UHF PD measurements on power transformers-advantages and limitations

Jahangir, Hamid; Akbari, Asghar; Werle, Peter; Szczechowski, Janusz

doi:10.1109/tdei.2017.006149

Cited by 51 publications

(32 citation statements)

References 12 publications

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“…Especially, the self-constructed orthogonal inductive antenna showed in combination with the applied filter a high sensitivity to PD events and low sensitivity for distortion. The investigation showed that the UHF or VHF frequency range known from the measurements in power transformers [10,11] might be inadequate to detect PD in solid-air insulation systems. Neither frequency ranges offered the possibility to distinguish clearly between desired PD signals and disturbance.…”

Section: Discussionmentioning

confidence: 99%

Detection Technique of Partial Discharges at Impulse Voltage with Appropriate Filter Settings for Signal Separation

2019

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Due to the increased utilization of electric converters feeding rotating high voltage motors, their insulation is subject to transient impulse and high frequency oscillating voltages. In corresponding life time experiments with repetitive oscillating impulse voltage at winding insulation samples, higher life time coefficients were observed than known from previous investigations and operational experience. In order to understand the discharge and aging phenomena, the purpose of this work is the secure detection of partial discharges in solid and solid–air insulation types for transient impulse voltage stress by applying an adequate partial discharge (PD) measurement technique to future life time experiments. It is shown that partial discharges under impulsive voltages can be detected with conventional measuring equipment using broadband shunts, as well as inductive antennas. It becomes apparent that a precise voltage source, a precise shunt, as well as a high resolution oscilloscope are mandatory for reliable current measurement results. As a part of the analysis of the measurement data, it is shown that partial discharges can be distinguished from the displacement current caused by impulse voltages in a capacitive insulation material, as well as noise and disturbance from the measurement environment. As a first approach, a high order bandpass filter is applied in order to gain sound signals for future automated signal separation.

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Section: Discussionmentioning

confidence: 99%

Detection Technique of Partial Discharges at Impulse Voltage with Appropriate Filter Settings for Signal Separation

2019

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“…In this regard, external sensors are easily installed with higher flexibility; however, the signal received by the antenna could be weak due to the attenuation along the distance between the PD source and sensors. Also, the effect of the surrounding grounded boundary including the grounded drain valve [42], the relative position of the transformer tank around the sensor and its insertion depth, has been demonstrated to influence the results in previous research [16,37]. However, some of these results were based upon software-based simulation and require experimental verification.…”

Section: Uhf Sensors In Partial Discharge Detectionmentioning

confidence: 99%

“…To improve the performance of the antenna, many researchers have examined the optimization of antenna parameters by both simulation and experimental measurements to get a higher level of detection accuracy and sensitivity. Parameters such as S-parameters, voltage stand wave ratio, and input impedance can be measured using a vector network analyzer for comparison between the simulation result and fabricated products [16,37,42]. Other performance-related specifications such as surface current distribution and directivity (gain in E-plane and H-plane) can be observed via simulation using CST Microwave Studio.…”

Section: Uhf Sensors In Partial Discharge Detectionmentioning

confidence: 99%

Application of UHF Sensors in Power System Equipment for Partial Discharge Detection: A Review

Chai

Phung

Mitchell³

2019

Sensors

101

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Condition monitoring of an operating apparatus is essential for lifespan assessment and maintenance planning in a power system. Electrical insulation is a critical aspect to be monitored, since it is susceptible to failure under high electrical stress. To avoid unexpected breakdowns, the level of partial discharge (PD) activity should be continuously monitored because PD occurrence can accelerate the aging process of insulation in high voltage equipment and result in catastrophic failure if the associated defects are not treated at an early stage. For on-site PD detection, the ultra-high frequency (UHF) method was employed in the field and showed its effectiveness as a detection technique. The main advantage of the UHF method is its immunity to external electromagnetic interference with a high signal-to-noise ratio, which is necessary for on-site monitoring. Considering the detection process, sensors play a critical role in capturing signals from PD sources and transmitting them onto the measurement system. In this paper, UHF sensors applied in PD detection were comprehensively reviewed. In particular, for power transformers, the effects of the physical structure on UHF signals and practical applications of UHF sensors including PD localization techniques were discussed. The aim of this review was to present state-of-the-art UHF sensors in PD detection and facilitate future improvements in the UHF method.

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“…At present, the detection methods of PD of a power transformer mainly include electric measurements, ultrasonic method, optical method, and the ultrahigh‐frequency (UHF) method . UHF method has the advantages of strong resistance to onsite electromagnetic (EM) interference and high sensitivity and has been widely applied for the online monitoring of PD of power transformers .…”

Section: Introductionmentioning

confidence: 99%

Ladder‐Wise calculation method for z‐coordinate of transformer PD source based on planar layout UHF antenna sensors

Zhang

Cheng

et al. 2019

IEEJ Transactions Elec Engng

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In locating a transformer partial discharge (PD) source, there is a large fluctuation error in the z -coordinate of the location, which results with planar layout ultrahigh-frequency (UHF) antenna sensors. For the large fluctuation error, this paper first theoretically analyzes the reason. According to the theoretical analysis results, a ladder-wise calculation method of the PD source z -coordinate is proposed: first, the x -and y-coordinates of the PD source are calculated, then the univariate equation f (z ) is derived, and the z -coordinate of the PD source is obtained by f (z ). Finally, the positioning effect of the ladder-wise calculation method for PD source z -coordinate is verified experimentally. Experimental results show that the proposed method can reduce the fluctuation of the z -coordinate of the PD source from 0.6 to 0.2, and when the PD location sample set is ≥10, the average absolute error of the z -coordinate is reduced from about 0.4 m to less than 0.1 m.

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UHF PD measurements on power transformers-advantages and limitations

Cited by 51 publications

References 12 publications

Detection Technique of Partial Discharges at Impulse Voltage with Appropriate Filter Settings for Signal Separation

Detection Technique of Partial Discharges at Impulse Voltage with Appropriate Filter Settings for Signal Separation

Application of UHF Sensors in Power System Equipment for Partial Discharge Detection: A Review

Ladder‐Wise calculation method for z‐coordinate of transformer PD source based on planar layout UHF antenna sensors

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