difficult to obtain and consequently numerous simulation studies with slightly different assumptions were necessary before the technique could be considered validated. This involved analysing the data available at the terminals when a PD occurred in the winding and trying to extract the features related to the PD location. An algorithm using feature template matching has been used to locate the PD source in a 110 kV continuous disc type winding. Experimental tests carried out on this type of winding were extremely important in verifying the validity of the PD location algorithm. Results indicate that a location accuracy of better than 5% of the winding length is normally achieved.
44 citations
"A correlation method for detection ..." refers methods in this paper
...ANUMBER OF methods have been proposed for the location of partial discharges (PDs) within windings [1]–[3]....
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19 Oct 2003
TL;DR: In this article, a matched filter approach is proposed for the location of a partial discharge within a winding, which does not need isolation of the capacitively transferred components and can be applied to the determination of location of PD during impulse tests.
Abstract: A matched filter approach is proposed for the location of a partial discharge within a winding. The approach is very general and does not need isolation of the capacitively transferred components. Simulations are performed on a lumped parameter model of a layer winding to prove the feasibility of the method. Experiments are also performed on a layer winding in order to validate the method. It is possible to extend the method to the determination of location of PD during impulse tests.
21 citations
"A correlation method for detection ..." refers methods in this paper
...In this paper, we propose a correlation method for PD location which was briefly described in [4]....
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