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.

Study of slot partial discharges in air-cooled generators

Abstract: Two laboratory experiments were set up in order to investigate the influence of different parameters on slot partial discharge (PD) activity. The goal of the first experiment was to establish the relative importance of temperature and gap size on slot partial discharges (PDs). The second experiment was used to determine how different stresses (e.g. electrical, thermal and mechanical) influence the discharge mechanisms of stator bars affected by slot PDs. Finally, the results obtained in the laboratory were confirmed when compared with actual field measurements on a generator.

Frequency domain correlation technique for PD location in transformer winding

Abstract: Partial discharge (PD) is one of the sources of insulation failures in Power transformers. Knowledge of the PD source locations are important for transformer maintenance and repair. Due to the complex structure of the transformer, it is very difficult to locate the PD accurately in transformer winding. Correlation methods are applied to locate the PD source across the winding. The PD across parts of the winding are simulated by applying voltage pulse across the sections. The winding response for a reference PD impulse across transformer sections are taken as base for correlation and correlated with winding response of PD impulse across any section with different PD pulse widths. In this paper the limitation of time domain correlation method in locating PD in transformer windings is found out. To overcome the limitation of time domain correlation method, frequency domain correlation with Gram Schmidt orthogonalization is proposed. Simulation and experiments are performed on layer, continuous disc and interleaved windings to prove the feasibility of the proposed method.

Partial discharge behavior of mineral oil based nanofluids

Abstract: A previous study showed that both mineral oil based nanofluids with 001% silica mass fraction and with 01% fullerene mass fraction have a higher AC breakdown strength than mineral oil Breakdown occurs following discharge initiation and propagation in the oil The breakdown strength value alone provides little information on the discharge process Therefore, it is important to investigate the details of the discharge mechanisms in mineral oil and in nanofluids Hence, this study focuses on the partial discharge (PD) behavior of mineral oil, silica and fullerene nanofluids The total charge, voltage and pulse shape were recorded with the help of a high bandwidth PD measuring system The discharge mechanism in mineral oil appeared to depend strongly on the polarity of the applied DC voltage Under positive DC voltage, the silica and the fullerene nanofluids show increased inception voltage and a reduction of the total discharge magnitude compared to the reference mineral oil Under negative polarity, inception voltage and discharge magnitude of the nanofluids and the reference mineral oil are virtually the same

Small partial discharges and their role in insulation deterioration

Abstract: It is a well known fact that PD (partial discharge) affects the lifetime and the deterioration rate of an insulation. Research work has shown that a mixture of magnitudes and frequencies of PD may appear, depending on the type of the applied voltage, its frequency, the electrode arrangement, the type of the insulation under test, and a number of other parameters, such as temperature, humidity and pressure. Various types of discharges also have been recorded, such as streamer like discharges, Townsend discharges, glow and pseudoglow discharges. A type of discharges not yet well understood is the so called SPMD (swarming partial microdischarges), which seem to appear just before breakdown. In this paper, only aspects of the latter type of PD are investigated. Some suggestions for further research regarding the SPMD are made.

Comparison of the AC barrier corona with DC positive and negative coronas and barrier discharge

Abstract: Results are presented from experimental studies of ac corona discharges between a point electrode and a dielectric-coated plate in nitrogen, argon, helium, and air in the voltage frequency range f=50 Hz–50 kHz. The characteristic features of this type of discharge are compared with the well-known features of dc positive and negative coronas and a barrier discharge between plane electrodes. It is shown that the presence of a dielectric barrier on the plane electrode significantly changes the electric characteristics and spatial structure of the corona, whereas the main phases of the discharge evolution remain unchanged as the voltage increases. With a point electrode, the breakdown voltage of the barrier corona decreases substantially as compared to the breakdown voltage of a barrier discharge with plane electrodes. This leads to softer conditions for the streamer formation in a barrier corona, which becomes more stable against spark generation.