Computation of the Electric Field in Cable Insulation in the Presence of Water Trees and Space Charge

Stancu, Cristina; Notingher, P.; Ciuprina, Florin; Castellon, J.; Agnel, S.; Toureille, A.

doi:10.1109/tia.2008.2009659

Cited by 31 publications

(9 citation statements)

References 29 publications

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“…5 for the four water tree lengths considered. It can be observed that the water tree presence determines an increase of the field outside the tree and a decrease of the field inside the tree, which was already reported in previous studies [8][9][10]. The longer the tree, the higher is the field in the untreed region of the insulation.…”

Section: Resultssupporting

confidence: 73%

“…Most of the models referred to the vented water trees, some of them considering continuous treed regions [7,9], while other approaches proposing individual tree models [8,9]. The time invariant electric field was studied in most of the models, many of them being developed in electrostatic regime [8][9][10][11], and some in steady state electric conduction regime [12]. First electrostatic models have considered only permittivity values of the polymer and water trees, but zero volume charge density, while further development have taken into account the space charge presence into water treed insulation.…”

Section: Introductionmentioning

confidence: 99%

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Electric field distribution in power cable insulation affected by water trees

Andrei

Vlad

Ciuprina

2015

2015 9th International Symposium on Advanced Topics in Electrical Engineering (ATEE)

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Electrostatic numerical models of cable insulation affected by cavities, vented and bow-tie water trees are proposed in this study. The influence of the vented tree lengths on the electric field in the untreed polymer, in a cavity in front of the tree, and in a bow-tie tree growing toward the vented tree is analyzed. The values and spatial distribution of relative permittivity and space charge in the subdomains of the 3D computational domain are set by scaling experimental results from literature. The models are implemented in the finite element method based on the software package COMSOL Multiphysics.

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Section: Resultssupporting

confidence: 73%

Section: Introductionmentioning

confidence: 99%

Electric field distribution in power cable insulation affected by water trees

Andrei

Vlad

Ciuprina

2015

2015 9th International Symposium on Advanced Topics in Electrical Engineering (ATEE)

Self Cite

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“…The main effect of this phenomenon is the distortion of the original Laplacian electric field distribution, which could cause extremely high local electric fields. This in turn may cause the insulating material to degrade and this fact can lead in turn to electrical breakdown [30,31]. To better explain this phenomenon, in Figure 1 a HVDC cable with accumulated space charges is illustrated.…”

Section: The Space Charge Accumulation Phenomenonmentioning

confidence: 99%

The Industrial Applicability of PEA Space Charge Measurements, for Performance Optimization of HVDC Power Cables

et al. 2019

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Cable manufacturing industries are constantly trying to improve the electrical performance of power cables. During the years, it was found that one of the most relevant degradation factors influencing the cable lifetime is the presence of space charge in the insulation layer. To detect the accumulated charge, the pulsed electro-acoustic (PEA) method is the most used technique. Despite the wide use of the PEA cell, several issues are still present. In particular, the PEA output signal is strongly disturbed by the acoustic waves reflections within the PEA cell. This causes the distortion of the output signal and therefore the misinterpretation of the charge profiles. This, in turn, may result in an incorrect cable characterization from the space charge phenomenon point of view. In 2017, due to the proved degradation effect of the space charge accumulation phenomenon, the IEEE Std 1732 was developed. This standard describes the steps to be followed for the space charge measurement in cables specimens during pre-qualification or type tests. Therefore, cable manufacturing industries started to take a particular interest in these measures. In the light of this, the aim of the present work is to highlight that the enacted standard is not easily applicable since various problems are still present in the PEA method for cables. In particular, in this work, the effect of multiple reflected signals due to the different interfaces involved, but also the effect of the signal attenuation due to cable dielectric thickness, as well as the effect of the PEA cell ground electrode thickness in the output charge profile, are reported. These issues have been demonstrated by means of an experimental test carried out on a full-size cable in the Prysmian Group High Voltage laboratory. To better understand the PEA cell output signal formation, a PEA cell model was developed in a previous work and it has been experimentally validated here. In particular, simulations have been useful to highlight the effect of the reflection phenomena due to the PEA cell ground electrode thickness on the basis of the specimen under test features. Moreover, by analyzing the simulation results, it was possible to separate the main signal from the reflected waves and, in turn, to calculate the suitable ground electrode thickness for the cable specimen under test.

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“…The growth of water trees causes an increase of the electric conductivity, permittivity and dielectric losses in insulations [6,7]. In the process of monitoring, the existence of water tree will cause variety of the capacitance between the driving and the sensing electrodes.…”

Section: Water Tree Detection Modulementioning

confidence: 99%

A Novel FEF Method for Insulation Status Monitoring of Underground Power Cables

Dian¹,

Liang²,

Lou³

et al. 2013

JCP

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Monitoring on underground power cables in a close-fitting manner using mobile robot can acquire more actual information about insulation status of cables. Focusing on a water tree detection module in the monitoring system, this paper proposes fringing electric field (FEF) method to detect probably formed water tree in the insulation layer. An arch substrate based interdigital FEF sensor is designed to reduce the disturbance caused by applying traditional interdigital FEF sensor in the water tree detection. The mathematical model of the novel sensor is built by finite element method. Comparison of the electric field distribution that produced by the above two kinds of sensors is carried out by finite element analysis. Effect on novel sensor performance caused by excitation frequency is discussed. Parameters of the proposed sensor are optimized by analyzing the electric field penetrability with varying finger width and electrode separation. Simulation results demonstrate the sensor's design is reasonable and the electric field penetrability of the novel sensor is remarkably improved compared with traditional interdigital FEF sensor.

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Computation of the Electric Field in Cable Insulation in the Presence of Water Trees and Space Charge

Cited by 31 publications

References 29 publications

Electric field distribution in power cable insulation affected by water trees

Electric field distribution in power cable insulation affected by water trees

The Industrial Applicability of PEA Space Charge Measurements, for Performance Optimization of HVDC Power Cables

A Novel FEF Method for Insulation Status Monitoring of Underground Power Cables

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