Measurement and evaluation of partial discharge inception voltage for enameled rectangular wires under AC voltage

Wakimoto, Toru; Kojima, H.; Hayakawa, Naoki

doi:10.1109/tdei.2016.005645

Cited by 25 publications

(17 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Another parameter that can influence the electric field in the air gap is the surface conductivity of the insulation, where its increment consequent to thermal ageing can decrease the electric field in the air gap or vice versa [16]. Indeed, when surface conductivity decreases, the charge depletion time constant decreases.…”

Section: E Capacitance Variations As a Function Of Excitation Rise Ti...mentioning

confidence: 99%

A Contribution to Thermal Ageing Assessment of Glass Fibre Insulated Wire Based on Partial Discharges Activity

2022

View full text Add to dashboard Cite

This paper aims to evaluate a Type-II insulated wire (i.e., Glass fibre insulated wire) as a function of thermal ageing time based on partial discharges (PD) activity. Partial discharge inception voltage (PDIV), partial discharge extinction voltage (PDEV), and repetitive partial discharge inception voltage (RPDIV) measurements have been performed on both unaged and thermally aged specimens. Each specimen modelled the turn-to-turn insulation; hence it was made by a pair of Glass fibre wires wrapped in PTFE tape for a mechanical purpose. The PD tests have been carried out under positive and negative unipolar square waveform excitations using different rise times: 80, 400 and 800 ns. The trend of PD quantities vs exposure time demonstrates that the effect of space charge accumulation under unipolar excitation must be taken into account when unaged and thermally aged specimens are compared. Results revealed that although sometimes thermally aged samples might show a temporary superiority in the short run, unaged ones always present a better performance after space charge accumulation, as expected. Following the statistic postprocessing of the collected data, shape/slope parameters of the Weibull distribution relevant to PDIV can be used as an ageing indicator for Glass fibre insulated wire. Finally, the permittivity evaluation vs thermal and electrical stresses have been performed, relying on the measured capacitance of each specimen just after every PD test. Such analysis revealed that thermal ageing increases permittivity in the long run. However, electrical stress has different impacts on permittivity depending on the rise time, polarity, and magnitude of the applied voltage.

show abstract

Section: E Capacitance Variations As a Function Of Excitation Rise Ti...mentioning

confidence: 99%

A Contribution to Thermal Ageing Assessment of Glass Fibre Insulated Wire Based on Partial Discharges Activity

2022

View full text Add to dashboard Cite

show abstract

“…To pursue high-performance EMs, understanding the physics of partial discharge is necessary instead of adopting the empirical enhancement factor. Many works dedicate to investigate the influence factors on PDIV or RPDIV of turn/turn insulation [54,62,120,123,[138][139][140][141][142][143][144][145][146][147][148][149][150][151][152][153] through experiments. A typical experiment setup for PDIV investigation is presented in Figure 11.…”

Section: Experiment-based Studies On Pdmentioning

confidence: 99%

“…The same method can be found in [134,152] where both temperature and pressure are considered. Humidity can also influence the PDIV, and the investigation on twisted pairs can be found both under ac voltage [121,140,145,156] and surge voltage [140]. No general tendency can be concluded since the effect of humidity may both depend on temperature [156] and voltage type [140].…”

Section: Effect Of Ambient Conditionsmentioning

confidence: 99%

“…The impulsive voltage caused by the inverter may influence PDIV although t is also not highlighted in the standards. Typically, a surge voltage is characterized time, repetition frequency, and duty cycle and a couple of work studying the influ PDIV can be found for each topic: rise time [62,130,138,148], frequency [138,[143][144][145][146][147][148][149]153], and duty cycle [147,148]. To account for the potential insulation challeng by the WBG device, some papers have conducted the investigation based on th device.…”

Section: Effect Of Insulation Thickness and Conductor Diametermentioning

confidence: 99%

See 1 more Smart Citation

Reliability-Oriented Design of Inverter-Fed Low-Voltage Electrical Machines: Potential Solutions

Giangrande

Madonna³

et al. 2021

Energies

View full text Add to dashboard Cite

Transportation electrification has kept pushing low-voltage inverter-fed electrical machines to reach a higher power density while guaranteeing appropriate reliability levels. Methods commonly adopted to boost power density (i.e., higher current density, faster switching frequency for high speed, and higher DC link voltage) will unavoidably increase the stress to the insulation system which leads to a decrease in reliability. Thus, a trade-off is required between power density and reliability during the machine design. Currently, it is a challenging task to evaluate reliability during the design stage and the over-engineering approach is applied. To solve this problem, physics of failure (POF) is introduced and its feasibility for electrical machine (EM) design is discussed through reviewing past work on insulation investigation. Then the special focus is given to partial discharge (PD) whose occurrence means the end-of-life of low-voltage EMs. The PD-free design methodology based on understanding the physics of PD is presented to substitute the over-engineering approach. Finally, a comprehensive reliability-oriented design (ROD) approach adopting POF and PD-free design strategy is given as a potential solution for reliable and high-performance inverter-fed low-voltage EM design.

show abstract

“…This pre-conditioning process is very important as the momentary high thermal exposure removes any volatile moisture and substances from the layer of dielectric insulation. These impurities can significantly influence the measurement of the dielectric properties [42] that can result in a collection of data with high variability. For this reason, the 'unaged' term in the presented study is referred to a pre-conditioned specimen, since the specimen is still unaged (i.e.…”

Section: A Pre-conditioning Processmentioning

confidence: 99%

The Role of Neural Networks in Predicting the Thermal Life of Electrical Machines

et al. 2020

View full text Add to dashboard Cite

For a continuous mode of operation, insulating material in an electrical machine is subject to constant thermal, electrical, mechanical and environmental stresses where thermal stress is a major cause of gradual insulation deterioration, which leads to ultimate winding failure. To guarantee a satisfactory lifetime, electrical machines are designed to operate winding temperatures well below their thermal class, which results in an oversized design. Standard methods for thermal lifetime evaluation of electrical machines are based on accelerated aging tests that require several months of testing. This paper proposes an alternative approach relying on a supervised neural network that significantly shortens the time demanded by accelerated aging tests for thermal lifetime evaluation of electrical machines. The supervised neural network is based on a feedforward neural network trained with Bayesian Regularisation Backpropagation (BRP) algorithm. The network predicts the wire insulation resistance with respect to its aging time at aging temperatures of 250 • C, 270 • C and 290 • C, which reveals a good match of prediction outcomes against the experimental findings. The mean time-to-failure at each aging temperature is extracted using the Weibull probability plot in order to compare the Arrhenius curves for both conventional and proposed method and a relative error of 0.125% is achieved in terms of their temperature indexes. In addition, the analysis shows a time saving of 1680 hours (57% time saved of experimental test procedure) when the thermal life of the insulating material is predicted using BRP neural network. INDEX TERMS Neural network, aging time, thermal life of insulation, accelerated lifetime test.

show abstract

Measurement and evaluation of partial discharge inception voltage for enameled rectangular wires under AC voltage

Cited by 25 publications

References 17 publications

A Contribution to Thermal Ageing Assessment of Glass Fibre Insulated Wire Based on Partial Discharges Activity

A Contribution to Thermal Ageing Assessment of Glass Fibre Insulated Wire Based on Partial Discharges Activity

Reliability-Oriented Design of Inverter-Fed Low-Voltage Electrical Machines: Potential Solutions

The Role of Neural Networks in Predicting the Thermal Life of Electrical Machines

Contact Info

Product

Resources

About