scholarly journals Partial discharges location in power transformers using piezoceramic sensors

2021 ◽  
Vol 11 (3) ◽  
pp. 1942
Author(s):  
B. Danouj ◽  
S. A. Tahan ◽  
E. David ◽  
M. Lotfi
Keyword(s):  
Partial Discharge ◽  
Spatial Localization ◽  
Flight Time ◽  
Partial Discharges ◽  
Electrical Machines ◽  
Ultrasonic Transducers ◽  
Power Transformers ◽  
Insulation System ◽  
New Generation ◽  
Published Paper

The detection and the spatial localization of partial discharges in high-voltage electrical machines are considered as an effective method in predictive maintenance that can provide valuable information on the health of the insulation system and allow to determine accurately the location of the risky insulation elements, which in turn will avoid any premature equipment’s deterioration by scheduling preventive maintenance action. After confirming in a previous published paper the efficiency of a new generation of piezoceramics sensors (high temperature ultrasonic transducers) to detect and characterize partial discharges, we are going to investigate, in this work, a second potential of this technology to locate the partial discharge sources by relying on its ability to detect acoustic signals emitted by partial discharge sources. We will present experimental results, demonstrating the effectiveness of these sensors to locate partial discharges sources and, we will also present an algorithm for calculating the partial discharge foci, based on the acoustic wave flight time.

Otkrivanje i analiza signala parcijalnih pražnjenja u energetskom transformatoru UHF metodom

2020 ◽  
Vol 22 (1-2) ◽  
pp. 96-101
Author(s):  
Đorđe Dukanac ◽  
Keyword(s):  
Detailed Analysis ◽  
Background Noise ◽  
Power Transformer ◽  
Partial Discharge ◽  
Spectral Composition ◽  
Partial Discharges ◽  
Power Transformers ◽  
Discharge Source ◽  
Useful Components

This paper presents the practical detection of partial discharge signals using a UHF sensor mounted on a power transformer and then the detailed analysis of a signal is done. The first part of the paper describes possible partial discharge sources in power transformers, UHF method and UHF sensor. In the second part of the paper, received signal at UHF sensor is considered. In order to accurately determine the magnitude of the partial discharge signal, especially if the location of the partial discharge source is far from the location of the UHF sensor, it is necessary to separate the signal from the background noise. This is only possible at intervals between individual bursts of the observed partial discharges. The spectral composition of the received signal is considered and a method for separating the present noise from the useful components of the partial discharge signal is established. The presumable main cause of partial discharges is evaluated.

scholarly journals Development of Acoustic Emission Sensor Optimized for Partial Discharge Monitoring in Power Transformers

Sensors ◽  
2019 ◽  
Vol 19 (8) ◽  
pp. 1865 ◽  
Author(s):  
Sikorski
Keyword(s):  
Acoustic Emission ◽  
Partial Discharge ◽  
Low Noise ◽  
Partial Discharges ◽  
Power Transformers ◽  
Laboratory Research ◽  
Fully Differential ◽  
Peak Sensitivity ◽  
Optimal Material ◽  
Discharge Detection

The acoustic emission (AE) technique is one of the unconventional methods of partial discharges (PD) detection. It plays a particularly important role in oil-filled power transformers diagnostics because it enables the detection and online monitoring of PDs as well as localization of their sources. The performance of this technique highly depends on measurement system configuration but mostly on the type of applied AE sensor. The paper presents, in detail, the design and manufacturing stages of an ultrasensitive AE sensor optimized for partial discharge detection in power transformers. The design assumptions were formulated based on extensive laboratory research, which allowed for the identification of dominant acoustic frequencies emitted by partial discharges in oil–paper insulation. The Krimholtz–Leedom–Matthaei (KLM) model was used to iteratively find optimal material and geometric properties of the main structures of the prototype AE sensor. It has two sensing elements with opposite polarization direction and different heights. The fully differential design allowed to obtain the desired properties of the transducer, i.e., a two-resonant (68 kHz and 90 kHz) and wide (30‒100 kHz) frequency response curve, high peak sensitivity (−61.1 dB ref. V/µbar), and low noise. The laboratory tests confirmed that the prototype transducer is characterized by ultrahigh sensitivity of partial discharge detection. Compared to commonly used commercial AE sensors, the average amplitude of PD pulses registered with the prototype sensor was a minimum of 5.2 dB higher, and a maximum of 19.8 dB higher.

Partial Discharge Detection and Location in Transformers Using UHF Techniques

2013 ◽  
pp. 487-520
Author(s):  
Martin D. Judd
Keyword(s):  
High Frequency ◽  
Partial Discharge ◽  
Gas Analysis ◽  
Power Transformers ◽  
Dissolved Gas ◽  
Insulation System ◽  
Time Difference Of Arrival ◽  
Corrective Maintenance ◽  
System A ◽  
Complete Failure

Power transformers can exhibit partial discharge (PD) activity due to incipient weaknesses in the insulation system. A certain level of PD may be tolerated because corrective maintenance requires the transformer to be removed from service. However, PD cannot simply be ignored because it can provide advance warning of potentially serious faults, which in the worst cases might lead to complete failure of the transformer. Conventional monitoring based on dissolved gas analysis does not provide information on the defect location that is necessary for a complete assessment of severity. This chapter describes the use of ultra-high frequency (UHF) sensors to detect and locate sources of PD in transformers. The UHF technique was developed for gas-insulated substations in the 1990s and its application has been extended to power transformers, where time difference of arrival methods can be used to locate PD sources. This chapter outlines the basis for UHF detection of PD, describes various UHF sensors and their installation, and provides examples of successful PD location in power transformers.

A strategy to locate partial discharges in power transformers using acoustic emission

2007 ◽  
Vol 1 (05) ◽  
pp. 596-600 ◽  
Author(s):  
Giscard Franceire Cintra Veloso ◽  
◽  
Luiz Eduardo Borges da Silva ◽  
Germano Lambert-Torres
Keyword(s):  
Acoustic Emission ◽  
Partial Discharges ◽  
Power Transformers

scholarly journals Device for online monitoring of insulation faults in high-voltage switchgears

2021 ◽  
Vol 17 (2) ◽  
pp. 155014772199928
Author(s):  
Jiajia Song ◽  
Jinbo Zhang ◽  
Xinnan Fan
Keyword(s):  
Fourier Transform ◽  
High Voltage ◽  
Online Monitoring ◽  
Pulse Current ◽  
Partial Discharge ◽  
Current Method ◽  
Capacitive Sensor ◽  
Accurate Diagnosis ◽  
Partial Discharges ◽  
Urgent Problem

Partial discharges are the major cause of deterioration in the insulation characteristics of switchgears. Therefore, timely detection of partial discharge in switchgear and potential insulation faults is an urgent problem that needs to be addressed in the power supervision industry. In this study, a device was proposed for online monitoring of high-voltage switchgears based on pulse current method and ozone (O3) detection. The pulse current method obtains the PD signal by monitoring the phase holes on the switch indicator. Occurrence of a partial discharge in a certain phase leads to the production of a discharge pulse, which can be coupled out by a capacitive sensor. The current spectrum and the O3 produced by partial discharge were processed via fast Fourier transform for accurate diagnosis of the occurrence of partial discharge and its severity in switchgears. The proposed method allows for convenient acquisition of the partial discharge signal, simple installation of the device, and realization with inexpensive sensors.

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