Bandwidth and sensitivity issues in PD detection in power cables

Chandrasekar, S.; Cavallini, A.; Montanari, Gian Carlo; Puletti, F.

doi:10.1109/tdei.2007.369538

Cited by 23 publications

(7 citation statements)

References 11 publications

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“…The bandwidth is 100 kHz to 20 MHz and the rise time is 20 ns. In case of higher voltage cables, this bandwidth is considered to give the most sensitive measurement [15][16][17][18][19]. The second HFCT is a very high bandwidth Tektronix CT -1 [20] device (later referred to as GHz HFCT or HFCT-G), originally designed for measuring high frequency electronics, however, the measurement was arranged in a way that it enabled the application of this device.…”

Section: Methodsmentioning

confidence: 99%

Repetition Rate of Partial Discharges in Low Voltage Cables

Cselko

2019

Period. Polytech. Elec. Eng. Comp. Sci.

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Diagnostic testing of low voltage cables by partial discharge measurement has several difficulties. One of them is that the cables are not designed to be partial discharge free at their test voltage. As partial discharge impulses may originate from numerous spots even in new cables, it is expected that impulses reach the termination with high repetition rate. The propagation of impulses in low voltage cables differs from the medium and high voltage cables; there is no lossy semiconducting layer or layers, but the cross section of the conductors are lower. The measurement method of partial discharges has to be adjusted to the discharge type and the propagation path as these determine the frequency content of the individual impulses, and the time resolution of the system has to be appropriate for the expected repetition rate. Measurements have been performed on various types of cables by different methods. Based on the results suggestions are given on the suitable measurement methods.

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Section: Methodsmentioning

confidence: 99%

Repetition Rate of Partial Discharges in Low Voltage Cables

Cselko

2019

Period. Polytech. Elec. Eng. Comp. Sci.

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“…The signal-to-noise ratio is about 10. The absolute noise level is between 20 and 40 mV, which is a typical noise level for online PD measurements according to [14]. It can be seen that the algorithm detects all five peaks of the input signal, i. e., all PD occurrences.…”

Section: Hf Measurement and Pd Detectionmentioning

confidence: 99%

High-Frequency Current Transformer With Variable Air Gap for Power Cable Monitoring

Fritsch,

Wolter

2024

IEEE Trans. Instrum. Meas.

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This article deals with partial discharge (PD) measurement on power cables while they are in operation (online monitoring). In terms of sensitivity, high-frequency current transformers (HFCTs) are the most suitable sensors for this task, but they are prone to magnetic saturation when monitoring power cables online. To counteract saturation, the magnetic ring core of the HFCT is usually split into two halves to create air gaps. We show that a variable air gap length is required to maximize the HFCT sensitivity, and that the optimal air gap length depends on the actual operating point of the power cable. Accordingly, we present a concept for the construction of an HFCT capable of self-adjusting its air gap length during operation. The air gap control strategy is explained in detail and tested with a prototype. In addition, we propose a method for PD detection based on a combination of an analog peak detector circuit followed by a software algorithm. The developed PD sensor is immune to magnetic saturation, always operates at its optimum operating point and can therefore detect PD pulses with much higher sensitivity than comparable sensors with a fixed air gap length. Our tests prove that the sensor system works as intended and will be further improved in the future.

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“…Thanks to equations (5)- (8) and to TDR measurements, it has been possible to characterize the cable under test and confirm the predominant behaviour of skin effect with respect to the dielectric losses below 1 MHz.…”

Section: Attenuation Constantmentioning

confidence: 99%

“…A few analytical models have been developed and investigated to achieve mathematical tool suitable to characterize power cables up to hundreds of MHz and, therefore, simulate PD pulse propagation [4,[8][9][10][11][12][13][14][15]. These models can be very useful to highlight the influence on propagation constant characteristics of cable materials properties.…”

Section: Analytical Cable Modelsmentioning

confidence: 99%

See 1 more Smart Citation

PD detection in extruded power cables: an approximate propagation model

Tozzi

Cavallini

Montanari

et al. 2008

IEEE Trans. Dielect. Electr. Insul.

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In order to improve partial discharge (PD) detection and location in extruded power cables, Ultra-Wide Bandwidth detectors (UWB) can be preferred to wide-and narrowband systems. As UWB systems aim to get the broadest frequency content in PD pulses, it is important to evaluate the frequency attenuation as a function of distance propagated of the cable under test, trying to achieve optimum signal-to-noise ratio (SNR) and large detection sensitivity. Some conventional techniques able to calculate attenuation and dispersion of PD pulses are considered and a fast approximate model is developed in this paper, trying to provide a simple tool to estimate the maximum PD detection length in polymeric cable, in relation to bandwidth measurement system and required sensitivity.

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Bandwidth and sensitivity issues in PD detection in power cables

Cited by 23 publications

References 11 publications

Repetition Rate of Partial Discharges in Low Voltage Cables

Repetition Rate of Partial Discharges in Low Voltage Cables

High-Frequency Current Transformer With Variable Air Gap for Power Cable Monitoring

PD detection in extruded power cables: an approximate propagation model

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