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.

Process and apparatus for preparing the surface of a plastic molding by means of an electrical corona discharge

Abstract: Moldings having a thickness of 1 to 60 mm and made of flexible webs or rigid sheet of plastic are passed through a corona discharge treatment system consisting of high-voltage electrodes and a counter-electrode and a high-frequency alternating current voltage of 20 to 25 kHz and 20 to 70 kV is applied to the high-voltage electrodes by a generator. A corona discharge forms in the gap between the high-voltage electrodes and the counter-electrode. An aerosol formed by atomizing a liquid is blown into the corona discharge zone by means of an air or gas stream. The aerosol modifies the surface of the sheet-like molding in the desired manner.

Detection and wavelet analysis of partial discharges using an optical fibre interferometric sensor for high-power transformers

Abstract: The main problem in power transformers is the degradation of the isolation, and partial discharges are a major contribution to this shortcoming. Partial discharges inside medium-and high-power transformers generate ultrasonic pressure waves which are usually detected by using acoustic piezoelectric sensors placed outside the transformers. In this paper we describe an optical fibre interferometric sensor we are developing for the detection and location of partial discharges by measuring inside the power transformers. This non-intrusive optical fibre sensor allows a high level of sensitivity to be achieved for the typical small pressure variations created by partial discharges, specially if compared with the results obtained by acoustic piezoelectric external sensors. We present interferometrically detected levels of partial discharge. These results indicate that the developed optical fibre sensor is able to detect a partial discharge in the range of 103 pC that produces an optical phase shift of about 2 rad with a resolution of 30 pC in charge means. Finally, the wavelet analysis is used to identify the acoustic patterns instead of the more commonly used Fourier analysis. When transforming the measured signal to the frequency domain, the temporal information disappears. But the acoustic signals really contain numerous transitory pieces of information to be considered. By looking at a Fourier-transformed signal it is impossible to state when a particular event took place. The wavelet analysis helps to solve this problem, and some results are presented here to show this.

Partial discharge detection on 320 kV VSC-HVDC XLPE cable with artificial defects under DC voltage

Abstract: VSC-HVDC power transmission systems based on extruded cables are being commissioned with higher rated voltages and longer distances in recent years. In China, the rated voltage of commissioned VSC-HVDC cable projects has been increased from 160 to 200 kV, and then to 320 kV in the past 5 years. To investigate the feasibility of discovering insulation defects of an XLPE HVDC cable system using partial discharge detection under DC voltage, a test cable loop was built using the same batch of 320 kV HVDC XLPE cable used to construct the Xiamen ± 320 kV VSC-HVDC project. Artificial defects of insulation wound and semi-conductive layer tips were designed and constructed at the joint. The two types of defects were effectively detected by the HVDC partial discharge test, and the measured results show distinguished discharge characteristics. Suggestions for determining trigger level and partial discharge inception voltage under DC voltage for partial discharge detection of extruded HVDC cables are given.

Method of diagnosing partial discharge in gas-insulated apparatus and partial discharge diagnosing system for carrying out the same

Abstract: The present invention provides a method of diagnosing a partial discharge in a gas-insulated apparatus and a partial discharge diagnosing system for carrying out the same to achieve highly accurate diagnosis through the detection of a partial discharge signal and diagnosing the partial discharge signal through multiple conditional branching. The partial discharge diagnosing system of the present invention comprises: a partial discharge signal detector for detecting a partial discharge signal representing a partial discharge produced in the gas-insulated apparatus, a signal analyzer for receiving the partial discharge signal detected by the partial discharge detector and analyzing the partial discharge signal, a diagnostic unit for determining a cause of the partial discharge on the basis of results of analysis made by the signal analyzer, and a display unit for displaying results of diagnosis. The diagnostic unit is provided with a diagnostic means to make multiple conditional branching to a plurality of second diagnostic means according to result of diagnosis made by a first diagnostic means, and obtains a result of diagnosis made by the second diagnostic means, thereby achieving highly accurate diagnosis by detecting the partial discharge signal and subjecting the partial discharge signal to multiple conditional branching.

Power electronics and electrical insulation systems - Part 3: Diagnostic properties

Abstract: The paper presents that partial discharge detection is an effective tool to prevent premature breakdown of electrical equipment fed by power electronics. it is recommended that it be used as a quality control measure in the factory and as an online diagnostic procedure in service.