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.

Effects of self-erasing discharges on the uniformity of the dielectric barrier discharge

Abstract: Atmospheric pressure discharges in Ne, N2 and N2/O2 gases have been investigated with a novel high-voltage pulse power supply. Three characteristic types of discharge modes were observed: (1) diffuse glow discharge seen in Ne gas both with the eye and high-speed camera; (2) diffuse glow-like discharge in N2 gas observed with the eye, but seen as a vague filamentary discharge with a high-speed camera; and (3) clear filamentary discharge in N2/O2 gas mixture both with the eye and high-speed camera. Characteristics in the current and voltage waveforms revealed that the existence of the second voltage with opposite polarity following the first impulse voltage was important to have a diffuse glow-like discharge. This suggests that elimination of the memory effect by non-uniformly distributed charges on the surface is important for obtaining the diffuse mode because the non-uniformity triggers a positive feedback to the current constriction at the points with higher charge density, and results in filamentation of the discharge.

Low-pressure hollow-cathode glow discharge plasma for broad beam gaseous ion source

Abstract: We have developed a hollow-cathode glow discharge plasma for a dc broad beam ion source. For a broad beam ion source, it is hard to obtain adequate pressure drop between the discharge space and the extraction region. The high-current low-voltage mode of discharge is limited to a pressure about 10−3 Torr, but for stable extraction of ions without breakdown the pressure needs to be at least one order of magnitude lower. To decrease the limited operation pressure for the high-current mode of the hollow-cathode glow, an external electron beam was used. These electrons were generated in a “keep-alive” discharge and are accelerated in the cathode layer of the primary discharge. In this way we successfully decreased the operation pressure to 10−4–3×10−5 Torr, as well as reaching a value of the discharge voltage as low as 80 V. The characteristics of this discharge system are presented, and the influence of external electrons on the discharge parameters is discussed.

Automized Recognition of Partial Discharges in Cavities

Abstract: A simultaneous analysis of several parameters was used to study the possibilities of recognizing specific patterns of partial discharges in a dielectric. A computer aided discharge analyzer was used to test two types of cavities: dielectric bounded and electrode bounded. The following discharge parameters were registered: ignition voltage, discharge magnitude and phase position. The discharge data were processed using statistical tools like cross-correlation and skewness. A combination of statistical and discharge parameters offers a strong discriminator between the two types of cavities studied and can be a usefull step into developing an expert system for the recognition of different kinds of defects in insulation.

In-service evaluation of motor and generator stator windings using partial discharge tests

Abstract: Partial discharges (corona) are a symptom of most types of deterioration of motor and generator stator windings rated 4 kV and above. Experience indicates that partial discharges occur years before failure. This leaves sufficient time to plan corrective maintenance to avoid the in-service failure of the motor or generator. This paper describes a new type of partial discharge test which can be performed by plant personnel during normal operation of the machine, thus enabling all users of large machines to plan maintenance. The key requirement of the new test is to remove all the interference caused by other sparking and discharging sources in a plant. Such noise has lead to false indications of stator winding deterioration in the past. The new test uses either high-voltage capacitive sensors, high-frequency current transformers, or 1000 MHz electromagnetic couplers to detect the discharge signals. These signals are processed on a pulse-by-pulse basis by a specialized electronic instrument to remove noise and the remaining partial discharges are then categorized according to number, magnitude, and phase position. The test has been implemented on over 100 machines, and the results appear promising. >

Numerical simulation and experimental study of the corona and glow regime of a negative pin-to-plate discharge in flowing ambient air

Abstract: In a negative pin-to-plate discharge in ambient air, three different modes can be observed: corona, glow and spark. The experimental results of this paper reveal the effect of the anode geometry on the extent of the glow regime. A quasi-two-dimensional model is applied to reconstruct the experimental current–voltage characteristics of negative corona discharges with curved anode surfaces. For a sufficiently large discharge current, the model yields a discharge structure that is similar to that of a low-pressure glow discharge.