Partial discharge

About: Partial discharge is a research topic. Over the lifetime, 13997 publications have been published within this topic receiving 102058 citations. The topic is also known as: PD.

Prediction of Treeing Breakdown from Pulse Height of Partial Discharge on Voltage-Phase Angle

Abstract: This paper describes the change in the partial discharge (PD) characteristics due to the growth of electrical trees in insulating materials under the application of an AC voltage. An electrical tree consists of branch-like dielectric breakdown paths. Investigation of a number of characteristic PD parameters shows that the φ-q distribution profile has a good correlation with tree growth. The φ-q distribution expresses the average pulse height as a function of the AC voltage-phase angle. The distribution indicates a common profile for trees growing in both epoxy resin and polyethylene. Tree growth in these materials can thus be detected by monitoring the profile of the φ-q distribution, and the final breakdown can be predicted from the tree growth.

On-Line Digital Computer System for Measurementof Partial Discharges in Insulation Structures

Abstract: An outline is given of the nature of partial dischargesoccurring in insulation structures, in particular in oil impregnatedconfigurations. It is suggested that conventional discharge measuringsystems are not always able to assess significant parameters becausemuch of the available information is inevitably discarded during thehigh-voltage tests. A mobile computer-based data-acquisition system hasbeen developed for recording and storing, in digital form, the statisticalinformation present. The equipment described is capable of recordingand analyzing the small disturbances produced by partial dischargesunder practical conditions. The computer programs enable the time ofoccurrence and the magnitude and polarity of the pulses to be recorded;in addition, digital transient-event recorders can be programmed toaccept slow partial discharge shapes or ultrasonic transducer outputsfor storage in the computer system. A wide range of playback programsare described and possible methods of presenting the results are discussedusing examples obtained from a 50-kV high-voltage test arrangement.The problems of hardware development are outlined, including thoseof interfacing and operation in hostile environments. The economics ofsuch a system are mentioned and methods of effecting cost reductionsare suggested.Finally, this paper suggests that if on-line characterization of partialdischarges becomes possible then the results of discharge measurementswill have greater significance than at present, especially in those borderlinecases where interpretation of results is difficult.

Measurement and simulation of partial discharge in oil impregnated pressboard with an electrical aging process

Abstract: The continuous test on oil impregnated pressboard insulation with internal void defect was developed and the phase resolved partial discharge (PRPD) pattern of partial discharge (PD) signals during the electrical aging process was measured. Two different void structures which have different void volume were used in this experiment. It shows that the PD pattern could be classified into five stages and a great diversity in the first four stages is observed. The larger void volume leads to larger PD magnitude. The computer numerical simulation model which is based on a physical discharge process was used and the causes of PD pattern change were interpreted by comparison with computer numerical simulation results. The initial values and change tendency of gas pressure and surface conductivity were determined through experiment. The model parameters in different stages have been studied as well as the insight into the physical changes in the void during electrical aging. The results provide rules for the identification of the electrical aging stage through the partial discharge measurements.

Tree growth monitoring by means of digital partial discharge measurements

Abstract: In this work results relevant to electrical treeing tests performed on several ethylvinylacetate EVA (with different vinylacetate percentage) and on cross linked polyethylene (XLPE) (of two different lots) polymer materials are presented. During the tree growth the partial discharges (PDs) were monitored by means of a digital PD acquisition system and the tree morphologies were optically evidenced by means of video recorder equipment. The PD acquired data, the outcome of the video monitoring and the time-to-breakdown were off-line processed and analysed. In this way, two main results were obtained: the first one, applicable to this kind of laboratory treeing tests, is related to the possibility of predicting the lifetime of the specimens, considering a specific PD measurement derived quantity; the second one demonstrates the possibility to detect the tree morphology considering the phase-number distribution obtained by the digital PD measurement. The presented test procedures are deemed to have a potential for diagnostic applications.

Characteristics of PD pulses in electrical trees and interfaces in extruded cables

Abstract: The characteristics of partial discharge (PD) occurring within electrical trees in extruded cable insulation, and also at model interfaces between a cable and its accessories, have been investigated. A wideband PD detection system was used that enabled the true shape of the PD pulses to be measured. The rise- and fall-times, pulse width, amplitude and frequency of the pulses were recorded as electrical trees grew through the insulation, and also as the tracking progressed along a model cable/accessory interface. The PD pulse characteristics in electrical trees varied with time of voltage application and also with the electrical stress in the insulation. Differences in the PD characteristics of electrical trees in the bulk of a polymer and at interfaces between polymers were observed.