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1
Bilan, T., I. Rezvik, O. Sakhno, O. But, and S. Bogdanov. "Main Approaches to Cable Aging Management at Nuclear Power Plants in Ukraine." Nuclear and Radiation Safety, no. 4(84) (December 19, 2019): 54–62. http://dx.doi.org/10.32918/nrs.2019.4(84).07.
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The mechanisms of cable ageing at nuclear power plants (NPPs) mainly depending on the insulation material, as well as the damaging factors affecting cables that are determined by the operating conditions are considered in the paper. The main and additional mechanisms of aging resulting from the effects of damaging factors are provided. The paper presents the main methods of cable aging management: determining the actual service life and testing using field methods and other means. The basic principles for the arrangement of cable aging management at Ukrainian NPPs, as well as the methods used to investigate the technical condition of cables, are presented. A list of mandatory lists has been defined when performing activities on cable aging management. A methodology is described for lifetime extension of cables, and conditions for extending the service life of cables that are in service are provided. A number of methods of testing cables for aging management are considered: visual inspection of insulation and measurement of crack size, discoloration, etc.; insulation hardness test; insulation chemical analysis; electrical insulation tests; tensile strength measurement; measurement of elongation at break; measurements of dielectric loss at low frequency or sweep frequency; testing by dynamic reflectometry method; AC and DC current impedance measurements. The paper presents results of separate laboratory studies for selected 1 kV representative power cables with PVC insulation of SUNPP-1, ZNPP-1 and KhNPP-2 conducted within Ukrainian NPP long-term operation, which included a stage of laboratory examination and examination of cable samples in operating conditions. The following results were obtained: dependence of VVGng 4x6 cable lifetime on operating temperature; dependence of AVVG cable lifetime on operating temperature; dependence of AVVG (a) cable lifetime on operating temperature. There are possibilities and conditions under which the use of cables within long-term operation is permissible.
2
Lee, Seok-Hui, Min-Ho Kim, Sangkyu Lee, Ju-Eun Lee, and Min-Chul Lee. "Analysis of Combustion and Smoke Characteristics According to the Aging of Class 1E Cables in Nuclear Power Plants." Fire Science and Engineering 35, no. 1 (February 28, 2021): 20–27. http://dx.doi.org/10.7731/kifse.970c894b.
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In this study, combustion and smoke characteristics according to the aging of class 1E cables in nuclear power plants were analyzed through a cone calorimeter test. In the case of combustion characteristics, during the early period, which was the first peak of the heat release rate, the peak value of the non-aged cable was higher by approximately 20-50 kW/m<sup>2</sup> than that of aged cables. However, in the mid-late periods, which was the second peak, the value of the aged cables were higher than the non-aged cable due to the decrease in flame retardant performance with aging deterioration. In addition, the duration of the char layer of the aged cables was shortened by 200 s than that of the non-aged cables due to the unstable formation of char layer. The total heat release measured was approximately 1.4 times higher in the aged cables than in the non-aged cables. In the case of smoke characteristics, the smoke production rate and total smoke release show a similar trend with the heat release rate and total heat release. The total smoke release of the aged cables was measured to be higher than that of the non-aged cables. The tendency of the smoke factor increased with aging deterioration, and the values of the smoke factor in the aged cables beyond 4 years were approximately 1.76-2.0 times different from those in the non-aged cables. Consequently, the smoke risk increased with aging deterioration. Therefore, the risk of heat and smoke release increased as aging progressed.
3
He, Dongxin, Tao Zhang, Meng Ma, Wenjie Gong, Wei Wang, and Qingquan Li. "Research on Mechanical, Physicochemical and Electrical Properties of XLPE-Insulated Cables under Electrical-Thermal Aging." Journal of Nanomaterials 2020 (February 3, 2020): 1–13. http://dx.doi.org/10.1155/2020/3968737.
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The stabilization of cross-linked polyethylene (XLPE) cables is crucial to the safe working of power systems. In order to investigate the aging characteristics of cable insulation in the process of operation, 10 kV XLPE cables were electrically-thermally aged at an AC voltage of 26.1 kV and three temperatures: 103°C, 114°C, and 135°C. Cable samples at five aging stages were cut into slices and tested to determine their mechanical, physicochemical properties and dielectric strength. The changes in these properties were analyzed in terms of aging time. The mechanical strength and oxidation induction time have the same changing trend of decrease, because the chemical bonds of the cable insulation material are fractured when the XLPE cable is aged. The AC space charge presented a trend of gradual accumulation with aging time. The breakdown field strength after AC voltage application decreases monotonically with aging time, which could be a characteristic index to evaluate the degradation degree of the cable insulation. This research contributes to the comprehension of degradation mechanism and discovery of aging assessment criteria, which is of great significance in assessments of insulation properties and fault detection on power cables.
4
Matery, Tatiyana, and Vladimir Kim. "Enhancing Resistance of Cables to Hydrocarbons." Applied Mechanics and Materials 792 (September 2015): 572–77. http://dx.doi.org/10.4028/www.scientific.net/amm.792.572.
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An aging in hydrocarbon fluids (the transformer oil and diesel fuel) of cables with sheaths produced of polymers having different resistance to swelling and using different extruders has been carried out. While the aging resistance of cables is mainly determined by the resistance of its polymer sheath to the swelling, it is shown that the cable resistance to aging in hydrocarbons can be significantly increased by using of twin extruder to produce a two-layer sheath in one operation. This way of sheathing is proposed to increase the oil resistance of cables.
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Yahya, Muhammad Bin, and Muhammad Nazrolni Azmi Bin Izani. "Cable Test and Breakdown Voltage Determination of Joysense Cable Insulation." Indonesian Journal of Electrical Engineering and Computer Science 8, no. 1 (October 1, 2017): 177. http://dx.doi.org/10.11591/ijeecs.v8.i1.pp177-183.
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Cross-linked Polyethylene (XLPE) has been used as the insulation for polymeric power cables for its superior advantages. This type of cable insulation are famously known and used for their good dielectric properties, mechanical properties, thermal properties, and probability to be utilized at high temperature. This study is of four (4) parts; designing suitable method for cable test, accelerated testing procedures applied to XLPE insulation for high voltage cables, online partial discharge determination, and aging test. To study the insulation durability to AC high voltage operation, the breakdown strength and aging were investigated under different setting of temperature. The breakdown voltages of XLPE were measured at different temperatures of 30<sup>0</sup>C, 50<sup>0</sup>C and finally at 70<sup>0</sup>C. Lastly, the aging effect of cable insulation was observed by conducting the AC breakdown voltage test after the aging process. Results showed that the breakdown voltage and aging of XLPE cables will decrease with increase of temperature setting.<em> </em>
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Kim, Min Ho, Hyun Jeong Seo, Sang Kyu Lee, and Min Chul Lee. "Influence of Thermal Aging on the Combustion Characteristics of Cables in Nuclear Power Plants." Energies 14, no. 7 (April 5, 2021): 2003. http://dx.doi.org/10.3390/en14072003.
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In this study, the combustion characteristics and emission of toxic gases of a non-class 1E cable in a nuclear power plant were investigated with respect to the aging period. A thermal accelerated aging method was applied using the Arrhenius equation with the activation energy of the cables and the aging periods of the cables set to zero, 10, 20, 30 and 40 years old by considering the lifetime of a nuclear power plant. According to ISO 5660-1 and ISO 19702, the cone calorimeter Fourier transform infrared spectroscopy test was performed to analyze the combustion characteristics and emission toxicity. In addition, scanning electron microscopy and an energy dispersive X-ray spectrometer were used to examine the change in the surface of the sheath and insulation of the cables according to the aging periods. To compare quantitative fire risks at an early period, the fire performance index (FPI) and fire growth index (FGI) are derived from the test results of the ignition time, peak heat release rate (PHRR) and time to PHRR (tPHRR). When comparing FPI and FGI, the fire risks decreased as the aging period increased, which means that early fire risks may be alleviated through the devolatilization of both the sheath and insulation of the cables. However, when comparing heat release and mass loss, which represent the fire risk at the mid and late period, fire intensity and severity increased with the aging period. The emission of toxic gases coincided with the results obtained from the heat release rate, which confirms that the toxicity of non-aged cables is higher than that of aged cables. From the results, it can be concluded that the aging period significantly affects both the combustion characteristics and toxicity of the emission gas. Therefore, cable degradation with aging should be considered when setting up reinforced safety codes and standards for cables and planning proper operation procedures for nuclear power plants.
7
Mustafa, Ehtasham, Ramy S. A. Afia, and Zoltán Ádám Tamus. "Condition Monitoring Uncertainties and Thermal - Radiation Multistress Accelerated Aging Tests for Nuclear Power Plant Cables: A Review." Periodica Polytechnica Electrical Engineering and Computer Science 64, no. 1 (September 23, 2019): 20–32. http://dx.doi.org/10.3311/ppee.14038.
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The low voltage cables in the nuclear power plant have the same importance as veins have in the human body. Since, the cables inside the containment are under a number of environmental stress, out which the thermal and radiation stresses are important and become more effective with the presence of oxygen. These stresses cause the degradation of the insulation and hence may lead to insulation failure. To study the behavior of the cables under the nuclear power plant environmental stress, the cables are subjected to accelerated aging tests in laboratories which helps in determining their withstand capacity and degradation behavior in the harsh thermal-radiation environment. In this paper, the accelerated aging tests conditions are discussed with the focus on the role of certain uncertainty factors which effect the aging markers during the condition monitoring of the insulation material of cable after the accelerated aging tests. This review has been put into a framework to better understand the aging process in the low voltage nuclear power plant cables. In the conclusion part, some future directions in the field of the thermal-radiation multi-stress accelerated aging tests and condition monitoring techniques are also identified.
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Zapf, Martin, Tobias Blenk, Ann-Catrin Müller, Hermann Pengg, Ivana Mladenovic, and Christian Weindl. "Lifetime Assessment of PILC Cables with Regard to Thermal Aging Based on a Medium Voltage Distribution Network Benchmark and Representative Load Scenarios in the Course of the Expansion of Distributed Energy Resources." Energies 14, no. 2 (January 18, 2021): 494. http://dx.doi.org/10.3390/en14020494.
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The decentralized feed-ins from distributed energy resources (DER) represent a significant change in the manner in which the power grid is used. If this leads to high loads on electrical equipment, its aging can be accelerated. This applies in particular with regard to the thermal aging of older generations of power cables, namely paper insulated lead covered (PILC) cables. This type of power cable can still be found frequently in medium voltage (MV) networks. If aging of these cables is significantly accelerated in the presence of DER, distribution system operators (DSO) could face unplanned premature cable failures and a high replacement demand and costs. Therefore, this paper investigates the thermal aging of PILC cables in a MV distribution network benchmark for different load scenarios, using standardized load profiles and representative expansion scenarios for wind power and photovoltaics plants in particularly affected network areas in Germany. A main objective of this paper is to present a methodology for estimating the thermal degradation of PILC cables. An approach is used to draw simplified conclusions from the loading of cables to their conductor or insulation temperature. For this purpose, mainly Joule losses are considered. In addition, thermal time constants are used for the heating and cooling processes. Based on the insulation temperature, thermal aging is determined using the Arrhenius law or the Montsinger rule. However, it is important to note that there is an urgent need for research on reference data in this area. For this reason, the results of the lifetime estimation presented in this paper should only be considered as an approximation if the selected reference data from the literature for the aging model are actually applicable. The lifetime assessment is performed for a highly utilized line segment of the network benchmark. Accordingly, extreme values are examined. Different operational control strategies of DSO to limit cable utilization are investigated. The results show that the expansion of DER can lead to a short but high cable utilization, although the average utilization does not increase or increases only slightly. This can lead to significantly lower cable lifetimes. The possible influence of these temporarily high loads is shown by comparing the resulting cable lifetime with previous situations without DER. It is also shown that DSO could already reduce excessive aging of PILC cables by preventing overloads in a few hours of a year. In addition to these specific results, general findings on the network load due to the influence of DER are obtained, which are of interest for congestion management.
9
Afia, Ramy S. A., Ehtasham Mustafa, and Zoltán Ádám Tamus. "Comparison of Mechanical and Low-Frequency Dielectric Properties of Thermally and Thermo-Mechanically Aged Low Voltage CSPE/XLPE Nuclear Power Plant Cables." Electronics 10, no. 22 (November 9, 2021): 2728. http://dx.doi.org/10.3390/electronics10222728.
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During the service period of low-voltage nuclear cables, multiple stresses influence the aging of polymeric materials of cables. Thermal and radiation stresses are considered service aging factors in qualification tests, while the standards usually do not prescribe mechanical stress. CSPE/XLPE insulated nuclear cable samples were exposed to thermal and combined thermo-mechanical aging for more than 1200 h at 120 °C. The real and imaginary parts of permittivity were measured in the 200 μHz to 50 mHz range as dielectric properties. The Shore D hardness of the samples was measured to analyze the mechanical characteristics of the cable. To characterize the dielectric spectrum, derived quantities, namely central real and imaginary permittivities and real and imaginary permittivities’ central frequencies were calculated. The change of dielectric spectra did not show a clear trend with aging, but the imaginary permittivity’s central frequency was higher by 0.5 mHz in the case of thermo-mechanically aged samples. The Shore D hardness was also higher on the thermo-mechanically aged samples. These findings show the combined aging has a higher impact on the insulation properties. Hence, involving the mechanical stress in the aging procedure of cable qualification enables the design of more robust cables in a harsh environment.
10
Al-Onazi, Yousef, Nissar Wani, Abdulrahman Al-Arainy, and Yasin Khan. "Insulation Performance Analysis of Field Aged and New MV XLPE Cables Using Various Diagnostic Techniques." E3S Web of Conferences 294 (2021): 02008. http://dx.doi.org/10.1051/e3sconf/202129402008.
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Cross-linked polyethylene (XLPE) cables are widely used in the distribution and transmission networks of power systems. The insulation materials of these cables are stressed by the over voltages and are also exposed to various environmental conditions. This leads the power cables to degrade during their normal life span. Therefore, it would be advantageous for the power utilities to acquire the cable’s insulation condition frequently during their operation. In this paper, experimental studies were carried out on short sections of field aged as well as un-aged medium voltage (MV) XLPE cables to investigate the insulation condition using non-destructive diagnostic techniques such as Dissipation Factor (DF), Isothermal Relaxation Current (IRC), and Partial Discharge (PD) characteristics at 60Hz. From this set of experiments, different parameters will be used to analyze the dielectric response and the insulation condition. Finally, the results show how the VLF dissipation factor works efficiently to assess cable aging.
11
Oleksyuk, I. V. "Aging of Cross-Linked Polyethylene Insulation Cable Lines." ENERGETIKA. Proceedings of CIS higher education institutions and power engineering associations 64, no. 2 (April 9, 2021): 121–29. http://dx.doi.org/10.21122/1029-7448-2021-64-2-121-129.
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Abstract. Preference is given to cable lines with cross-linked polyethylene insulation in electrical networks with a nominal voltage of 10 kV during reconstruction of existing and construction of new industrial enterprises. The standard service life of such cables is at least 30 years (subject to the conditions of storage, transportation, installation and operation), and the actual one is determined by the technical condition of the cable. The service life of a cable line depends on the state of its insulation, the aging of which occurs under the influence of several factors. Conventionally, all factors influencing one or another degree on the cable insulation resource can be divided into thermal, electromagnetic, climatic, mechanical and operational. The most significant reason for the insulation aging is high temperature, which accelerates the reaction of thermo-oxidative destruction, during which high-molecular polymer compounds decompose. In fact, cables are operated at temperatures below the long-term permissible values, and, therefore, the aging of the insulation is slower, and the actual service life will be longer than the standard. At present, condition of the insulation is monitored with the use of high voltage tests related to destructive testing methods. When designing and operating cable lines, it is necessary to estimate the duration of the actual service life under various operating conditions. In theory, there are several expressions for calculating the service life of a cable line when exposed to temperature, humidity, electric field and aggressive environments, but all of them are not applicable in practice due to the presence of a large number of coefficients whose values are unknown. The paper presents an analytical expression obtained for determining the service life of power electric cables, taking into account the aging of the insulation under the influence of temperature and electric field.
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Chen, Hui, Junjia Wang, Hejun Hu, Xiaofeng Li, and Yiyun Huang. "Aging Detection of 110 kV XLPE Cable for a CFETR Power Supply System Based on Deep Neural Network." Energies 15, no. 9 (April 25, 2022): 3127. http://dx.doi.org/10.3390/en15093127.
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To detect the aging of power cables in the TOKAMAK power supply systems, this paper proposed a deep neural network diagnosis model and algorithm for power cable aging, based on logistic regression according to the characteristics of different high-order harmonics generated by different aging parts of the power cable. The experimental results showed that the model has high diagnostic accuracy, and the average error is only 2.35%. The method proposed in this paper has certain application potential in the CFETR power cable auxiliary monitoring system.
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Chen, Hui, Junjia Wang, Hejun Hu, Xiaofeng Li, and Yiyun Huang. "Aging Detection of 110 kV XLPE Cable for a CFETR Power Supply System Based on Deep Neural Network." Energies 15, no. 9 (April 25, 2022): 3127. http://dx.doi.org/10.3390/en15093127.
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To detect the aging of power cables in the TOKAMAK power supply systems, this paper proposed a deep neural network diagnosis model and algorithm for power cable aging, based on logistic regression according to the characteristics of different high-order harmonics generated by different aging parts of the power cable. The experimental results showed that the model has high diagnostic accuracy, and the average error is only 2.35%. The method proposed in this paper has certain application potential in the CFETR power cable auxiliary monitoring system.
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Chen, Hui, Junjia Wang, Hejun Hu, Xiaofeng Li, and Yiyun Huang. "Aging Detection of 110 kV XLPE Cable for a CFETR Power Supply System Based on Deep Neural Network." Energies 15, no. 9 (April 25, 2022): 3127. http://dx.doi.org/10.3390/en15093127.
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To detect the aging of power cables in the TOKAMAK power supply systems, this paper proposed a deep neural network diagnosis model and algorithm for power cable aging, based on logistic regression according to the characteristics of different high-order harmonics generated by different aging parts of the power cable. The experimental results showed that the model has high diagnostic accuracy, and the average error is only 2.35%. The method proposed in this paper has certain application potential in the CFETR power cable auxiliary monitoring system.
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Klimenta, Jelena, Marija Panic, Miodrag Stojanovic, Dardan Klimenta, Milos Milovanovic, and Bojan Perovic. "Thermal aging management for electricity distribution networks: Fem-based qualification of underground power cables." Thermal Science, no. 00 (2022): 50. http://dx.doi.org/10.2298/tsci220128050k.
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It is well-known that there is no PLAN-DO-CHECK-ACT (PDCA) approach that is used by electricity distribution network operators and asset managers of power cable systems. Accordingly, this paper proposes a novel application of the PDCA approach to thermal aging management of underground power cables in electricity distribution networks. Another novelty of the proposed approach is that the finite element method (FEM) is used in combination with the traditional Arrhenius model to calculate the unknown temperature of cable conductors under service conditions. In particular, this means that the FEM-based Arrhenius model can involve the effects of other heat sources, wind, solar irradiation, etc. in procedures for qualification of underground power cables. The Arrhenius model is applied to an actual hot spot of a 110 kV underground cable line of most importance to reliable operation of the electricity distribution network of the City of Belgrade. In the hot spot, the 110 kV cable line is installed in parallel with the group of 35 kV cables and crosses an underground heating pipeline. The proposed approach is successfully validated using the existing experimental data on cross-linked polyethylene insulation. Finally, it is found that the hot spot effect can shorten the expected total service lifespan of the 110 kV cables in the hot spot area by 36.84 %, as well as that the largest consumption of total thermal lifespan occurs in the presence of all the existing thermal effects.
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Liu, Fan, Ping Liu, Lin Yang, Kai Zhou, and Wei Zhao. "Study of Siloxane Injection Technology on XLPE Cables for Water Tree Aging." Applied Mechanics and Materials 246-247 (December 2012): 1149–53. http://dx.doi.org/10.4028/www.scientific.net/amm.246-247.1149.
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This paper introduces one siloxane rejuvenation fluid used to rejuvenate aged XLPE cables and also studies the effects and the mechanism of the rejuvenation. Accelerated aging experiment was performed to obtain water tree aged samples. Inject the rejuvenation siloxane fluid into the aged cable samples with a pressure injection system. By comparing the dielectric loss factor and the breakdown voltage level of the samples before and after rejuvenation, inferred that the insulation level of the cable samples after rejuvenation is close to or higher than that of new cables. Additionally, through microscope, organic compounds created by chemical reaction were observed to fill the micro voids and eliminate the moisture in the XLPE layer of the samples. Finally, the electric field was simulated by Finite Element Method (FEM). Based on the results, it's further confirmed that the siloxane rejuvenation fluid can significantly enhance the aged cable insulation.
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Zhu, Guangya, Kai Zhou, Wei Gong, Min He, Jiaming Kong, and Kangle Li. "Inhibition of Rejuvenation Liquid on Trees in XLPE Cables under Switching Impulse Voltages." Energies 12, no. 11 (June 4, 2019): 2133. http://dx.doi.org/10.3390/en12112133.
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In this paper, the inhibitory effect of preinjected rejuvenation liquid on trees in cross-linked polyethylene (XLPE) cables was investigated. Experimental samples were prepared by inserting needles into XLPE samples, and many equally-spaced holes existed in the outer semiconductive layer. All cable samples were divided into two groups. One sample group was treated with rejuvenation liquid, while the other group was the control group. A tree accelerated aging system was used to obtain trees in the XLPE cable samples. During the aging experiment, an impulse voltage was applied to the samples repeatedly. The micromorphologies of the two groups were observed. Based on the micromorphologies, two parameters were determined: the initiation rate of electrical trees and the average length of trees. Furthermore, the electric field distribution was simulated to analyze the initiation of electrical trees. The results indicate that an electrical tree is much harder to initiate in the pretreated XLPE cables than in the untreated cables. This phenomenon is likely attributed to the dielectrophoretic forces in the pretreated cables. Moreover, rejuvenation liquid deposited in XLPE causes a substantial reduction in the Maxwell stress of molecular chains. Rejuvenation liquid inhibits electrical tree initiation and water tree growth to a great extent.
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Xu, Jiang, and Xin Jun Wu. "Nondestructive Testing of Bridge Cables Using Magnetostrictive Guided Wave Technique." Applied Mechanics and Materials 130-134 (October 2011): 2015–18. http://dx.doi.org/10.4028/www.scientific.net/amm.130-134.2015.
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Cables are used as critical structure components for suspended and cable-stayed bridges. It has been recently increased the need for inspection methods to assess the conditions of the cables due to owners concern about the operability and safety of such aging structures. An alternative technique is being developed in this paper. The magnetostrictive guided wave technology is used to test broken wires. The suitability of this method is studied through application tests on experimental setups, lab-made cables with simulated broken wires and field test. Test Results indicate that this technique can detect two broken wires away exceeding two meters and propagating over one hundred meters. It is a promising method for nondestructive testing of bridge cables.
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Ul-Hamid, Anwar, Khaled Y. Soufi, Luai M. Al-Hadhrami, and Ahsan M. Shemsi. "Failure investigation of an underground low voltage XLPE insulated cable." Anti-Corrosion Methods and Materials 62, no. 5 (September 7, 2015): 281–87. http://dx.doi.org/10.1108/acmm-02-2014-1352.
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Purpose – This paper aims to determine the effect of exposure of underground electrical cables to chemically contaminated water. Design/methodology/approach – Visual inspection and photography were carried out to record the appearance of electrical cables. Failed and un-failed cable samples were collected and analyzed using light microscopy, scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy. Sand and water samples were chemically tested for contaminants. Findings – Underground low-voltage 0.6/1-kV cross-linked polyethene insulated cables belonging to a chemical production plant suffered failure after four years of service. Excavation of the cable trench revealed that the cables were buried in sand polluted with chemically contaminated water. The cables were discolored and covered with corrosion deposits. Experimental results indicated that the cable insulation was heavily degraded and the outer jacket of polyvinyl chloride exhibited cracks that had penetrated through its thickness. Water and sand surrounding the cable were found to have high concentrations of ammonia. Mechanical testing of the cables indicated high values of stiffness that could contribute to the formation of cracks at the surface. Practical implications – It was concluded that contamination in the water had degraded the cable, resulting in the development of a network of branched cracks within the cable insulation through which water could permeate, leading to eventual failure of the cable. Accelerated degradation took place due to exposure to the contaminated environment, which promoted aging and brittleness. Continued exposure of electric cables to contamination would lead to power failures and plant shutdowns. Originality/value – This paper provides an account of a failure investigation of low-voltage electrical cable buried underground. It discusses the role of contaminated environment in the eventual failure of electrical cable due to corrosion. This information will be useful for plant engineers and project managers working in any industry that makes use of chemicals.
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Lee, Seok Hui, Min Ho Kim, Seung Yeon Jeong, Sang Kyu Lee, Ju Eun Lee, and Min Chul Lee. "Combustion Characterization according to Accelerated Deterioration Temperature of a Non-class 1E Cable." International Journal of Fire Science and Engineering 36, no. 1 (March 31, 2022): 19–29. http://dx.doi.org/10.7731/kifse.d86e802e.
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In this study, the temperature effect of accelerated deterioration on combustion characteristics was investigated when accelerating aging a non-class 1E cable for nuclear power plants. The accelerated aging of 40 years was conducted under five temperature conditions of 90 °C, 100 °C, 110 °C, 130 °C and 150 °C. In the early period of combustion when the first peak of the heat release rate emerged, the heat release of the non-aged cable exhibited the largest peak value of 225 kW/m2 while the heat release of the aged cables exhibited a comparatively low first peak value. The first peaks of aged cables decreased as the temperature condition increased. This tendency is considered to emerge from the thermal decomposition and destabilization of long-chained polymer structure when the sheath and insulation of cables are exposed to a thermal degradation environment. Hence, this loosening of the chemical bond and its decomposition severely affected the degradation of the flame retardant performance. In particular, in the combustion characteristics for the aged cables under temperature conditions of 100 °C or higher, the first peak value of the heat release rate did not exceed 200 kW/m2. In the middle period of combustion, the heat release rates of both the non-aged and the aged cables were kept constant at approximately 25-30 kW/m2 without significant change. In the later period of combustion, the second heat release peaks emerged for only non-aged, 90 °C and 100 °C cables because the cables aged under low temperature conditions (90 °C and 100 °C) maintained a certain level of flame retardant performance while those aged above 100 °C did not. Therefore, it can be considered that the higher accelerated deterioration temperature triggers the higher degradation of the flame retardant performance, and 100 °C is a critical temperature that involves the significant degradation effect.
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Meng, Xiaokai, Zhiqiang Wang, and Guofeng Li. "Life assessment of marine ethylene propylene rubber power cables based on hardness retention rate." Archives of Electrical Engineering 66, no. 3 (September 1, 2017): 475–84. http://dx.doi.org/10.1515/aee-2017-0035.
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AbstractThe lifetime of ethylene propylene rubber (EPR) insulated cables will decrease because of complex aging processes. From the safety perspective, insulation condition assessment of the cable is essential to maintain an efficient and reliable operation. As a nondestructive and online evaluation method, a hardness retention rate was used to estimate the lifetime of cable. First, accelerated thermal aging tests in the laboratory were performed to measure the elongation at break retention rate (EAB%) and a hardness retention rate at different temperatures. Second, the aging values were processed by the Arrhenius equation and time temperature superposition to assess aging lifetime of insulation at different temperatures and end levels. As the insulation condition assessment of the cable by hardness retention test has no approved standard, the EAB% data were correlated with hardness retention to provide an evaluation basis. The results show that when EAB% picks out the time corresponding to a certain amount of 50% degradation, 10% of hardness retention was chosen as the termination index.
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Afia, Ramy S. A., Ehtasham Mustafa, and Zoltán Ádám Tamus. "Aging Mechanisms and Non-Destructive Aging Indicators of XLPE/CSPE Unshielded LV Nuclear Power Cables Subjected to Simultaneous Radiation-Mechanical Aging." Polymers 13, no. 18 (September 8, 2021): 3033. http://dx.doi.org/10.3390/polym13183033.
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Low-voltage cable systems in nuclear power plants are key components that have a crucial role in the safe operation of nuclear facilities. Thus, the aging management of cable systems is of utmost importance as they cannot easily or economically be replaced or upgraded. Therefore, there is a continuous need to develop reliable non-destructive condition monitoring techniques, mostly based on the measurement of the dielectric properties of cable insulation. This paper introduces the changing of dielectric and mechanical properties of XLPE insulated and CSPE jacketed unshielded low-voltage nuclear power plant power cable in case of simultaneous mechanical and radiation aging. The cable samples were bent and exposed to 400 kGy gamma irradiation with a 0.5 kGy/hr dose rate. Dielectric response (real and imaginary permittivity) in the 0.1 Hz−1 kHz frequency range, extended voltage response (EVR), and the Shore D hardness test techniques were measured to track aging. The electrical and mechanical parameters have increased monotonically with aging, except the imaginary permittivity, which increased only at frequencies higher than 10 Hz. Furthermore, different quantities were deducted based on the frequency and permittivity data. The electrical parameters and deducted quantities correlation with aging and mechanical parameters were investigated. Since the deducted quantities and the electrical parameters are strongly correlated with absorbed dose and mechanical properties, the electrical measurements can be applied as a non-destructive aging indicator for XLPE/CSPE unshielded low-voltage nuclear power cables.
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Ni, Jing, Xu Ren, and Junqiang Zheng. "Friction and Wear Mechanism Analysis of Polymer Flexible Cable Using a High Natural Frequency Piezoelectric Sensor." Sensors 20, no. 4 (February 14, 2020): 1044. http://dx.doi.org/10.3390/s20041044.
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The friction and wear of flexible cables are the main factors that cause electrical breakdown and insulation aging, and they greatly reduce the reliability and safety of robots. In order to enhance the reliability and safety of the robot, it is of great necessity to investigate the friction and wear mechanisms of the flexible cable. In this research, the friction and wear mechanisms have been discussed. The effects of relative speed, ambient temperature, and positive pressure on the flexible cables are considered by an orthogonal frictional movement. The cable friction force has been measured by a piezoelectric sensor with high natural frequency characteristics. The relations among friction and different factors affecting friction have also been discussed. The results show that the relative speed and the ambient temperature are the main factors affecting the friction and wear of the cable; the main form of flexible cable wear is mechanical-force chemical friction and wear. Those discoveries will greatly deepen the understanding of the friction and wear mechanisms of flexible cables, and will be beneficial to robot cable-reliability design.
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Zhu, Zhao, Han, Wang, Wang, Liu, Xie, and Zhu. "Thermal Effect of Different Laying Modes on Cross-Linked Polyethylene (XLPE) Insulation and a New Estimation on Cable Ampacity." Energies 12, no. 15 (August 3, 2019): 2994. http://dx.doi.org/10.3390/en12152994.
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This paper verifies the fluctuation on thermal parameters and ampacity of the high-voltage cross-linked polyethylene (XLPE) cables with different insulation conditions and describes the results of a thermal aging experiment on the XLPE insulation with different operating years in different laying modes guided by Comsol Multiphysics modeling software. The thermal parameters of the cables applied on the models are detected by thermal parameter detection control platform and differential scanning calorimetry (DSC) measurement to assure the effectivity of the simulation. Several diagnostic measurements including Fourier infrared spectroscopy (FTIR), DSC, X-ray diffraction (XRD), and breakdown field strength were conducted on the treated and untreated specimens in order to reveal the changes of properties and the relationship between the thermal effect and the cable ampacity. Moreover, a new estimation on cable ampacity from the perspective on XLPE insulation itself has been proposed in this paper, which is also a possible way to judge the insulation condition of the cable with specific aging degree in specific laying mode for a period of time.
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Buev, S. A. "Analysis of XLPE cable parameters subject to thermo aging." Vestnik MGTU 24, no. 4 (December 30, 2021): 341–49. http://dx.doi.org/10.21443/1560-9278-2021-24-4-341-349.
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Modern marine vessels use electrically driven rudders; cruise liners, gas carriers, tankers are equipped with Azipod systems manufactured by the Swedish-Swiss company ABB. Gondola-type propellers make it possible to break ice when the vessel is moving astern, therefore such vessels are used for work on the Northern Sea Route, in particular, when working on the Yamal LNG project. The 22MW Azipod propulsion system rotates 360° and enables difficult maneuvering without the assistance of tugs. When operating such propellers, powerful diesel generators are installed on the ship. For the transmission of electricity, ship cables are used, which are subject to increased requirements that meet the standard of the International Electrotechnical Commission. Modern marine vessels are equipped with XLPE or EPDM insulated cable lines; industrial production of these cables is carried out in the Russian Federation. In the course of the study, a method for auditing the state of insulation has been considered based on an assessment of the change in the tangent of the angle of dielectric losses in the process of thermal aging of the cable of the PvBPng(A)-HF brand. Measurements of the tangent of the dielectric losses' angle have been carried out with a Tangens-2000 insulation parameter meter.
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Golovko, Sergey Vladimirovich, Julia Aleksandrovna Golovko, Maksim Almansurovich Nadeev, and Nikolay Gennadievich Romanenko. "Romanenko N. G. Increasing efficiency of ship cables defectation." Vestnik of Astrakhan State Technical University. Series: Marine engineering and technologies 2021, no. 4 (November 30, 2021): 98–106. http://dx.doi.org/10.24143/2073-1574-2021-4-98-106.
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The ship power supply system is a complex system that supplies electrical energy to various mechanisms and devices using wires and cables. The reliability of power supply largely depends on the technical condition of the cable lines. During operation, cable lines are regularly exposed to mechanical stress, both from external factors and from people. Some of the most common causes of cable damage are: aging insulation, overvoltage, thermal stress, boat vibration, and corrosion and moisture. Leaving the operating state of the cable line can lead to emergencies. A cable with damaged insulation can cause an electric arc with a metal object. If several phases of a cable with damaged insulation, then when they touch, a phase-to-phase short circuit occurs, as a result of which a large amount of heat is released, from which the cable insulation and other nearby combustible materials can ignite. There is considered the principle of operation of DIPCEL (a device for diagnosing ship cables) and shown its main disadvantages in determining the aging and moisture indicators of cable insulation. It is proposed to use the absorption coefficient for increasing the efficiency of measuring the ship’s cable insulation moisture. For insulating materials, in which the absorption current decreases rapidly, resistance measurements should be taken after 15 sec and 60 sec. The absorption coefficient is defined by measuring the ratio of a sixty-second insulation resistance to a fifteen-second resistance. If the value of the obtained coefficient is less than 1.25, then the insulation is unsatisfactory; if the value is within 1.25 - 1.6, than the insulation is normal, if more than 1.6 - the insulation is excellent
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Mustafa, Ehtasham, Ramy S. A. Afia, Aamir Nawaz, Oumaima Nouini, and Zoltán Ádám Tamus. "Implementation of Non-Destructive Condition Monitoring Techniques on Low-Voltage Nuclear Cables: II. Thermal Aging of EPR/CSPE Cables." Energies 15, no. 9 (April 28, 2022): 3231. http://dx.doi.org/10.3390/en15093231.
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Determining the aging state of low-voltage nuclear power plant cables using a nondestructive and reliable condition monitoring technique is highly desirable as the cables experience multiple aging stresses during the service period. This paper deals with the implementation and investigation of such nondestructive techniques, which can detect the overall aging state of low-voltage instrumentation and control (I&C) cables, which are subjected to accelerated thermal aging. The dielectric spectroscopy, extended voltage response, and polarization–depolarization current as nondestructive electrical aging techniques were used for the investigation purpose, while the elongation at break was also adopted as a mechanical measurement and for comparison. Prominent variations in the electrical parameters for the insulation and jacket were observed, whereas the elongation at break for both materials also decreased under thermal aging. Based on the electrical techniques, aging markers were selected that showed a strong correlation with the aging and elongation at break, proving the ability of the adopted electrical methods as a nondestructive condition monitoring technique.
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Kang, Sin-Dong, and Jae-Ho Kim. "Investigation on the Insulation Resistance Characteristics of Low Voltage Cable." Energies 13, no. 14 (July 13, 2020): 3611. http://dx.doi.org/10.3390/en13143611.
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This study evaluated the insulation resistance characteristics of TFR-8 (Tray Frame Retardant power cable for fire service) and VCTF (Light PVC Sheathed Circular Cord) cables under external flame, over-current, and accelerated degradation tests. In the accelerated degradation test of the cable, aging times of 10, 20, 30, and 40 years were tested according to a temperature derived using the Arrhenius equation. The insulation resistance of the TFR-8 cables was reduced from a maximum of 7.5 T ohm to 0.008 T ohm during the flame contact and recovered to its original state after cooling. However, dielectric breakdown occurred in the VCTF cable during flame contact and the cable did not return to its original state, even after cooling. In the forced convection oven test, the insulation resistance of the cable was reduced at 160 °C, whereas the insulation resistance of the cable was reduced at 125 °C in the over-current test. This result implied that the over-current had a greater impact than did heat applied externally on the degradation of the cable insulator. In the accelerated degradation tests from 10–30 years, the TFR-8 cable did not show any reduction in insulation resistance at room temperature. However, after an induced aging time of 40 years, the cable showed a rapid reduction in insulation resistance at room temperature.
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Ferry, Muriel, Floriane Carpentier, and Manon Cornaton. "Radio-Oxidation Ageing of XLPE Containing Different Additives and Filler: Effect on the Gases Emission and Consumption." Polymers 13, no. 17 (August 24, 2021): 2845. http://dx.doi.org/10.3390/polym13172845.
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In the lifetime extension of nuclear power plants (NPPs) context, aging of electric cables has to be very well understood in order to predict their end-of-life and thus to replace them on time. Therefore, evaluation and understanding of the ageing mechanism of the cable insulating material is mandatory under conditions as close as possible of those encountered in NPPs. In this context, different formulated crosslinked polyethylenes (XLPE)—one of the polymers used nowadays to manufacture the insulator layer—have been irradiated under oxidative conditions, at two different dose rates and at different aging doses. Gases emitted and consumed from the irradiated polymers were quantified to identify the primary processes happening in the materials and thus the interactions involved between the different molecules composing the formulated polymers.
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Rojas Rodríguez, Freddy Ignacio, José Roberto d’Almeida Moraes, and Bojan A. Marinkovic. "Natural Aging of Ethylene-Propylene-Diene Rubber under Actual Operation Conditions of Electrical Submersible Pump Cables." Materials 14, no. 19 (September 24, 2021): 5520. http://dx.doi.org/10.3390/ma14195520.
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Ethylene-propylene-diene monomer (EPDM) rubbers used in electric submersible pump (ESP) cables were analyzed after being aged in actual operation conditions in oil wellbores. These rubbers constitute the insulation and jacket layers of the ESP cables. EPDM rubbers from four different cables operating during different time intervals (2 and 4.8 years) at different depths (from 760 to 2170 m) below sea level were studied. To verify the effects of the long exposure on the rubber performance, thermal analysis was performed to determine the thermal stability and activation energy of degradation. In addition, structural analysis, through vibrational spectroscopy and crosslinking fraction assessment, was carried out. The mechanical properties of the aged rubbers were inferred through the measurement of hardness, while the absorption of a service fluid was studied by gravimetry. The results showed only minor changes in the thermal, structural, mechanical and barrier properties of the EPDM-based ESP cable layers. It is suggested that the thermo-oxidation mechanism followed by chain scission does not have a role in the degradation of EPDM within the aged ESP cables, and no sign of variation of crosslink fractions has been encountered. Therefore, it was concluded that EPDM-based layers seem not to be weak links in the configuration of modern ESP systems.
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Abro, Shahid Hussain, Syed Aqeel Ahmed Shah, Abdulaziz Solaiman Alaboodi, and Talha Shoaib. "Ageing Analysis of Power Cable used in Nuclear Power Plant." January 2020 39, no. 1 (January 1, 2020): 195–204. http://dx.doi.org/10.22581/muet1982.2001.18.
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The aim of nuclear power plant ageing management and assessment is to maintain an adequate safety level throughout the life time of the plant and helps in determining the useful operation. Various factors involved in the insulation of polymeric cables such as continuous heat, radiation and atmosphere result in the alteration of chemical and physical properties as well as lowers the service life of material. PVC (Poly Vinyl Chloride) is the most commonly used insulation material in NPP (Nuclear Power Plant). Purpose of this work is to predict the service life of PVC insulation cable for which extrapolation ageing has been performed. Ageing mechanism proceeds in laboratory scale rig to provide temperature and radiation sources. The variation in temperature is regulated and monitored through thermocouple. At higher temperature, semi crystalline free radical may escape out resulting in the degradation of polymer. Different tests have been carried out like shore hardness testing, tensile testing, Differential Scanning Calorimeter and Thermo gravimetric Analysis before and after ageing to analyze the Ageing effect. The impact of ageing days upon yield strength of single stress ageing has been carried out in this research work and it is found that aging has significant effect on service life of cables used in power plants.
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Mustafa, Ehtasham, Ramy S. A. Afia, Oumaima Nouini, and Zoltán Ádám Tamus. "Implementation of Non-Destructive Electrical Condition Monitoring Techniques on Low-Voltage Nuclear Cables: I. Irradiation Aging of EPR/CSPE Cables." Energies 14, no. 16 (August 20, 2021): 5139. http://dx.doi.org/10.3390/en14165139.
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In a nuclear power plant environment, low-voltage cables experience different stresses during their service life which challenge their integrity. A non-destructive and reliable condition monitoring technique is desired to determine the state of these low-voltage cables during service and for the life extension of nuclear power plants. Hence, in this research work, an EPR/CSPE-based low-voltage cable was exposed to γ-rays for five different absorbed doses. The overall behavior of the cable under stress was characterized by frequency and time domain electrical measurements (capacitance, tan δ, and Extended Voltage Response) and a mechanical measurement (elongation at break). Significant variations in the electrical parameters were observed, as was a decline in the elongation at break values. A strong correlation between the measurement methods was observed, showing the ability of the electrical methods to be adopted as a non-destructive condition monitoring technique.
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Madrakhimov, Daniyar Bakhtiyarovich, Vera Pavlovna Ivanova, and Victoria Vyacheslavovna Tsypkina. "Improving the reliability of cable lines operation in hot climates." E3S Web of Conferences 216 (2020): 01151. http://dx.doi.org/10.1051/e3sconf/202021601151.
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Reliability of cable lines in hot climate is determined by the climatic characteristics of cables and wires, which include: long-term and short-term heat resistance, cold resistance, moisture resistance, resistance to cyclic exposure to temperatures and solar radiation, ozone resistance, etc. This article considers the main impacts of environmental factors: high temperatures, solar radiation, which, as practice shows, lead to irreversible deterioration of the electrical and mechanical properties of cable products. The result of climatic impacts in the Central Asian region, in hot climate conditions, is the aging of both insulation and protective coverings, which leads to irreversible change in the mechanical and electrical properties of the used polymers due to the loss of elasticity of the extruded material and its subsequent cracking, turning into cracks. The assessment of the possibility of long-term operation of the used polymer was carried out according to the polyethylene oxidation period, which determines the time of natural preservation of various types of cables during the period of their operation. The research was carried out on samples of cables stored under a canopy in wooden boxes, protected from sunlight and precipitation, by measuring criterion parameters with strict compliance with the established norms. Thus, the proposed solution for increasing the reliability of cable lines consists of debugging the technological process of applying insulation and sheathing, in which the extrusion of the polymer mass is carried out by technique that minimizes the ingress of contamination. Review of the results showed that extrusion line improvement would provide possibility of increasing reliability in the operation of cable products under the impact of climatic factors of the Central Asian region due to the reduced aging of insulation.
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Guo, Jin Ming, and Fei Feng Wang. "Influence of Cable Temperature Rise on PDC Method Test Results of Water Tree Aged Cables." E3S Web of Conferences 261 (2021): 01025. http://dx.doi.org/10.1051/e3sconf/202126101025.
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There is a certain temperature rise in the field running cable because of the load bearing. To study the influence of cable temperature rise on the polarization and depolarization current (PDC) method, 10kV XLPE short cables were accelerated aging three months by water needle electrode method, and the PDC method was used to test the new and aged cables under constant humidity. The polarization and depolarization current of the cable samples was analyzed, and the conductivity and low frequency dielectric loss spectra were obtained and inspected. The results show that: in the experiment selected test temperature, the change laws of conductivity of the new and aged cables are the same, and the conductivity gradually rose after a slight drop in 40 °C; in the dielectric loss spectrum, the polarization of the new sample is low and the polarization loss changes little with temperature, and the dielectric loss is mainly affected by the conductivity, so the test result is clearly divided into two regions. And water tree aged samples have strong polarization and are obviously affected by temperature, so their low frequency dielectric loss showed the trend of first rising and then decreasing and the maximum appeared at 60 °C.
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Suraci, Simone Vincenzo, and Davide Fabiani. "Aging Modeling of Low-Voltage Cables Subjected to Radio-Chemical Aging." IEEE Access 9 (2021): 83569–78. http://dx.doi.org/10.1109/access.2021.3086987.
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Jang, Kyung Nam, Jong Soeg Kim, Sun Chul Jeong, Kyung Heum Park, and Sung Yull Hong. "Analysis of the Degradation Tendency of NPP Cables Using a Wireless Cable Indenting Robot." Applied Mechanics and Materials 284-287 (January 2013): 1749–53. http://dx.doi.org/10.4028/www.scientific.net/amm.284-287.1749.
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In nuclear power plants, there are many cables that perform safety-related functions. These cables should implement condition monitoring during the operation period in the nuclear power plant, in order to assess the remaining qualified life and extend the qualified life. In this study we focused on the indenting method which can measure the hardness of the cable jacket. This method is selected because it is non-destructive and requires short testing time and small sized equipment. In order to address the problems with the existing indenting test equipment, we developed new indenting test equipment, which could automatically move on the surface of the object cable. The newly developed equipment is designed for a small-sized and light-weight robot using wireless communication in order to implement condition monitoring in a harsh environment or locations that are inaccessible to the tester. The developed wireless cable indenting robot is composed of three parts, which are mechanical and electrical hardware parts and remote-control part. In order to analyze the degradation tendency of the cable, we prepared four thermally aged specimens and one un-aged specimen. Using the developed robot, we measured the modulus of the cable jacket of each specimen. The test data showed that the modulus of the cable jacket increased linearly as the accelerated aging time increased. From these results, we can analyze the degradation trends pertaining to cables installed in nuclear power plant according to the operation period.
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Verschaffel-Drefke, Christoph, Markus Schedel, Constantin Balzer, Volker Hinrichsen, and Ingo Sass. "Heat Dissipation in Variable Underground Power Cable Beddings: Experiences from a Real Scale Field Experiment." Energies 14, no. 21 (November 2, 2021): 7189. http://dx.doi.org/10.3390/en14217189.
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To prevent accelerated thermal aging or insulation faults in cable systems due to overheating, the current carrying capacity is usually limited by specific conductor temperatures. As the heat produced during the operation of underground cables has to be dissipated to the environment, the actual current carrying capacity of a power cable system is primarily dependent on the thermal properties of the surrounding porous bedding material and soil. To investigate the heat dissipation processes around buried power cables of real scale and with realistic electric loading, a field experiment consisting of a main field with various cable configurations, laid in four different bedding materials, and a side field with additional cable trenches for thermally enhanced bedding materials and protection pipe systems was planned and constructed. The experimental results present the strong influences of the different bedding materials on the maximum cable ampacity. Alongside the importance of the basic thermal properties, the influence of the bedding’s hydraulic properties, especially on the drying and rewetting effects, were observed. Furthermore, an increase in ampacity between 25% and 35% was determined for a cable system in a duct filled with an artificial grouting material compared to a common air-filled ducted system.
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Bezprozvannych, G. V., I. O. Kostukov, and E. S. Moskvitin. "DIFFERENTIATION OF ABSORPTION PROCESSES IN INHOMOGENEOUS INSULATION BY CURVE OF RECOVERING VOLTAGE OF POWER HIGH VOLTAGE CABLES." Tekhnichna Elektrodynamika 2021, no. 6 (October 21, 2021): 13–19. http://dx.doi.org/10.15407/techned2021.06.013.
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Based on the proposed model of spatially inhomogeneous two-layer insulation in the form of a series-parallel substitution scheme with three relaxation chains, the calculated recovery voltage curves of phase and belt paper-impregnated insulation of power cables are obtained. The model was verified by comparison with the experimental voltage curve of the power cable with paper-impregnated insulation at a voltage of 6 kV. The possibility of separation of delayed absorption processes in inhomogeneous insulation is substantiated on the basis of the analysis of high-frequency components of the spectrum of time dependences of the recovery voltage curves. The effectiveness of wavelet transform for detailing the absorption characteristics of inhomogeneous insulation of power cables is confirmed. The presence of two maxima and the dynamics of change of the ratio between them in the process of aging of inhomogeneous insulation on the reproducible curves of the regenerative voltage of power cables are established. Based on the relationship between the two amplitude values of the reproducible reduction voltage, the preferred absorption processes are determined and the appropriate criteria for assessing the state of inhomogeneous insulation of power cables are established. References 16, figure 5.
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Agustin, Fernando, Akhtar Kalam, and Aladin Zayegh. "Investigation of 22 kV silane cure TR-EPR cable." International Journal of Applied Power Engineering (IJAPE) 10, no. 1 (March 1, 2020): 41. http://dx.doi.org/10.11591/ijape.v10.i1.pp41-47.
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EPR-insulated cables for distribution power network are not commonly used in Australia. This is due to the higher DDF of common EPR cables when compared with XLPE that contributes to the power loss and economics in transmitting electricity. This led to the development of EPR called TR-EPR with significantly lower DDF and uses silane curing process to address concerns about cost-effectiveness. The thermal behavior of low DDF silane cure TR-EPR is investigated for 30 months of exposure to the maximum operating temperature of material. The physical changes in the samples throughout the long-term aging are examined to create an opportunity to model the expected life cycle of TR-EPR cable under thermal stress. The cross-linking characteristics of TR-EPR cable are also examined by ambient curing that simulates the storage condition for unused cable and by cable heating process that simulates the condition when the cable is energized. The results are tabulated for a better understanding of the time for the material to cross-link at various conditions. The improved partial discharge values after cross-linking are also presented.
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Zhang, Yi, Zaijun Wu, Cheng Qian, Xiao Tan, Jinggang Yang, and Linlin Zhong. "Research on Lifespan Prediction of Cross-Linked Polyethylene Material for XLPE Cables." Applied Sciences 10, no. 15 (August 4, 2020): 5381. http://dx.doi.org/10.3390/app10155381.
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In this paper, cross-linked polyethylene (XLPE) cables of the same batch from Factory A, which ran from 1 to 8 years in Jiangsu Province, are sampled. Some widely accepted aging characterization methods of XLPE cables such as the gel content test, differential scanning calorimetry (DSC) test, tensile test and hardness test are employed to obtain the physicochemical, mechanical and electrical properties of the samples. Then, some lifespan prediction parameters significantly correlated with operating time are obtained through correlation calculations. Finally, a prediction method is proposed to predict the operating time of XLPE cables from Factory A. The test results indicate that parameters including the gel content Cge, the crystallinity XC, tensile strength σ, ultimate elongation δ, the dielectric permittivity ε, and the dielectric loss Jtan are significantly correlated with operating time, which can be used in evaluating the aging degree of XLPE cables. Moreover, due to the high accuracy of the experimental verification, it turns out that the lifespan prediction method proposed in this paper can be used to determine the operating time of XLPE cables from Factory A in future research.
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Polyakov, D. A., M. A. Kholmov, D. I. Plotnikov, K. I. Nikitin, and U. V. Polyakova. "Mathematical modeling of service life of cables polymer insulation." Omsk Scientific Bulletin, no. 174 (2020): 69–73. http://dx.doi.org/10.25206/1813-8225-2020-174-69-73.
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The studies of the service life and residual life of various insulating materials are described. The known mathematical models of insulation aging applicable to AC power cable lines are considered. Based on the models and the previously proposed approach, the service life and residual life of cables with XLPE, EPR and PVC insulation are estimated. The assessment is carried out using the data from monitoring the voltage and current of a 6 kV cable transmission line laid at one of the electric power enterprises. Air temperature obtained from open sources. The results showed the applicability of all models for estimating the residual life due to the small difference in the predicted life. In real conditions, the service life of the listed types of insulation can be different due to their dielectric and design features
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Mayoux, C. "Aging of polymeric insulating materials in power cables." IEEE Transactions on Dielectrics and Electrical Insulation 4, no. 6 (1997): 665–73. http://dx.doi.org/10.1109/94.654573.
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Csányi, Gergely Márk, Semih Bal, and Zoltán Ádám Tamus. "Dielectric Measurement Based Deducted Quantities to Track Repetitive, Short-Term Thermal Aging of Polyvinyl Chloride (PVC) Cable Insulation." Polymers 12, no. 12 (November 27, 2020): 2809. http://dx.doi.org/10.3390/polym12122809.
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The effect of short-term (3- and 6-h-long) periodic thermal aging was investigated at three different temperatures on PVC cables and PVC films. Three different temperatures (110, 125, and 140 °C) were used for aging PVC cables and one (110 °C) for PVC films. PVC films were prepared for the investigation containing 0, 30, 40, and 50 weight percent of dioctyl phthalate plasticizer (DOP). The effect of short-term thermal aging was monitored by electrical (dielectric spectrum and voltage response measurement) and mechanical (Shore D hardness) methods. From the loss factor measurements, different deducted quantities were calculated and compared with Shore D hardness, which has been shown to be a parameter reflecting the effect of short-term thermal aging on PVC insulation. The measurements revealed that Shore D hardness is not the best property for monitoring aging. Instead, increasing dissipated power and the shifting behavior of tan δ–frequency curves proved to be the best phenomena for assessing the impact of thermal aging. Simple deducted quantities may provide a basis for following short-term thermal aging.
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Mustafa, Ehtasham, Ramy S. A. Afia, and Zoltán Ádám Tamus. "Condition Assessment of Low Voltage Photovoltaic DC Cables under Thermal Stress Using Non-Destructive Electrical Techniques." Transactions on Electrical and Electronic Materials 21, no. 5 (May 15, 2020): 503–12. http://dx.doi.org/10.1007/s42341-020-00201-3.
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Abstract The output power of the photovoltaic system is heavily dependent on the low voltage (LV) DC cables which are exposed to multiple stresses such as climatic, mechanical, electrical, and thermal stress, hence makes them more exposed to aging as compared to other components in the system. Accordingly, it is essential to monitor the state and know the real cause of the insulation degradation of the cable. The physio-chemical changes inside the insulation during service is attributed to the thermal stress, which the cable has to endure constantly. Traditionally, destructive test techniques have been adopted to study the aging phenomenon in the cable insulation, making them unsuitable for on-line condition monitoring. This research work has been aimed to study the degradation in LV photovoltaic DC cables under thermal stress by measuring the dielectric properties; complex permittivity, tanδ with the change in frequency and decay and return voltage slopes using extended voltage response method. The non-destructive diagnostic methods used are based on the phenomenon of polarization and conduction in the insulation material. The noteworthy change in the values of the imaginary part of permittivity, tanδ at low frequencies, and the overall decrease in the values of return voltage slope showed the change in the structure of the polymer matrix under the stress which was related to the cross-linking based chemical reactions. The results show that the techniques can be adopted for the on-line condition monitoring of the cable for the PV system and the dielectric parameters can be used to study the chemical and physical changes happening inside the material effectively.
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Oh, Dong-Hun, Ho-Seung Kim, and Bang-Wook Lee. "A Novel Diagnosis Method for Void Defects in HVDC Mass-Impregnated PPLP Cable Based on Partial Discharge Measurement." Energies 14, no. 8 (April 7, 2021): 2052. http://dx.doi.org/10.3390/en14082052.
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Mass Impregnated PPLP cable, which is applied to various high-voltage direct current (HVDC) projects due to its excellent dielectric and temperature properties, has a problem wherein voids are formed inside the butt-gap due to cavitation. However, there has been no previous research into technology for void defect identification and insulation diagnosis on HVDC MI-PPLP cables. In this paper, to propose an insulation diagnosis method for void defects in HVDC MI-PPLP cable, the direct current (DC) void discharge patterns were analyzed according to the specimen temperature and the magnitude of applied voltage using the pulse sequence analysis method. In addition, to confirm the pre-symptoms of dielectric breakdown in MI-PPLP cable due to DC void discharge, partial discharge patterns were analyzed continuously until dielectric breakdown occurred. From the experimental results, DC void discharge patterns of the same shape were obtained regardless of the specimen temperature and the magnitude of applied voltage. In addition, it was confirmed that new insulation aging patterns were generated as electrical and thermal aging occurred due to the continuous DC void discharge. Therefore, it is demonstrated that identification and insulation diagnosis of void defects in HVDC MI-PPLP cable is possible through the obtained DC void discharge and insulation aging patterns.
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Choudhary, Maninder, Muhammad Shafiq, Ivar Kiitam, Amjad Hussain, Ivo Palu, and Paul Taklaja. "A Review of Aging Models for Electrical Insulation in Power Cables." Energies 15, no. 9 (May 6, 2022): 3408. http://dx.doi.org/10.3390/en15093408.
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Electrical insulation is an integral part of power components. The aging of electrical insulation is an undeniable fact that limits the operational lifetime of power components. Apart from regular aging, abnormal stresses and the development of defects are real threats because of their contribution in accelerating the aging rate and thereby leading to a premature failure of the power components. Over the decades, various studies have been carried out to understand the aging behavior of electrical insulation mainly considering electrical and thermal stresses. Similarly, a number of mathematical (aging) models have been developed based on the theoretical and experimental investigations and evidences. However, a dependable formulation of the models that can provide more practical estimation of the insulation degradation profile has not been achieved yet. This paper presents a comprehensive review of the aging models considering single and multistress conditions. Further, the paper discusses possible challenges and barricades averting the conventional models to achieve a suitable accuracy. Finally, suggestions are provided that can be considered to improve the modeling approaches and their performance.
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Pleşa, Ilona, Petru Noţingher, Cristina Stancu, Frank Wiesbrock, and Sandra Schlögl. "Polyethylene Nanocomposites for Power Cable Insulations." Polymers 11, no. 1 (December 24, 2018): 24. http://dx.doi.org/10.3390/polym11010024.
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This review represents a comprehensive study of nanocomposites for power cables insulations based on thermoplastic polymers such as polyethylene congeners like LDPE, HDPE and XLPE, which is complemented by original results. Particular focus lies on the structure-property relationships of nanocomposites and the materials’ design with the corresponding electrical properties. The critical factors, which contribute to the degradation or improvement of the electrical performance of such cable insulations, are discussed in detail; in particular, properties such as electrical conductivity, relative permittivity, dielectric losses, partial discharges, space charge, electrical and water tree resistance behavior and electric breakdown of such nanocomposites based on thermoplastic polymers are described and referred to the composites’ structures. This review is motivated by the fact that the development of polymer nanocomposites for power cables insulation is based on understanding more closely the aging mechanisms and the behavior of nanocomposites under operating stresses.
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Park, Kyung Hun, Hoon Cho, and Soong Keun Hyun. "The Effects of Aging Treatment on the Strength and Conductivity of Cu-Ag-Zr-Co Alloy." Materials Science Forum 695 (July 2011): 477–80. http://dx.doi.org/10.4028/www.scientific.net/msf.695.477.
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The development trend for diagnostics is reducing the diameter of coaxial signal cables that comprise the probe cable. The thinner super-fine coaxial cable which is offering superior electronic and mechanical properties, such as 75 %IACS(International Annealed Copper Standard, electrical conductivity) and 700 ~ 800 MPa in tensile strength has to be developed. Cu-Ag based system is one of the most promising systems for high strength and high conductivity Cu alloys. In order to find the optimum conditions to obtain Cu-Ag-Zr-Co alloy with high strength and high electrical conductivity, the aging characteristics including work hardening of micro-Vickers hardness, tensile strength and electrical conductivity of this alloy were systematically measured at room temperature. Also the influence of aging treatment was investigated by transmission electron microscopy(TEM) and scanning electron microscopy(SEM) in this study. The aging treatment for precipitation was divided into two steps and carried out at various time and at different temperature and the multi-step aging treatment coupled with cold rolling was proposed for realizing Cu-Ag-Zr-Co alloys with high strength and high electrical conductivity. The electrical conductivity was improved from 31 %IACS to 91 %IACS remarkably and the tensile strength was increased from 230Mpa to 690Mpa greatly by an optimization of alloy composition and manufacturing process including aging.
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Vlasov, A. B., and S. A. Buev. "The estimation of ship cable condition by the means of measuring its insulation characteristics." Vestnik MGTU 23, no. 4 (December 28, 2020): 335–44. http://dx.doi.org/10.21443/1560-9278-2020-23-4-335-344.
Full textAbstract:
Timely detection of defects in electrical equipment and cable network is required for the ensuring the fire safety of a modern marine vessel. The method of continuous monitoring of the resistance value of cable insulation is not very informative and is not applicable for assessing the service life of cables and predicting their replacement during operation and repair. Currently the problem of developing modern non-destructive methods of insulation control is very urgent in order to determine the operability of the cable, search for diagnostic parameters characterizing the state of insulation during prolonged aging, as well as the introduction of traditional methods of diagnostics of electrical equipment that have shown their effectiveness at the facilities of the coastal infrastructure. A promising solution for this problem is a method for monitoring the values of the tangent of the dielectric loss angle tgδ of cable insulation using devices that allow registering parameters with high accuracy. In this study the determination of changes in the parameters of a ship cable subjected to accelerated thermal aging at temperatures 120-130 °C has been made. The tgδ measurements of the cable sheath have been carried out using the Tangent-2000 insulation meter. The tests have shown that aging of cable hose insulation is accompanied by a non-linear change in tgδ; at certain values of the tangent of dielectric loss angle, visible cracks appear indicating the onset of an emergency condition of the cable. The nature of the change in the parameter tgδ is explained by the occurrence of reactions of oxidative dehydrochlorination of polychloroprene in the process of thermal aging of insulation and changes in its mass. Thus, the tangent of the dielectric loss angle can be one of the diagnostic parameters for assessing the state of the insulation of the ship's cable and predicting its service life.
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Gunes, Ibrahim. "Examination of Wind Effect on Adss Cables Aging Test." Electrica 18, no. 2 (July 29, 2018): 321–24. http://dx.doi.org/10.5152/iujeee.2018.1818.
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