Fast transients and their effect on transformer insulation: simulation and measurements

Herdt, H De; Declercq, Jan; SeIs, T.; Craenenbroeck, Thierry Van; Dommelen, Daniel Van

doi:10.1049/cp:20010678

Cited by 4 publications

(4 citation statements)

References 6 publications

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“…A mounting recognition of transient impacts on power systems, in a high-frequency context, in particular, has awakened in industrial power quality phenomena in the recent past. Due to some critical reasons explained in [44], the limited interest in high-frequency transients in industrial low and medium voltage power systems keeps the danger buried and harasses the electrical machines further. e spaces occurring in the swollen cables' insulation are the ultimate impact yielded due to high amplitude transients, resulting from corona discharges.…”

Section: Discussionmentioning

confidence: 99%

Signatures of Transient Overvoltages in Low Voltage Power Systems in Tea Factories and Their Implications on Insulation Deterioration and Allied Power Quality Issues

Pannila

Edirisinghe

2021

Journal of Electrical and Computer Engineering

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Electrical equipment and supply cables demand a better quality of supply, with the recent advancements in integrated sensitive solid-state controls. Divergently, proliferated heavy inductive motors and some performance additions based on power electronics have introduced power quality issues to the network. Thus, this study mainly investigates the impact of switching transients generated by electromechanical machines in industrial power systems on insulation deterioration while taking transient overvoltages due to capacitor bank switching also to support. Transients with a high rate of rise are likely to catalyze the degradation of the insulation quality and break down the insulating material through ionization. These steeply passing overvoltage stresses let partial discharges ensue, which can attack the insulation over long service. To unveil this danger, 314 common-mode transient waveforms were measured in the electrical machines of five tea factories in Sri Lanka, in a 50 ms measurement window, taken in 55 measuring attempts. Most of the transients observed are in the form of a damped oscillatory waveform tailed by fast exponential collapse. That correlates to insulation degradation having a very steep rise as 30.04 V/ns, the highest at the withering section. When machines are heavily loaded, situations tend to generate transients with high amplitudes. There were transient bursts that spread as 426.3 ms, while 14 ns fast rise times were recorded from withering motors. Unlike electrical resonance and power-frequency overvoltages, electromagnetic switching transients last even less than 100 ms. To underline this, an analysis of the frequency domain of transients was also presented, which proves high density of high-frequency components reaching 107 kHz range. Accepting the fact that frequency and amplitude are always under the influences of innumerable dynamics, the observational evidence of the study endorses that electrical stress built by the transient nature of the factories reduces the life expectancy of electrical insulation.

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Section: Discussionmentioning

confidence: 99%

Signatures of Transient Overvoltages in Low Voltage Power Systems in Tea Factories and Their Implications on Insulation Deterioration and Allied Power Quality Issues

Pannila

Edirisinghe

2021

Journal of Electrical and Computer Engineering

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“…A detailed high-frequency transformer model is needed to determine the voltage levels across transformer insulation during the specific external transients. Although high-frequency general models are accurate and precise, they are often too large to incorporate into an overall power system model [22].…”

Section: Characteristics Of Equipment and Components For Trvmentioning

confidence: 99%

A Comprehensive Review on Transient Recovery Voltage in Power Systems: Models, Standardizations and Analysis

Lazzari,

de Morais,

Ramos

et al. 2023

Energies

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Electrical power systems are exposed to transient disturbances that change the voltage and current signals of the network, which can interrupt power and damage equipment. In high-frequency phenomena, it is essential to study the transient recovery voltage (TRV) to ensure the electrical insulation limits of circuit breakers are not violated, thus leading to a safe and reliable operation. Adequate models are crucial to achieving satisfactory results in the studies, according to the range of frequency of the transient being evaluated. This paper presents a comprehensive literature review of methods and models for studying electromagnetic transients, focusing on TRV requests imposed on circuit breakers, in addition to fault-clearing simulations on real system modeling. The analyses are fundamental both for the evaluation of the amplitude of the voltage signal and for its rate of rise. We also compare the reviewed models and techniques to provide a handy resource for researchers.

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“…The protection of transformers and other system equipments against transient overvoltages resulting from lighting or other causes is an important consideration in power system design for insulation co-ordination in transmission and substation equipments [1]. It is necessary to accurately predict the lightening surge overvoltages that occur in power systems [2]. The magnitude and waveform of these overvoltages arriving at the terminating transformer are greatly affected by using of the length of a cable connecting the transmission line to the transformer [3].…”

Section: Introductionmentioning

confidence: 99%

“…It is necessary to accurately predict the lightening surge overvoltages that occur in power systems [2]. The magnitude and waveform of these overvoltages arriving at the terminating transformer are greatly affected by using of the length of a cable connecting the transmission line to the transformer [3]. The striking of lightening on transmission line causes distorted overvoltage and current on a transformer terminated at a transmission line [4].…”

Section: Introductionmentioning

confidence: 99%

Transformer hot spot temperature assessment terminated at transmission line through a cable under lightning impulses

2009

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This paper deals with the effect of distorted overvoltage and current on a transformer terminated at a transmission line through a cable that caused by striking of lightening on transmission line. Also the effect of harmonic current on transformer losses that cause overheating and aging of insulation is discussed. And then the hot spot and top oil temperature under the harmonic conditions using thermal model will be predicted. The thermal model is introduced by heat transfer principles including oil-to-air heat transfer and winding to oil heat transfer. And also the increase of harmonic current decline transformer life time. In addition, transient simulation is performed using EMTP software will show the longer cable the less amplitude of distorted operating conditions on the terminal of the transformer.

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Fast transients and their effect on transformer insulation: simulation and measurements

Cited by 4 publications

References 6 publications

Signatures of Transient Overvoltages in Low Voltage Power Systems in Tea Factories and Their Implications on Insulation Deterioration and Allied Power Quality Issues

Signatures of Transient Overvoltages in Low Voltage Power Systems in Tea Factories and Their Implications on Insulation Deterioration and Allied Power Quality Issues

A Comprehensive Review on Transient Recovery Voltage in Power Systems: Models, Standardizations and Analysis

Transformer hot spot temperature assessment terminated at transmission line through a cable under lightning impulses

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