Search results for " partial discharge"

showing 10 items of 16 documents

Space Charges and Partial Discharges Simultaneous Measurements under DC Stress

2016

In the field of HVDC, the main causes of insulation aging are due to the space charge and PD phenomena. In particular, the purpose of the present work is to verify a possibility to measure simultaneously the space charge and the PDs under DC stress in order to evaluate the correlation between both phenomena. The space charge was measured by using a modified PEA cell and PDs were measured by using a novel wireless sensor system. The space charge profile and the PD pulses carried out simultaneously have been reported and discussed.

010302 applied physicsMaterials sciencebusiness.industry020209 energyElectrical engineering02 engineering and technologyMechanicsSpace (mathematics)01 natural sciencesspace charge partial discharges DC stress HVDCStress (mechanics)Settore ING-IND/31 - Elettrotecnica0103 physical sciences0202 electrical engineering electronic engineering information engineeringbusiness
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Critical issues in the PD testing methodology for XLPE-insulated MV cables: An experimental case

2017

This paper describes some critical issues arising during the partial discharge (PD) testing of a 500m delivery length of an XLPE-insulated MV cable. At first, conventional PD measurements were performed on the whole length by using a standard acquisition system; PDs activity was detected, but the system allowed the operator to localize the PDs only on a length of 70 m. A visual inspection of this section highlighted the presence of an excoriation in the outer sheet. Aiming at a more accurate pin-pointing of the defect, more measurements were carried out in the proximity of the outer defect using a portable PD detection system. These measurements showed PDs activity, whose source was located…

010302 applied physicsOperator (computer programming)Cables Cable testing MV cables Partial Discharges Partial Discharge Measurements Partial Discharge testing PD detection Wireless PD detection XLPE-insulated cablesSection (archaeology)Computer scienceAcoustics0103 physical sciencesExcoriationPartial discharge01 natural sciences2017 IEEE Conference on Electrical Insulation and Dielectric Phenomenon (CEIDP)
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Time Evolution of Partial Discharges in a Dielectric Subjected to the DC Periodic Voltage

2022

Partial discharge (PD) detection can be considered one of the most useful tools for assessing the insulation conditions of the power apparatus in high-voltage systems. Under AC conditions, this analysis is widely employed in online and offline tests, such as type tests or commissioning, and can be carried out by applying the phase-resolved PD (PRPD) method, since the patterns can give information about the defect classification. Under DC voltages, the classic pattern recognition method cannot be performed, and the measurements show complexities related to the nature of the phenomena. For this reason, to date, a standard for PD measurements under DC does not exist. In previous papers, a new …

Direct current periodic (DCP)partial discharge (PD); direct current periodic (DCP); partial discharge measurements; HVDC; DCSettore ING-IND/31 - ElettrotecnicaControl and OptimizationHVDCRenewable Energy Sustainability and the EnvironmentEnergy Engineering and Power TechnologyElectrical and Electronic EngineeringPartial discharge (PD)Engineering (miscellaneous)DCEnergy (miscellaneous)Partial discharge measurementsEnergies; Volume 15; Issue 6; Pages: 2052
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Electrical Aging Tests on Enameled Wire Exposed to Gamma Irradiation

2011

Electrical agingIndustrial plantsMaterials sciencebusiness.industryStatorsGamma raysTestingGAMMA IRRADIATION ELECTRICAL AGINGElectrical engineeringElectrical treeingWindingThermosetsElectric brazingInsulating materialsPartial dischargesElectromechanical devicesIrradiationElectric brazing; Electromechanical devices; Gamma rays; Industrial plants; Insulating materials; Irradiation; Partial discharges; Stators; Testing; Thermosets; WindingComposite materialbusinessSettore ING-IND/19 - Impianti NucleariGamma irradiation
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A portable instrument for the location and identification of defects generating PD

2011

A portable instrument based on an antenna probe and suitable for partial discharge detection, have been characterized through both laboratory and on-site experiments carried out on coils and stator windings of ac rotating machines. The antenna probe allows the capture of electromagnetic waves in a bandwidth of 0.1–100 MHz. Pulse signals and ac supply voltage reference are obtained by means of high-pass and low-pass filters, respectively, so avoiding the need of a direct connection with the objects under test. By this way, real-time phase resolved partial discharge patterns can be derived. Results of a comparison of the diagnostic information provided by PD patterns due to conducted and irra…

EngineeringPartial Discharges; Insulation Systems; Rotating Machines; DiagnosticsRotating Machinebusiness.industryStatorAcousticsLow-pass filterPartial DischargesBandwidth (signal processing)Electrical engineeringCurrent transformerlaw.inventionInsulation SystemsInsulation SystemSettore ING-IND/31 - ElettrotecnicaRotating MachinesElectromagnetic coillawPartial dischargePartial DischargeHigh-pass filterbusinessDiagnosticsDiagnostics FPGA Partial Discharges SensorsVoltage reference
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High-Speed Machines: Typologies, Standards, and Operation under PWM Supply

2018

This paper presents an overview of the most recent state of the art in the field of high-speed electric machines fed through high-frequency converters. This type of systems is rapidly wide spreading in aeronautical and automotive applications, as well as microturbines. Each typology has its own advantages and downsides, which are analytically presented in this paper. Some types of high-speed electric machines require high-frequency voltage supply, highly stressing the dielectric materials of the winding insulation system. For this reason, in high-speed electric drives, premature failure may occur and a reduction of the total system reliability has been observed in the past years. Such issue…

High-speed machinesControl and OptimizationComputer scienceComputer Networks and CommunicationsAutomotive industryEnergy Engineering and Power Technology02 engineering and technologySettore ING-IND/32 - Convertitori Macchine E Azionamenti ElettriciHigh-frequency converters01 natural sciencesAutomotive engineeringReliability (semiconductor)Insulation systemPartial discharge0103 physical sciences0202 electrical engineering electronic engineering information engineering010302 applied physicsbusiness.industry020208 electrical & electronic engineeringConvertersInsulation ageingComputer Networks and CommunicationElectromagnetic coilHigh-speed machinePulse-width modulationbusinessHigh-frequency converterHigh-frequency converters; High-speed machines; Insulation ageing; Partial discharge; Pulse-width modulation; Control and Optimization; Computer Networks and Communications; Energy Engineering and Power TechnologyInduction motorPulse-width modulationVoltage
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Influence on PD Parameters due to Voltage Conducted Disturbances

2004

In the standard specification of ac dielectric-characteristic measurements of insulating materials, test voltage is prescribed as "approximately sinusoidal" when the highest acceptable deviation of the HV waveform, from the correct sinusoidal shape, is limited to a /spl plusmn/5% tolerance range of the crest factor value. In the field of partial discharge (PD) measurements and their statistical data processing, on which forecasts of long term behavior of components and their reliability are currently carried out, the results of elaborations depend on the voltage wave shape. In this paper, the errors in PD measurements, evaluated at industrial frequencies, due to applied voltages distorted b…

Materials scienceSteady state (electronics)Mathematical analysisPhase angleInsulation systems distorted voltage harmonics partial discharge measurements.Root mean squareSettore ING-IND/31 - ElettrotecnicaHarmonicsPartial dischargeElectronic engineeringHarmonicWaveformElectrical and Electronic EngineeringCrest factor
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Building Partial Discharge Signal Wireless Probes

2014

This chapter focuses on the evaluation of the performances of different antenna sensors suitable for Partial Discharge (PD) measurements. Monopole, triangular and spherical antennas were simulated by means of the surface method of moments. The transmitting system is modeled by a power electronic device with a fault current between two metal plates. The shape of the simulated, transmitted and received signals, has been compared to verify the sensor that provides the best fidelity among the three. The auto-correlation function and the Pearson correlation index are adopted here for the comparison. A discussion on the dynamic characteristic of the different antenna probes and their use in diffe…

PhysicsSettore ING-IND/31 - Elettrotecnicabusiness.industryPartial dischargeElectrical engineeringElectronic engineeringWirelessantenna partial discharges method of momentsbusinessSignal
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Performances of a PCB-based Loop Antenna Inductive Sensor for Partial Discharges Detection

2022

This paper presents the test results of an electrically small loop antenna sensor towards detecting the radiated magnetic field due to partial discharge (PD) activities. The loop antenna prototype was printed on an FR-4 substrate with a thickness of 1.6 mm, featuring a compact size of 20 mm times20 mm times1.7 mm. The proposed sensor, initially simulated with Ansys HFSS software, has a resonant frequency of about 100 MHz. Its detection capability for three types of partial discharges (i.e., corona, surface and internal PDs) has been evaluated. Laboratory experiments showed that the evaluated loop spiral antenna is appropriate for the detection of the three types of PDs. Indeed, the results …

Settore ING-IND/31 - ElettrotecnicaHFCT sensorInductive spiral loop; PCB-based sensor; Partial discharge detection; HFCT sensorpartial discharge detectionPCB-based sensorInductive spiral loop
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Partial discharges characteristics during load transients in an HVDC model cable

2021

The occurrence of Partial Discharges (PD) in HVAC cables is widespread considered as one of the most important concerns for the stability of the insulation. To date, the role of PD in the ageing and definitive fault of HVDC cables has been poorly investigated. This is mainly due to some practical difficulties in the performing of the measurements. Compared to the PDs occurring under AC stress, the higher inception voltages and the lower repetition rates, obtainable under DC voltage, make the exclusion of the measurement noise more difficult. This paper is focused on the study of the characteristics of the PDs occurring in an artificial defect located in proximity of the outer dielectric' su…

Settore ING-IND/31 - ElettrotecnicaHVDC cable partial discharge space charge
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