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.

Challenges in calibration of the measurement of partial discharges at ultrahigh frequencies in power transformers

Abstract: The detection and measurement of partial discharge (PD) is a well-known method for evaluating the insulation performance of power transformers. According to the IEC 60270 standard, the apparent charge is measured in a frequency range below 1 MHz using an electrical circuit which quantifies only a portion of the discharge energy conducted to the PD detector through the conductors. However, it is also well known that the PD energy is not only conducted but also transmitted via electromagnetic (EM) and optic waves, acoustic waves, and thermal energy.

An Overview of Electrical Tree Growth in Solid Insulating Material with Emphasis of Influencing Factors, Mathematical Models and Tree Suppression

Abstract: Nowadays, the most widely used insulating materials in high voltage equipment such as cables are polymeric insulations due to the numerous merits they possess with regards to electrical performance compared to paper insulations. However, electrical treeing, one of the dielectric pre-breakdown phenomena, has been considered as a major contribution to the failure of insulating polymeric materials. Thus, this paper provides an overview on the factors affecting the initiation and propagation of electrical tree. Discussions on parameters that affect the growth of electrical treeing such as applied voltage, electric field enhancement, partial discharge, frequency of applied voltage and temperature are given. Some discussions on the various models are also highlighted. The tree related models being discussed herein include Weibull, Lognormal, Johnson SB, Dielectric Breakdown Model, Discharge-Avalanche Model, and Field-Driven Tree Growth. In addition, discussions on the use of nano-sized fillers in polymeric insulating material to inhibit electric treeing are highlighted.

Modeling partial discharge phenomena

Abstract: Measurements of partial discharge (PD) activity are a commonly used technique to diagnose the health of insulation material within high voltage plant. The definition of PD is relatively broad, it is generally defined as a localized or confined discharge within an insulating medium [1]. Due to the high electric breakdown strength of insulation materials, PDs typically occur within low density defects in the system. One family of defects which has received significant research attention is air-filled voids, typically spherical or cylindrical, surrounded by solid dielectric material. Experiments have typically used a ‘sandwich’ technique to fabricate cylindrical voids, using three slabs of material with a circular hole drilled into the central slab. The slabs are then pressed together and placed between parallel plate electrodes. A common dielectric material used to fabricate cylindrical voids is LDPE [2]. By injecting air through a syringe before the curing process spherical voids have been fabricated in epoxy resins [3,4] and silicone rubber [5].

Effect of dielectric surfaces on the nature of partial discharges

Abstract: A mathematical model for a short gap breakdown in air was employed to examine the nature of the initiating discharge on the dielectric surface of a dielectric/metallic electrode gap of 0.500 mm separation in a uniform electric field at atmospheric pressure. The calculations demonstrate that in the absence of field enhancing surface asperities, the incipient discharge, occurring on a dielectric surface, exhibits the pronounced breakdown channel expansion characteristic of pulseless glow discharges.

Detection of SF 6 decomposition products generated by DC corona discharge using a carbon nanotube gas sensor

Abstract: This paper describes application of carbon nanotube (CNT) gas sensor to detection of SF6 decomposition products generated by positive or negative DC corona discharge. The present authors have demonstrated CNT gas sensor-based partial discharge (PD) detection, aiming to develop a new diagnosis method of gas-insulated switchgear (GIS) filled with high pressure SF6 gas. In our previous studies, PD was generated by ac high voltage because most of GIS are designed and operated for conventional high voltage ac (HVAC) power transmission lines. In recent years, however, the electrical power industry has shown a trend shifting from HVAC to high voltage dc (HVDC) power transmission, which has many advantages such as higher power capacity and lower power loss. This technological trend motivated us to explore and expand the application of CNT gas sensor to detection of SF6 decomposition products generated by dc corona discharges. It was found that the CNT gas sensor exhibited significant response to dc corona discharge depending on the voltage polarity. In order to elucidate the mechanism of the polarity effect, SF6 decomposition products were analyzed by Fourier transformation infrared (FTIR) spectroscopy as well as using a gas detection tube. Based on comparison between the polarity effects on the CNT sensor response and the decomposition products, a possible contribution of HF to the CNT gas sensor response was suggested.