Effect of DC testing water tree deteriorated cable and a preliminary evaluation of VLF, as alternate

Eager, G. S.; Fryszczyn, B.; Katz, C.; ElBadaly, H.A.; Jean, A.R.

doi:10.1109/tdc.1991.169482

Cited by 13 publications

(6 citation statements)

References 11 publications

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“…Advancements in power electronics enabled robust VLF hardware design and VLF diagnostic testing has been nowadays considered as a promising tool for regular monitoring of insulation systems. Moreover, the advantages of having lightweight and easy transportation have made this system popular among other insulation testing techniques [18,22].…”

Section: Different Voltage Sources and Suitabilitymentioning

confidence: 99%

“…The complex permittivity ɛ(ω) can be resolved as a real part ε′(ω) = ℜe ε(ω) = 1 + χ′(ω) (22) and an imaginary part…”

Section: Frequency-domain Dielectric Responsementioning

confidence: 99%

“…In the mid-1980s, however, DC testing has shown unsuitability for service-aged polymer-insulated cable. One of the prime reasons is that DC hi-pot testing can introduce considerable space charge and may be injurious to the cable insulation [22,23]. The drawbacks of DC testing evidently necessitate seeking alternative sources [18,22].…”

Section: Introductionmentioning

confidence: 99%

“…One of the prime reasons is that DC hi-pot testing can introduce considerable space charge and may be injurious to the cable insulation [22,23]. The drawbacks of DC testing evidently necessitate seeking alternative sources [18,22]. As an old-fashioned testing system, AC power frequency (50/60 Hz) hi-pot could be an alternative.…”

Section: Introductionmentioning

confidence: 99%

“…However, the bulky size, weight, transportation and cost make this testing system mostly inapplicable for field testing [5,23]. An alternative to excitation with power frequency, very low frequency (VLF) and oscillating wave technologies has been introduced to facilitate a practical and convenient solution [22,[24][25][26]. Previously, a simple withstand (go/no-go) test has been widely used, in which the cable insulation either passes or fails the test.…”

Section: Introductionmentioning

confidence: 99%

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Diagnostic challenges in dielectric loss assessment and interpretation: a review

Morsalin

Phung

Danikas

et al. 2019

IET sci. meas. technol.

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Section: Different Voltage Sources and Suitabilitymentioning

confidence: 99%

“…The complex permittivity ɛ(ω) can be resolved as a real part ε′(ω) = ℜe ε(ω) = 1 + χ′(ω) (22) and an imaginary part…”

Section: Frequency-domain Dielectric Responsementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Diagnostic challenges in dielectric loss assessment and interpretation: a review

Morsalin

Phung

Danikas

et al. 2019

IET sci. meas. technol.

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New after‐laying test methods for XLPE cable lines

Uchida¹,

Kobayashi²,

Kawashima³

et al. 1996

Electrical Engineering Japan

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An after-laying test is required to demonstrate the soundness of XLPE underground cable lines with joints. AC voltage application is desirable for the test; however, the equipment for ac application must be very large because it must supply large capacitive current for cables. DC voltage is normally applied, which can be supplied with small equipment; however, the effectiveness of the dc application is questioned because the electrical stress distribution is quite different from that with ac application and, moreover, dc application could damage insulation properties of cables.The authors targeted the Oscillating Wave (OSW) method and the Very Low-Frequency (VLF) method as alternative after-laying tests. They first developed modeling methods of various defects on underground cable lines and applied OSW and VLF to these defect models. They found that OSW and VLF methods have higher fault detection capability than dc voltage application. They also demonstrated that the defects which can be easily detected with the OSW method are 18ISSN0424-7760/9610006-00 18 0 1996 Scripta Technica, Inc.

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Application of high resolution radar to provide non-destructive test techniques for locating URD cable faults and splices

Banker

Nannery

Tarpey

et al. 1994

IEEE Trans. Power Delivery

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A non-destructive, high resolution radar (HRR) system that precisely locates faults and splices has been developed. High resistance faults are identified without thumping via a low energy, battery-powered snapshot unit. Only enough dc voltage to initiate and maintain one flashover at the fault is applied; the duration is limited to four milliseconds.Pinpointing the fault or splice is accomplished by detecting the radar signal above ground. SJhen the antenna is directly over the fault or splice, the location is confirmed. The ability to receive the signal from the cable makes the pinpointing step independent of cable propagation velocity.during testing, users have lowered thumping and hipot test voltages where possible, and then used radar techniques to assist in locating faults. However, accurate fault and splice locating is still a challenge for utility personnel. Intensive training a n d c o n t i n u e d u s e by an operator is r e q u i r e d t o o b t a i n a n d m a i n t a i n o p e r a t i n g proficiency.Although advances have been made in URD cable fault locating methods and equipment, it was determined that applying new technology could provide significant improvement.The following goals were established for this new approach: 1.Identify and pinpoint faults without causing additional damage to cable. 2.Identify and pinpoint splices. INTRODUCTION .Simplify locating equipment and methods. As the early vintage polyethylene cable URD systems of the 60's and 7 0 ' s approach the end of their service life, the number of cable failures continues to be an increasing reliability problem for electric utilities. Unlike an overhead distribution system, where the failure can be visually located and easily repaired, URD cable failures all too often result in difficulty in locating and isolating the faulty cable section and in pinpointing the exact fault location. I n addition t o b e i n g t o o inaccurate and difficult to operate, conventional fault locating and proof testing methods have been shown to be detrimental to polyethylene insulation with water trees [1,2,31. While locating a fault with high voltage J X (hi-pot or thumper), additional damage is done throughout the cable, reducing its already limited life expectancy. In order to minimize damage 93 SN 364-0 PWRD by the IEEE Insulated Conductors Committee of the IEEE Power Engineering Society for presentation at the IEEE/Reduce test equipment size and improve portability. IMPROVED FAULT LOCATION TECHNOLOGYTo address the goals, a new location technique has been developed. Its operation is based on significant improvements achieved by using enhanced, high resolution radar (HRR). High speed data capture and processing in conjunction with HRR allow the use of a low energy high voltage snapshot unit and new field locating methods. Present radar systems based on Time Domain Reflectometry (TDR) transmit a single pulse down the cable and indicate reflections as an analog trace on an oscilloscope. Range precision is limited by the small choice of scales provided on ...

show abstract

Effect of DC testing water tree deteriorated cable and a preliminary evaluation of VLF, as alternate

Cited by 13 publications

References 11 publications

Diagnostic challenges in dielectric loss assessment and interpretation: a review

Diagnostic challenges in dielectric loss assessment and interpretation: a review

New after‐laying test methods for XLPE cable lines

Application of high resolution radar to provide non-destructive test techniques for locating URD cable faults and splices

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