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.

Simulation of Partial Discharge in High Voltage Power Equipment

Abstract: In high voltage (HV) electrical power system, variety of solid, liquid and gaseous materials are used for insulation purpose to protect the incipient failure inside the HV power equipment. Among these the solid insulation is widely used for high voltage power equipment HV electrical power system. Most of insulating materials are not perfect in all respect and contains always some impurities. The presence of air bubble is one of such impurities in insulating materials and highly undesirable for such type of insulation which causes a local weak zone inside the insulator. Insulation of the HV power equipment gradually degrades inside the insulator due to cumulative effect of electrical, chemical and thermal stress. Due to the high voltage stress the weak zone inside the insulator causes the partial discharge (PD) which is known as local electrical breakdown. As a result the insulation properties of such materials are enormously degrades its quality due to the PD. In this work, the simulation of PD activity due to presence of a small cylindrical void inside the solid insulation material of high voltage power equipment is studied with the MATLAB Simulink platform.

A versatile method to study electrical treeing in polymeric materials

Abstract: Electrical treeing in high voltage cable insulation has been studied widely as it is one of the major breakdown mechanisms for solid dielectrics subjected to high electrical stresses. The most frequently experimental set-up used to study electrical treeing is utilizing needles to achieve a high divergent field to promote the initiation of electrical trees. In this paper a new type of electrode configuration is described, which will be beneficial when examining electrical treeing in terms of both the capability to follow the course of events in real time and the small amount of insulation material is needed. This new electrode configuration makes use of a thin tungsten wire as electrode to obtain the high divergent electrical stress needed to initiate electrical trees. Multiple electrical trees are at times formed at different points along the wire during the testing, this indicates that the field are homogenous along the wire. This allows for determining the tree initiation field and the rate of tree growth. It is also shown that this electrode configuration is able to distinguish the increased electrical tree inception obtained by the addition of voltage stabilizers.

Separation of Radio-Frequency Sources and Localization of Partial Discharges in Noisy Environments

Abstract: The detection of partial discharges (PD) can help in early-warning detection systems to protect critical assets in power systems. The radio-frequency emission of these events can be measured with antennas even when the equipment is in service which reduces dramatically the maintenance costs and favours the implementation of condition-based monitoring systems. The drawback of these type of measurements is the difficulty of having a reference signal to study the events in a classical phase-resolved partial discharge pattern (PRPD). Therefore, in open-air substations and overhead lines where interferences from radio and TV broadcasting and mobile communications are important sources of noise and other pulsed interferences from rectifiers or inverters can be present, it is difficult to identify whether there is partial discharges activity or not. This paper proposes a robust method to separate the events captured with the antennas, identify which of them are partial discharges and localize the piece of equipment that is having problems. The separation is done with power ratio (PR) maps based on the spectral characteristics of the signal and the identification of the type of event is done localizing the source with an array of four antennas. Several classical methods to calculate the time differences of arrival (TDOA) of the emission to the antennas have been tested, and the localization is done using particle swarm optimization (PSO) to minimize a distance function.

Principal Component and Hierarchical Cluster Analyses as Applied to Transformer Partial Discharge Data With Particular Reference to Transformer Condition Monitoring

Abstract: This paper analyses partial discharges obtained by remote radiometric measurements from a power transformer with a known internal defect. Since fingerprints of remote radiometric measurements are not available, the formation of clusters with similar features obtained from captured partial discharge data is crucial. Hierarchical cluster analysis technique is used as a method for grouping different signals. Investigation based on Euclidean and Mahalanobis distance measures and Ward and Average linkage algorithms were performed on partial discharge data pre-processed by principal component analysis. As a result of the analysis, a clear separation of partial discharges emanating from the transformer and discharges emanating from its surrounding is achieved; this in turn should enhance the methodologies for condition monitoring of power transformers.

A minicomputer-based partial discharge measurement system

Abstract: In order to make a comprehensive study of partial discharge phenomena, an advanced measurement system has been developed, which utilizes a minicomputer having functions such as memory, data processing and judgement. The system is so designed to process positive and negative pulse trains appearing in phase of a.c. voltage and is provided basically with three functions; repetition vs. pulse height characteristics, time and phase domain pulse height distribution characteristics and phase domain pulse repetition characteristics. Several techniques are introduced to improve signal-to-noise ratio in partial discharge measurement. It can accommodate further modification in data processing when it is necessary in future.