Topic
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.
Papers published on a yearly basis
Papers
More filters
Enel1
TL;DR: In this article, four methods for partial discharge (PD) detection in gas-insulated substations were considered and laboratory tests were carried out to determine the efficiency of these methods to detect defects and to discriminate among different defect types.
Abstract: Four methods for partial discharge (PD) detection in gas-insulated substations were considered. Laboratory tests were carried out to determine the efficiency of these methods to detect defects and to discriminate among different defect types. The sensitivity of the methods is compared and the applicability of the methods in the field is discussed. In the laboratory the standard PD measuring method showed a good sensitivity to defects. In the field condition the standard PD measuring method can have a sensitivity much lower than in laboratory, due to the rather high noise level expected. In the laboratory two of the alternative PD detection methods (namely the acoustic method and electrical method including a field probe inside the GIS) have shown a sensitivity to fixed-type defect discharges, while showing less efficiency relative to the mobile particles considered in the study. >
59 citations
TL;DR: In this article, the effect of frequency-dependent attenuation in shielded power cable in the presence of thermal noise has been analyzed for both symmetric (Gaussian) and asymmetric (asymmetric) PD-pulse waveforms, under the assumption that the attenuation constant (dB/m or Nepers/m) of the cable is proportional to frequency.
Abstract: Boggs and Stone (1982) defined the fundamental limits to the electrical detection of corona and partial discharge (PD), i.e., wideband detection of a PD-induced pulse in the presence of thermal noise. This paper treated the effect of frequency-dependent attenuation in shielded power cable in that context. However, most of the plots in that paper were the result of numerical computations. In the same year, Stone and Boggs set out a theory for high-frequency attenuation of shielded power cable. They showed good agreement between attenuation predicted from measured material properties and measured, high-frequency attenuation of shielded power cable. Since 1982, measurements of high-frequency cable attenuation have been reported by a number of authors for a variety of cables. In addition, software tools have become available that facilitate an analytic solution for the parameters of interest. This article summarizes the theory for PD propagation in shielded power cable for both symmetric (Gaussian) and asymmetric PD-pulse waveforms, based on the assumption that the attenuation constant (dB/m or Nepers/m) of the cable is proportional to frequency. This appears to be the most complete possible analytic exposition of PD attenuation in shielded-power cable, which has obvious applications to field PD measurements of such cable.
59 citations
TL;DR: In this paper, the authors described and evaluated acoustic waveguides for diagnostics of partial discharge (PD) in electrical insulation and dielectrics, and showed how the use of acoustic waveguide can improve diagnostic PD measurements in hostile and inaccessible locations.
Abstract: Acoustical waves travel by molecular interaction, and as a consequence, wave attenuation and transit time can be extremely sensitive to changes in the media in which they propagate. With careful acoustic measurements, a wide variety of media properties can be monitored. These range from variations in gas mixtures and pressure, to changes in material density, porosity, and crystal size and orientation. Acoustical technology can also be applied in the listening mode to sense the tiny acoustic emissions from partial discharges in dielectrics, and from stress, strain, and other events. Many of these acoustic techniques are ideal for applying to the science of electrical insulation and dielectrics, and in this paper these different methods are described and evaluated. The subject is introduced with an outline of ultrasonic partial discharge (PD) diagnostics and nondestructive evaluation, with emphasis on acoustic factors which affect accuracy. It is then shown how the use of acoustic waveguides can improve diagnostic PD measurements in hostile and inaccessible locations. In a completely different application, a technique is described in which sound velocity measurements in gas mixtures are used for predicting electrical strength. Other valuable acoustical applications which are outlined are the monitoring of sounds from bouncing particles on metal surfaces and from gas bubbles generated in liquid dielectrics. From this latter phenomenon the temperature of a hot metal surface in a liquid can be estimated. A related subject which is also discussed is the attenuation of sound waves by gas bubbles in a liquid dielectric.
59 citations
TL;DR: In this paper, the feasibility of using a very high frequency capacitive coupler technique to detect and locate partial discharge (PD) activity within HV cables and in particular cable joints has been investigated.
Abstract: In order to detect and locate partial discharge (PD) activity within HV cables and in particular cable joints, the feasibility of using a very high frequency WHO capacitive coupler technique has been investigated. In addition, an alternative PD offline test method for cable joints or cable sections within long cable systems has been developed. By energising the joint or a short section of the cable screen only this method has the advantage of reducing the power supply requirement of the test source. The application of capacitive couplers for this PD offline test method has been investigated. In order to use this approach there must be an insulation gap between the coupler and the outer sheath of the test cable. The effect of this gap on measured sensitivity has been investigated experimentally and through the use of a simulation model. Obtained results are in good agreement. Cross-correlation techniques have been implemented to automatically estimate the signal time of flight from different-coupler outputs. Methods of calibrating the coupler applied to the alternative PD offline test method have also been investigated.
59 citations
TL;DR: In this article, the decelerated swirling flow into the discharge cone of a model Francis turbine operated at variable discharge and constant head was analyzed using an axisymmetric turbulent swirling flow model and a corresponding simplified computational domain.
Abstract: We perform a numerical analysis of the decelerated swirling flow into the discharge cone of a model Francis turbine operated at variable discharge and constant head, using an axisymmetric turbulent swirling flow model and a corresponding simplified computational domain. Inlet boundary conditions correspond to velocity and turbulent kinetic energy profiles measured downstream the Francis runner. Our numerical results are validated against experimental data on a survey section further downstream in the cone, showing that the Reynolds stress turbulence model with a quadratic pressure-strain term correctly captures the flow field. It is shown that the diffuser performance quickly deteriorates as the turbine discharge decreases, due to the occurrence and development of vortex breakdown, with a central quasistagnant region. We investigate a novel flow control technique, which uses a water jet injected from the runner crown tip along the axis. It is shown that the jet discharge can be optimized for minimum overall losses, while the vortex breakdown is eliminated. This flow control method is useful for mitigating the Francis turbine flow instabilities when operating at partial discharge.
59 citations