Development of Harmonic-Noise Reduction Technology in Diagnostic Method using AC Loss Current for Water Treed XLPE Cable

Tsujimoto, Tomiyuki; Nakade, Masahiko; Yagi, Yukihiro; Ishii, Noboru

doi:10.1541/ieejpes.125.1237

Cited by 7 publications

(4 citation statements)

References 4 publications

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“…Incidentally, a

0true 3 ω_{c}

current component is generated when

0true V_{s} (t)

in Eq. is replaced by the mains voltage

V (t) = V_{0} sin (ω_{c} t + φ_{c}) .

However, in the above‐mentioned loss current method, it appears that this current is detected as part of the degradation signal (because the current is also produced at n = 2 and higher) .…”

Section: Resultsmentioning

confidence: 99%

“…However, in the above-mentioned loss current method, it appears that this current is detected as part of the degradation signal (because the current is also produced at n = 2 and higher) [2,8].…”

Section: Characteristics Of Ac Superposition Currentmentioning

confidence: 99%

“…Consequently, degradation diagnosis of extra-high voltage XLPE cables is an urgent issue [1]. Typical degradation diagnosis techniques approved for real lines include the dielectric tangent method [1], using the commercial frequency or a low frequency, the loss current method [2], based on the amplitude and phase of mainly the third harmonic present of the ac loss current, and the residual charge method [3], based on measurement of the electric charge accumulated in the water-tree region due to dc prestress and then released under ac stress. However, these diagnosis techniques require further improvement in some respects, such as detection accuracy, protection of service cables, and the effects of dc prestress on gas-insulated devices.…”

Section: Introductionmentioning

confidence: 99%

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Application of the AC Superposition Method to Degradation Diagnosis of 22/33‐kV Class XLPE Cables

Kumazawa

2015

Electrical Engineering Japan

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SUMMARY Water trees in the insulator of XLPE cable may considerably reduce the dielectric breakdown voltage, thus being an important lifetime‐governing factor. The ac superposition method we have investigated is a new technique for hot‐line diagnosis of 6.6‐kV XLPE cables, and the diagnostic apparatus using this technique is now widely used in the distribution line field. In order to study the application of the ac superposition method to degradation diagnosis of 22/33‐kV class XLPE cables, we measured deterioration signals of the cables with water trees by a modification of the above diagnostic apparatus. The deterioration signals, hereafter called “ac superposition current”, were generated by an amplitude modulation effect due to the nonlinear resistance of water trees. Moreover, we evaluated the relationship between the ac superposition current and the ac breakdown voltage. It is difficult to judge whether a correlation between then is present or not because of the uneven distribution of the measured data. However, the ac superposition current tends to increase linearly with a decrease in the residual thickness of the insulator. For example, the ac superposition current was about 40 nA when the residual thickness decreased to 3 mm. Thus, we consider that the ac superposition method is effective for degradation diagnosis of 22/33‐kV class XLPE cables.

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“…Incidentally, a

0true 3 ω_{c}

current component is generated when

0true V_{s} (t)

in Eq. is replaced by the mains voltage

V (t) = V_{0} sin (ω_{c} t + φ_{c}) .

However, in the above‐mentioned loss current method, it appears that this current is detected as part of the degradation signal (because the current is also produced at n = 2 and higher) .…”

Section: Resultsmentioning

confidence: 99%

Section: Characteristics Of Ac Superposition Currentmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Application of the AC Superposition Method to Degradation Diagnosis of 22/33‐kV Class XLPE Cables

Kumazawa

2015

Electrical Engineering Japan

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“…According to the report that summarized a survey conducted by a working group in the Nuclear Energy Agency, the Organisation for Economic Co-operation and Development (NEA, OECD) [8], several cables, especially those used in nuclear power plants in the US, had been damaged by water trees. Although trials to develop on-site real-time cable condition monitoring methods [9][10][11][12][13][14][15][16][17][18][19] have been made actively in several institutes, there exist no truly reliable nondestructive methods to detect various damages induced in cables. In the present study, we have examined the applicability of the broadband impedance spectroscopy (BIS) to locate the degradation of cable insulation.…”

Section: Introductionmentioning

confidence: 99%

Diagnosis of cable aging by broadband impedance spectroscopy

Ohki

Yamada

Hirai

2011

2011 Annual Report Conference on Electrical Insulation and Dielectric Phenomena

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Since electric wires and cables play very important roles of supplying electric power and transmitting information and control signals, their degradation may cause a serious problem. In the present research, we examined the applicability of the broadband impedance spectroscopy (BIS) to monitor the degradation of cable insulation. The BIS method is to measure the magnitude and phase angle of impedance as a function of frequency in a very wide frequency range. First, cables were aged partially by heat and γ-rays. Further, a hole was drilled from the outer to inner conductors in some cables, and was filled with a NaCl solution in order to simulate a vented water tree. The difference in magnitude or phase angle of impedance before and after the aging becomes clearer by fast Fourier transform analyses, regardless of whether the aging was given by the γ-rays or water trees. The location of the degradation was also possible without referring to the data before the aging. These results clearly indicate that the BIS method has a potential ability to locate the degradation of cable insulation induced by various kinds of damages.

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Location feasibility of degradation in cable through Fourier transform analysis of broadband impedance spectra

Ohki

Hirai

2013

Electrical Engineering Japan

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Since electric cables play important roles such as power supply and information transmission, their degradation may cause serious problems. We have been trying to monitor the degradation of cable insulation by measuring the magnitude and phase angle of the impedance as a function of frequency in a very wide frequency range. The cables tested were insulated with ﬂame‐retardant ethylene propylene rubber or special heat‐resistant polyvinyl chloride. They were partially damaged by peeling off their insulation layers, or partially aged by heat and γ‐rays. The impedance and phase angle were measured from a terminal of the cable. The difference in impedance between the damaged and sound cables is made clear by fast Fourier transform analyses, from which the damaged portion can be located. It can be clearly shown that this method has the potential ability to detect the degradation of cable insulation induced by physical damage, γ‐ray irradiation, and thermal aging. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 183(1): 1–8, 2013; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.22384

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Development of Harmonic-Noise Reduction Technology in Diagnostic Method using AC Loss Current for Water Treed XLPE Cable

Cited by 7 publications

References 4 publications

Application of the AC Superposition Method to Degradation Diagnosis of 22/33‐kV Class XLPE Cables

Application of the AC Superposition Method to Degradation Diagnosis of 22/33‐kV Class XLPE Cables

Diagnosis of cable aging by broadband impedance spectroscopy

Location feasibility of degradation in cable through Fourier transform analysis of broadband impedance spectra

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