Location of partial discharge sources in power transformers based on advanced auscultatory technique

Sikorski, Wojciech; Siodła, Krzysztof; Morańda, H.; Ziomek, W.

doi:10.1109/tdei.2012.6396952

Cited by 44 publications

(20 citation statements)

References 6 publications

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“…The mounting places are usually chosen on the basis of results obtained with the auscultatory technique (PD activity regions can be easily identified by taking acoustic measurements in a number of places on the transformer tank) [7]. To reduce the influence of external electromagnetic and acoustic interference, the piezoelectric transducer and preamplifier circuit (40 dB) are mounted in a combined metal housing equipped with magnetic holders and passive vibration absorbers.…”

Section: Prototype Online Partial Discharge Monitoring System For Powmentioning

confidence: 99%

Moisture Migration in an Oil-Paper Insulation System in Relation to Online Partial Discharge Monitoring of Power Transformers

2016

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Most power transformers operating in a power system possess oil-paper insulation. A serious defect of this type of insulation, which is associated with long operation time, is an increase in the moisture content. Moisture introduces a number of threats to proper operation of the transformer, e.g., ignition of partial discharges (PDs). Due to the varying temperature of the insulation system during the unit's normal operation, a dynamic change (migration of water) takes place, precipitating the oil-paper system from a state of hydrodynamic equilibrium. This causes the PDs to be variable in time, and they may intensify or extinguish. Studies on model objects have been conducted to determine the conditions (temperature, humidity, time) that will have an impact on the ignition and intensity of the observed phenomenon of PDs. The conclusions of this study will have a practical application in the evaluation of measurements conducted in the field, especially in relation to the registration of an online PD monitoring system.

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Section: Prototype Online Partial Discharge Monitoring System For Powmentioning

confidence: 99%

Moisture Migration in an Oil-Paper Insulation System in Relation to Online Partial Discharge Monitoring of Power Transformers

2016

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“…The electromagnetic radiation of the PD is measured in terms of millivolt (mV) When electrical or UHF PD measurements record PD activity, a three dimensional localization of PD is the next step for risk evaluation. This can be performed based on arrival time measurement of acoustical PD signals [9] using piezo-electric sensors mounted on transformer tank walls [10]. However, acoustic PD signals are affected by distortion within the tank from the windings, core and supporting structures in the transit path.…”

Section: Calibration Of Partial Discharge Measurementsmentioning

confidence: 99%

Diagnostic Measurements for Power Transformers

et al. 2016

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Abstract:With the increasing age of the primary equipment of the electrical grids there exists also an increasing need to know its internal condition. For this purpose, off-and online diagnostic methods and systems for power transformers have been developed in recent years. Online monitoring is used continuously during operation and offers possibilities to record the relevant stresses which can affect the lifetime. The evaluation of these data offers the possibility of detecting oncoming faults early. In comparison to this, offline methods require disconnecting the transformer from the electrical grid and are used during planned inspections or when the transformer is already failure suspicious. This contribution presents the status and current trends of different diagnostic techniques of power transformers. It provides significant tutorial elements, backed up by case studies, results and some analysis. The broadness and improvements of the presented diagnostic techniques show that the power transformer is not anymore a black box that does not allow a view into its internal condition. Reliable and accurate condition assessment is possible leading to more efficient maintenance strategies.

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“…Equipment used for the measurement cannot have any impact on the recording signals. PD source can be than localized under understanding that the information about sectional winding transfer functions is available [3][4][5][6][7] shown in Fig.I. This SWTF can be calculated based on design data.…”

Section: New Concept Of the Pd Localization On Dry-type Transformentioning

confidence: 99%

Partial discharge localization on dry-type transformers

Szczechowski

Siodła

2014

2014 ICHVE International Conference on High Voltage Engineering and Application

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In this paper an electrical partial discharge (PD) localization technique for a dry type power transformer is presented. The method has been tested in the laboratory on real transformer coil as well as on a transformer in a test bay.Calibration signal is injected through a plate sensor placed along the winding on the surface of the transformer coil in different positions, thus PD signals can be measured at both coil terminal sites using digitizer. Measured PD signal during test can be then evaluate and compared with calculated transfer function. The described technique enables not only localization of the PD source also determination of the apparent charge. This evaluation can be more accurate than conventional PD measurements by use of quadruple and coupling capacitor calibration and can be used during manufacturing process as well as diagnostic in field.

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Location of partial discharge sources in power transformers based on advanced auscultatory technique

Cited by 44 publications

References 6 publications

Moisture Migration in an Oil-Paper Insulation System in Relation to Online Partial Discharge Monitoring of Power Transformers

Moisture Migration in an Oil-Paper Insulation System in Relation to Online Partial Discharge Monitoring of Power Transformers

Diagnostic Measurements for Power Transformers

Partial discharge localization on dry-type transformers

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