Influence of Voltage Harmonics on Partial Discharge Diagnostics in Electric Motors Fed by Variable-Frequency Drives

Hassan, Waqar; Mahmood, Farhan; Andreotti, Amedeo; Pagano, Mario; Ahmad, Farooq

doi:10.1109/tie.2021.3134085

Cited by 15 publications

(10 citation statements)

References 25 publications

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“…Analysis of existing technical solutions and theoretical studies of the braking modes of a DC electric drive with a seriesexcitation motor was conducted as well [16]. There are formulated problems that prevent the development of control systems for a variable-speed DC electric drive with seriesexcited motors in the dynamic braking mode.…”

Section: Eksploatacja I Niezawodnosc -Maintenance and Reliabilitymentioning

confidence: 99%

Variable-speed drive with series-excited motors in dynamic braking mode

Kenessova¹,

Kaverin²,

Tatkeyeva³

2023

Eksploatacja i Niezawodność – Maintenance and Reliability

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Variable-speed DC drives with series-excited motors are widely used in the mining industry, transport and lifting equipment. The purpose of the study is to determine the dynamic characteristics of a variable direct current (DC) drive with a series-excited motor in the dynamic braking mode. In the article, there have been developed schematic diagrams of the power section that ensure stable braking of a variable-speed electric drive with a series-excited motor. The requirements for the braking mode have been developed. The studies have been carried out for a saturated and unsaturated magnetic circuit of an electric motor. The scientific novelty of the work consists in determining the zone of stable operation of the dynamic braking mode. As a result, there has been proposed technical implementation of the power section of a variable-speed electric drive with a series-excited motor that ensures stable braking. A special place in the study is the development of two models of an electric motor with subsequent excitation taking into account the saturation of the magnetic circuit - mathematical and simulation. Thus, the article has not only theoretical but also visual and practical significance in the context of already conducted studies on the subject. Options for the technical implementation of the braking regime were also considered in the course of the sequential implementation of the planned stages of the study.

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Section: Eksploatacja I Niezawodnosc -Maintenance and Reliabilitymentioning

confidence: 99%

Variable-speed drive with series-excited motors in dynamic braking mode

Kenessova¹,

Kaverin²,

Tatkeyeva³

2023

Eksploatacja i Niezawodność – Maintenance and Reliability

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“…During the operation of a motor, due to the commutation process using PWM, some voltage pulses can be confused with PD activities if the monitoring system is not calibrated considering this factor and if it does not have additional filtering with an adjusted frequency band [90]. In addition, it should also be taken into account that the voltage harmonics caused by inverters may amplify PD signals, as shown in [91], where it was found that the greater the Total Harmonic Distortion (THD), the greater the number of discharge pulses and, in some cases, the greater the PD amplitude. Another factor that influences the PD activity is the applied supply voltage waveform, since from [92], it is possible to verify that three different PD patterns are generated for three supply waveforms coming from inverters of two levels, five levels, and sinusoidal voltage.…”

Section: Influence Of the Drive System On The Pd Readingmentioning

confidence: 99%

Partial Discharges Monitoring for Electric Machines Diagnosis: A Review

et al. 2022

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Online monitoring of Partial Discharges (PDs) in rotating electrical machines is an useful tool for machine prognosis, as it presents reduced costs compared to intrusive inspections and is associated with relevant problems. Although this monitoring method has been developed for almost 50 years, the recent advancements in processes automation and signal processing techniques allow improvements that are still being studied by academic and industrial researchers. To analyze the current context of PDs monitoring, this article presents a literature review based on concepts of PDs in rotating machines, data acquisition techniques, state-of-the art commercial equipment, and recent methodologies for detection and pattern recognition of PDs. The challenges identified in the literature that motivate the development of more reliable and robust PD monitoring systems are presented and discussed.

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“…However, when VFD-fed EMs are in operation, the harmonic components in the applied voltage waveform may develop, which could lead to premature insulation failure of the stator winding over time [4]. Therefore, online condition monitoring of VFD-fed EMs is essential to detect any preemptive winding insulation failure and plan regular maintenance activities [5,6].…”

Section: Introductionmentioning

confidence: 99%

“…In laboratory-based studies, PD measurements are typically conducted using a sinusoidal waveform of the applied voltage. However, in field operations, variable speed operation of VFD-fed EM can produce several harmonic components, resulting in a distorted voltage waveform that can significantly affect PD activity in the winding insulation [5]. Therefore, a better understanding of harmonic distortion in the applied voltage waveform is essential for accurately assessing the severity of PD and establishing an effective maintenance scheduling strategy for stator insulation in EMs.…”

Section: Introductionmentioning

confidence: 99%

Close accord on partial discharge diagnosis during voltage harmonics in electric motors fed by variable frequency drives

Hassan,

Akmal,

Hussain

et al. 2023

IET Generation Trans & Dist

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Partial discharge (PD) diagnostics test is a reliable solution for estimating insulation health conditions in power system components. During laboratory PD diagnostics, the effect of harmonic components in the voltage waveform generated by variable frequency drives (VFD) fed electric motors (EMs) is often overlooked. As VFD‐fed EMs operate at low speeds, the harmonic concentration in the voltage increases. It has been found that PD activity in VFD‐fed EM is significantly affected by the addition of harmonic components in the voltage, thus making it necessary to consider their impact when performing true PD diagnostics. This paper investigates the influence of voltage harmonic distortion produced in VFD‐fed EM on PD severity and the subsequent insulation degradation. Eight VFD‐fed EM are used to study the PD behaviour under different levels of harmonic pollution. The PD characteristics, such as inception voltage, pulse repetition rate, accumulated apparent charge, average discharge current, discharge power, and quadratic rate, are determined. Using probability distribution functions, PD activity and severity at various voltage harmonic levels are estimated. The proposed technique can be used to plan the maintenance activities that ensure the reliability for industrial applications dealing with the voltage harmonic distortion.

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Influence of Voltage Harmonics on Partial Discharge Diagnostics in Electric Motors Fed by Variable-Frequency Drives

Cited by 15 publications

References 25 publications

Variable-speed drive with series-excited motors in dynamic braking mode

Variable-speed drive with series-excited motors in dynamic braking mode

Partial Discharges Monitoring for Electric Machines Diagnosis: A Review

Close accord on partial discharge diagnosis during voltage harmonics in electric motors fed by variable frequency drives

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