Vibration Sparking and Slot Discharge in Stator Windings

Stone, G.C.; Maughan, Clyde V.

doi:10.1109/elinsl.2008.4570298

Cited by 8 publications

(3 citation statements)

References 6 publications

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“…Slot discharges are known as the common failure mechanism of stator winding insutation [25] and manifest when the protective coating of the stator slots becomes compromised, typically as a result of vibrations, displacements, and friction associated with the movement of stator bars. This damage often initiates a gradual erosion process over time, leading to the deterioration of insulation integrity [3,10]. It is noteworthy that the time interval between the initiation of these discharges and the eventual breakdown of the insulation material tends to be relatively short.…”

Section: Theoretical Reviewmentioning

confidence: 99%

“…PD monitoring relies on techniques that enable the identification of issues in these machines, contributing to preventive and predictive maintenance. According to [3], there are four types of PDs that can occur in high-voltage electrical equipment: internal discharges, slot discharges, discharges in the end winding, and arcing and sparking.…”

Section: Introductionmentioning

confidence: 99%

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Ozone Transport in 311 MVA Hydrogenerator: Computational Fluid Dynamics Modelling of Three-Dimensional Electric Machine

de Oliveira,

Girotto,

de Alcantara

et al. 2023

Energies

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In this paper, a three-dimensional turbulent fluid dynamics numerical model of a 311 MVA full hydroelectric power plant unit is made, using the finite element method, to study and understand the ozone transport mechanisms inside the enclosured electric machine structure. In the real world, ozone is produced by partial discharges related to faults on stator bars. In order to analyse ozone transport from localised sources, a 3D fluid dynamic model of a complete hydrogenerator in operation is developed and presented for the first time. The model has a high level of geometric detail. Furthermore, a new proposal to simplify the modelling of radiators is implemented and validated. The modelled structure is based on a Campos Novos hydrogenerator electric machine and it consists of 378 coil-type stator bars made of copper covered by mica and, more externally, by a semiconductor coating layer. Other parts are also represented, including the stator core and air directors made of stainless steel, copper radiators, the rotor with its epoxy surface, and the concrete floor and concrete external walls. In the fluid dynamics model, a finite element mesh was designed to represent the air regions inside the hydrogenerator and the material surfaces that react with ozone (with their respective reaction rates), where the airflow and ozone transport are modelled using the Navier–Stokes equations and the mass conservation law. Partial discharge sources are represented by ozone sources with prismatic shapes, placed on surfaces of stator bars. Ozone concentrations have been calculated inside and around the generator machine. The rotor radius is 3.8075 m and its rotation frequency is 200 RPM. Radial air velocity due to interpole ventilation is also considered (2.2 m/s, as experimentally verified in loco. The radial velocity in the vicinity of the radiators is 3 m/s. It has been concluded that the ozone transport profile is influenced by the source positioning on the stator bars in such a way that source pinpointing is possible and it depends on determining the local and global maxima areas of ozone concentration at the radiators.

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Section: Theoretical Reviewmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Ozone Transport in 311 MVA Hydrogenerator: Computational Fluid Dynamics Modelling of Three-Dimensional Electric Machine

de Oliveira,

Girotto,

de Alcantara

et al. 2023

Energies

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“…In recent years, with the continuous improvement of the partial discharge detection equipment and methods, there are numerous studies at home and abroad about the occurrence of slot discharge and impact of aging factors on slot discharge. For example, Canadian Claude Hudon studied the development of slot discharge at different humidity [6] ; Stone studied the effect of vibration on the discharge [8] . However, there are scare studies on the slot discharge mechanism at different temperatures and the partial discharge parameters.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Temperature on Slot Discharge for High Voltage Stator Windings

Ding-qiang¹,

Wang²

2017

dteees

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During the operation of HV (high voltage) motor, the abrasion of stator windings because of vibration caused by electromagnetic force will give rise to slot discharge. Furthermore, the superheat induced by overcurrent or poor heat dissipation will aggravate the slot discharge. To understand the effect of different temperatures on slot discharge, two laboratory experiments, under different temperatures, were carried out to simulate the slot discharge for 120h. The experiment results indicate that the temperature greatly promotes the development of the slot discharge.

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