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.

Static electrification and partial discharges induced by oil flow in power transformers

Abstract: This paper presents the study of the major parameters on static electrification, using full-scale shell type transformers (570 MVA, 405 kV and 100 MVA, 500 kV). The consequences of static electrification on the dielectric strength and the conditions of partial discharge occurrence also are studied with oil flow rate up to 5 times the nominal value. It shows that the leakage currents are strongly influenced by temperature, applied voltage and oil flow rate Q. The latter is the most influential parameter. The winding leakage current I varies as Q/sup n/, where 1/spl les/n/spl les/3. The maximum value of I is observed at room temperature (20/spl deg/C) when the transformer is energized. >

Experience with optical partial discharge detection

Abstract: Partial discharge (PD) diagnostics was used to evaluate electrical insulations of high voltage equipment as a quality control and to detect insulation deterioration. Improvements, new developments as well as lower costs of sensors, electronics and processing units are some reasons for the increasing usage of PD measurements. The paper presents investigations in the area of optical partial discharge measurement technique. In an overview, PD measurement systems were presented, advantages and disadvantages of the optical method were discussed. An unconventional optical partial discharge detection system was developed and comparative measurements to a conventional electrical PD measurement system were accomplished. The system was tested by using a PD source in air or alternatively in oil to evaluate the sensitivity and the impulse behaviour in correlation to the conventional measurement technique.

Separation of partial discharges from pulse-shaped noise signals with the help of neural networks

Abstract: The paper introduces a method to separate partial discharges (PDs) from pulse-shaped noise signals using a neural network. After a short introduction to the problems of PD measurements on-site, the structure of neural networks and their ability for pattern recognition is presented. The adaptive resonance theory (ART) architectures, which are suitable for PD measurement, and especially the fast simulating algorithm ART 2-A, are explained. To ensure the suitability of the chosen network for PD measurement, the electrical noises and PD signals measured on a distribution transformer as well as on a high voltage transformer are classified. Furthermore, it is shown that the same algorithm with changed parameters can make a contribution to PD localisation in a transformer. This takes place with the help of calibration pulses, which are injected in different points of a transformer coil. It is shown that the ART 2-A network is able to classify these pulses in accordance with their origin for the distribution transformer. The paper ends with an examination of the signals measured on a power transformer under high voltage on-site.

On the regime transitions during the formation of an atmospheric pressure dielectric barrier glow discharge

Abstract: The atmospheric pressure dielectric barrier discharge in helium is a pulsed discharge in nature If during the electrical current pulse a glow discharge is reached, then this pulse will last only a few microseconds in operating periods of sinusoidal voltage with lengths of about 10 to 100 µs In this paper we demonstrate that right before a glow discharge is reached, the discharge very closely resembles the commonly assumed Townsend discharge structure, but actually contains some significant differing features and hence should not be considered as a Townsend discharge In order to clarify this, we present calculation results of high time and space resolution of the pulse formation The results indicate that indeed a maximum of ionization is formed at the anode, but that the level of ionization remains high and that the electric field at that time is significantly disturbed Our results also show where this intermediate structure comes from (Some figures in this article are in colour only in the electronic version)

Electrical aging lifetime model of oil-impregnated paper under pulsating DC voltage influenced by temperature

Abstract: Main insulation of windings connected with valves in high voltage direct current (HVDC) convert transformers withstands pulsating DC voltages. This paper presents breakdown properties of oil-impregnated paper under pulsating DC voltages at different temperatures. Progressive stress tests were carried out to obtain breakdown voltages of oil-impregnated paper with thickness of 0.2 mm under pulsating DC voltages at different temperatures. Constant stress tests were executed to measure time to breakdown of the oil-paper specimens. Both types of the experiments were also undertaken under either AC or DC voltages. An electrical aging lifetime model was proposed for the oil-impregnated paper, and parameters of the electrical aging lifetime model were presented. Experiments and analysis results show that the breakdown voltages and time to breakdown of oil-paper insulation are influenced by temperature significantly.