Investigation of Corona Partial Discharge Characteristics Under Variable Frequency and Air Pressure

Esfahani, Ali Nasr; Shahabi, Saeed; Stone, G.C.; Kordi, Behzad

doi:10.1109/eic.2018.8481047

Cited by 30 publications

(25 citation statements)

References 5 publications

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“…Samples with an additional coating layer as well as single-coated and uncoated samples were tested to evaluate the effect of an additional coating layer on the ability of a PCB to withstand high voltages. Because PD is more likely to happen in low-air-pressure conditions [28], some of the samples were examined in a low-air-pressure test condition as well. As shown in Figure 10, a sealed chamber was used to provide the low air pressure environment at 33 kPa (sea-level air pressure is 101 kPa).…”

Section: Breakdown Voltage Testmentioning

confidence: 99%

Electrical Insulation of Conformally Coated Printed Circuit Boards: An Overview and a Study of the Influence of Pollution

Zeynali

Bridges

Kordi

2021

IEEE Electr. Insul. Mag.

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Section: Breakdown Voltage Testmentioning

confidence: 99%

Electrical Insulation of Conformally Coated Printed Circuit Boards: An Overview and a Study of the Influence of Pollution

Zeynali

Bridges

Kordi

2021

IEEE Electr. Insul. Mag.

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“…However, there are couple of factors that can increase the possibility of PD phenomenon and significantly decrease the life of insulation system. These factors include low air pressure at high altitude [37], high dv/dt pulses at the machine terminals (which are a combination of PWM pulses and reflected waves due to cable and motor terminal impedance mismatch) [38]- [39] [40], and high operating temperature [41]. In the IEC 600034-27-1 standard, different types of PDs such as slot discharge, surface discharge, etc.…”

Section: A Aerospacementioning

confidence: 99%

Survey of Insulation Systems in Electrical Machines

Hemmati

El-Refaie

2019

2019 IEEE International Electric Machines &Amp; Drives Conference (IEMDC)

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Insulating materials and insulation systems design have been gaining more attentions as more electrical machines tend to operate in harsher environments for various applications. Harsh environments include high temperature, humidity, erosion, low air pressure, etc. This paper discusses recent advances in insulation systems for electrical machines. Insulation tests as well as test standards that have been used to evaluate insulation systems and detect insulation failures will be discussed. Insulating materials used for a wide range of industrial applications such as wind turbine generators, aerospace hybrid/electric powertrain, and hydro generators have been summarized. For the emerging high-altitude, highvoltage aerospace applications, partial discharge and its impact on insulation systems will be discussed. Finally, polymer nanocomposite materials with excellent thermal conductivity and dielectric strength are highlighted as an outlook. SECTION I. Introduction Due to the continued growth of renewable energys, the number of electrical machines used worldwide has significantly increased. Insulation system is a very critical component of electrical machines. Insulation breakdown can lead to failures, which eventually result unpredicted downtime and negative financial impacts and in some applications can be a safety hazard. For some specific industries where uninterruptible operation is required, the unpredicted downtime is unacceptable. The unpredicted downtime for an offshore oil plant would be $25,000/h [1]. The dielectric strength of electrical insulation materials has been gradually improved over the years. By introducing new materials in the past 20 years for instance, the dielectric strength of ground-wall insulation nearly doubled [2]. Electrical, mechanical, thermal, and ambient stresses can cause insulation degradation which consequently leads to insulation failure [3], [4]. Insulation failure causes short circuits in the stator winding and consequently high currents could pass through the defected stator winding [5]. A survey on 1141 induction motors with power ratings above 200 hp shows that around 30% of motor failures are due to insulation failures [6]. With advances in sensors, digital signal processing, diagnosis methods and test standards, insulation failures can be detected [7], [8]. Through online estimation of material degradation and lifetime in early stages, insulation systems of electric machines can be protected from further aging while unpredicted downtime could be avoided through scheduled maintenance. Even though insulation system is a passive component in an electrical machine which does not produce torque, insulation build/thickness (which represents the key thermal resistance in electrical machine)can have significant impact on the machine cooling and hence electrical loading and torque production. There have been several efforts to minimize insulation thickness for design compactness, low manufacturing cost and high efficiency [3]. The two main functions of insulation systems in electr...

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“…Electrical distribution systems of next generation aircrafts are exposed to greater exigencies due to the increasing complexity and electrical power demanded, jointly with the severe environments at which the components are exposed. The increasing demand for electrical power distribution in aeronautics has led to an increase in the operating voltages in order to maintain the current levels and avoid using heavier wires, thus increasing the electric stress on insulation systems [1,2] in addition to the effects of extreme environmental conditions, i.e., pressure and temperature.…”

Section: Introductionmentioning

confidence: 99%

“…For example, the aircraft industry is developing power systems operating at higher voltage levels, i.e., with bus voltages in the range of 1.5 kV DC up to 4.5 kV DC, thus giving rise to harmful effects, such as corona and arc tracking effects [4]. The increased voltage levels, jointly with the reduced pressure, promote partial discharge inception conditions in insulation systems [2]. Therefore, partial discharge risk must be limited while dealing with systems that are as light and compact as possible [1].…”

Section: Introductionmentioning

confidence: 99%

Experimental Study of Visual Corona under Aeronautic Pressure Conditions Using Low-Cost Imaging Sensors

Riba

Gómez-Pau

Moreno-Eguilaz

2020

Sensors

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Visual corona tests have been broadly applied for identifying the critical corona points of diverse high-voltage devices, although other approaches based on partial discharge or radio interference voltage measurements are also widely applied to detect corona activity. Nevertheless, these two techniques must be applied in screened laboratories, which are scarce and expensive, require sophisticated instrumentation, and typically do not allow location of the discharge points. This paper describes the detection of the visual corona and location of the critical corona points of a sphere-plane gap configurations under different pressure conditions ranging from 100 to 20 kPa, covering the pressures typically found in aeronautic environments. The corona detection is made with a low-cost CMOS imaging sensor from both the visible and ultraviolet (UV) spectrum, which allows detection of the discharge points and their locations, thus significantly reducing the complexity and costs of the instrumentation required while preserving the sensitivity and accuracy of the measurements. The approach proposed in this paper can be applied in aerospace applications to prevent the arc tracking phenomenon, which can lead to catastrophic consequences since there is not a clear protection solution, due to the low levels of leakage current involved in the pre-arc phenomenon.

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Investigation of Corona Partial Discharge Characteristics Under Variable Frequency and Air Pressure

Cited by 30 publications

References 5 publications

Electrical Insulation of Conformally Coated Printed Circuit Boards: An Overview and a Study of the Influence of Pollution

Electrical Insulation of Conformally Coated Printed Circuit Boards: An Overview and a Study of the Influence of Pollution

Survey of Insulation Systems in Electrical Machines

Experimental Study of Visual Corona under Aeronautic Pressure Conditions Using Low-Cost Imaging Sensors

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