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Meena, K. P.
- Ampacity of bundled PVC house wiring cables in a conduit pipe based on experimental and theoretical considerations
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Affiliations
1 Diagnostic, Cables and Capacitors Division, Central Power Research Institute, Bangalore-560 080, IN
1 Diagnostic, Cables and Capacitors Division, Central Power Research Institute, Bangalore-560 080, IN
Source
Power Research, Vol 10, No 4 (2014), Pagination: 723-730Abstract
Flexible PVC Cables form the major part of Power distribution system within residential buildings, industrial buildings, and other commercial institutions. The ampacity of power cable depends upon the cross sectional area of conductor and the laying and installation of the cable in service. Generally two or more number of PVC cables are bundled together and inserted as a bundle in a conduit pipe for connecting to various load points. As the bundling of cables produce more heat than a single PVC Cable, and dissipation of heat is poor, the ampacity of these cables reduces considerably. Hence the exact selection of sizes and no. of cables are essential to avoid overheating of those cables and the resulting fire havocs.PVC House wiring cables consists of copper conductor extruded with PVC insulation and are installed generally through a conduit pipe in a bundled manner. The steady state current rating of these cables depends on the way the heat generated in the cable due to current and the heat transmitted to the cable surface & then dissipated to the surroundings. The maximum conductor temperature is limited by the type of insulating material used. In this paper theoretical and experimental results of steady state ampacity ratings of bundles of house wiring PVC Cables laid in conduit pipes are compared.
Keywords
Ampacity, house wiring cables- Recent Advances in HV and EHV Power Cable Technology - CPRI’s Experience in Qualifi cation Tests on Power Cables
Abstract Views :191 |
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Authors
Affiliations
1 Central Power Research Institute, Bangalore-560080, IN
1 Central Power Research Institute, Bangalore-560080, IN
Source
Power Research, Vol 8, No 4 (2012), Pagination: 251–262Abstract
Over the years both due to demand and technological advancements there has been a continuous transition from smaller operating voltages of 6.6. kV to higher voltages of 500 kV. The conventional technology like taping or fi eld moulding are in vogue and new technology like pre-moulded slip on cable accessories are gaining importance for jointing of polymeric high voltage cables up to voltages of 500 kV. The fl ammability characteristics of polymeric materials used in cable insulation and jacketing have been of great importance over the years. Evaluation techniques have become more stringent and both short term and long term tests are conducted in order to ensure the quality of materials used, the manufacturing processes, workmanship and reliability. In this paper the recent advances in HV and EHV power technology is summarized and the experiences in testing and evaluation of 220 kV cables is presented and discussed.Keywords
Taping, Pre-moulded slip, High voltage (HV), Extra high voltage (EHV) polymeric cables.- Flame Retardancy of Instrumentation and Control Cables – CPRI’s Experience
Abstract Views :231 |
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Authors
Affiliations
1 Central Power Research Institute (CPRI), Bengaluru – 560080, Karnataka, IN
1 Central Power Research Institute (CPRI), Bengaluru – 560080, Karnataka, IN
Source
Power Research, Vol 14, No 2 (2018), Pagination: 121-125Abstract
In this paper the fire and smoke properties of special application cables such as instrumentation cables, control cables, fibre optic cables and flat travelling cables are compared for their better fire performance. The various outer sheath materials of these cables have been evaluated for its fire performance and as well as smoke performance. In case of zero halogen outer sheath materials of special application cables, only the smoke property is given importance and the fire retardant properties are not being given much importance. Hence the significance of fire retardant property is highlighted in this study.Keywords
Flammability, Halogen, Instrumentation Cable, Smoke Release, LSZHReferences
- Arunjothi R, Jayakrishnan M, Nageshwar Rao B. Characterization and analysis of cable and accessories materials,9th International Conference on Power Cables “CABLETECH-2017”.
- Rao BN, Arunjothi R. Lethal Combustion product evaluation of polymeric materials used in power cables, 9th International Conference on Insulated Power Cables, Jicable’15-21-25 June 2015.
- Nageshwar Rao B, Arunjothi R, Srinivasan AR. Assessing Smoke and Fire Hazard of Burning Electric Cables, IEEE10th International Conference on the Properties and Application of Dielectric Materials, ICPADM 2012.
- Condition Assessment Techniques for Insulation Diagnosis of Oil Filled Power Transformers
Abstract Views :220 |
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Authors
Affiliations
1 Central Power Research Institute (CPRI), Bengaluru – 560080, Karnataka, IN
1 Central Power Research Institute (CPRI), Bengaluru – 560080, Karnataka, IN
Source
Power Research, Vol 14, No 2 (2018), Pagination: 126-131Abstract
Power transformers are key components in the substation/switchyard and failure of transformer can have an enormous impact on reliability and availability of power supply and has financial implications. As there is ever increase in demand of power, the reliability of power equipment assumes high importance. Economic factors are the main consideration and in order to minimize capital expenditure on new equipment, it is a common policy among utilities to maximize the use of existing power transformers by operating at their design capability. This can be achieved by periodic diagnostic testing and adopting condition based maintenance practices. In this paper various condition assessment techniques for oil filled transformers are discussed and few case studies are presented.Keywords
Condition Assessment, Generator Transformer, Insulation Diagnosis, SFRAReferences
- Chakravorti S, Dey D, Chatterjee B. Recent trends in the condition monitoring of transformers-theory, implementation and analysis.
- IEEE Std. 62-1995 IEEE guide for diagnostic field testing of electric power apparatus-Part1 oil filled transformers, regulators and reactors. IEEE Xplore Digital Library; 1995 Dec 1.
- IEC Std. 60076-18, power transformer Part-18: Measurement of frequency response. International Electrotechnical Commission (IEC); 2012 Jul.
- Lifetime Evaluation of transformers. CIGRE Working Group 12.09; 1993.
- Pradhan MK, Ramu TS. On estimation of elapsed life of oil-immeresed power transformers. IEEE Transactions on Power Delivery. 2005; 20(3):1962–9.
- Field Testing and Condition Assessment of MV Power Cable System by Very Low Frequency (VLF) AC Testing
Abstract Views :313 |
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Authors
Affiliations
1 Cables and Diagnostics Division, Central Power Research Institute, Bangalore – 560080, Karnataka, IN
1 Cables and Diagnostics Division, Central Power Research Institute, Bangalore – 560080, Karnataka, IN
Source
Power Research, Vol 16, No 2 (2020), Pagination: 187-192Abstract
A huge capital investment goes for power cables in an electric power system. Reliability and life expectancy of serviceaged power cables can be assured by systematic field testing and condition assessment program. Very Low Frequency (VLF) ac Testing proved effective for field testing and condition assessment of shielded Power Cable System. Central Power Research Institute (CPRI), Bengaluru, a premier institute for Indian Power Sector has been conducting diagnostic testing on medium voltage power cable systems to assess the healthiness of the power cable systems and cable system components. In this paper application of VLF testing for withstand and other diagnostic tests and measurements are discussed. Few case studies based on the data obtained from the field testing on MV Power Cable System are presented.Keywords
Very Low Frequency (VLF), VLF Dielectric Spectroscopy (VLF-DS), VLF Differential Tangent Delta (VLF-DTD), VLF Monitored Withstand Test (VLF-MW), VLF Partial Discharge (VLF-PD),VLF Tangent Delta (VLF-TD), VLF Tangent Delta Temporal Stability (VLF-TDTS).References
- Puhan DK, Keri CD, Rao BN. CPRI experience in diagnostic testing and condition assessment of medium voltage power cable system.
- Mallikarjunappa K, Ramaprasath S, Keri CD, Sudhindra A. CPRI, Bangalore, Very low frequency tan delta testing and condition assessment of medium voltage polymeric cables.
- IEEE Std 400.2TM-2013, IEEE guide for field testing of shielded power cables using very low frequency (less than 1Hz).
- Thermal Lifetime Estimation of EVA Encapsulants from Activation Energy based Method
Abstract Views :77 |
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Authors
Affiliations
1 Cable and Diagnostics Division, Central Power Research Institute, Bangalore – 560080, Karnataka, IN
1 Cable and Diagnostics Division, Central Power Research Institute, Bangalore – 560080, Karnataka, IN
Source
Power Research, Vol 17, No 1 (2021), Pagination: 13-16Abstract
A rapid test method based on a logarithmic degradation model for the lifetime assessment of ethylene-vinyl acetate (EVA) used as encapsulants in Photovoltaic (PV) module is proposed. In general, encapsulants are used in widely varied conditions. However, factors such as voltage stress, irradiation, mechanical shock and vibration, environmental conditioning and chemical contamination should be evaluated. In the present study evaluation is carried on the dumbbell specimens of encapsulating material itself and is based on the percentage of reduction in the property i.e elongation percentage, which is a destructive test. Dumb-bell specimens as per ISO 37:2011(E) standard are employed. Adequate number of test specimens were subjected to thermal aging at three different temperatures 35 °C, 45 °C and 55 °C. The conditioned specimens after removing from oven were stored in decicator prior to testing i.e. while the specimens were attaining room temperature. The constant factors of the life time line a and b were calculated, and finally, the lifetime values were estimated.Keywords
: Elongation Percentage, Ethylene-Vinyl Acetate (EVA), Lifetime Estimation, Photovoltaic Solar CellReferences
- King DL, Quintana MA, Kratochvil J, Ellibee D, Hansen B. Photovoltaic module performance and durability following long- term field exposure. Progress in Photovoltaics: Research and Applications; 2000; 8:241–56. https://doi.org/10.1002/(SICI)1099-159X(200003/04)8:2<241::AIDPIP290> 3.0.CO;2-D
- BGI Research, Ethylene vinyl acetate (EVA) global market to 2015 - photovoltaic encapsulants to drive EVA demand in the future; 2011.
- Agroui K, Maallemi A, Boumaour M, Collins G, Salama M. Thermal stability of slow and fast cure EVA encapsulant material for photovoltaic module manufacturing process. Solar Energy Materials and Solar Cells. 2006; 90(15):2509– 14. https://doi.org/10.1016/j.solmat.2006.03.023
- Cuddihy E, Carroll W, Coulbert C, Gupta A, Liang R. Photovoltaic encapsulation design and material selection; 1982. https://doi.org/10.2172/5356871
- IEC 60216-1:2013, Electrical insulating materials - Thermal endurance properties - Part 1: Ageing procedures and evaluation of test results.
- IEC 60216-3:2006, Electrical insulating materials - Thermal endurance properties - Part 3: Instructions for calculating thermal endurance characteristics
- Fire-Resistant Cables- Heat Release Measurements
Abstract Views :67 |
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Authors
Affiliations
1 Central Power Research Institute, Bangalore - 560080, Karnataka, IN
1 Central Power Research Institute, Bangalore - 560080, Karnataka, IN
Source
Power Research, Vol 18, No 1 (2022), Pagination: 1-7Abstract
Fire Resistant cables are designed to maintain the circuit integrity of the cable even during fire conditions. In general, the fire-resistant cables are made up of flame retardant zero halogen materials, so that the fire hazard such as flame propagation and smoke release of these cables are controlled. However, one more fire hazard of these fire-resistant cables is nothing but the heat released from these cables during a fire. Heat release of these cables depends upon the fuel loading of the cables and the energy available in the materials of these Fire Resistant or Fire Survival (FS) cables. In this paper, the heat release of FS cables is measured for various construction of the FS cables.Keywords
Fire Resistant Cables, Glass-Mica Insulation, Heat Release, Silicone Insulation.References
- BS 6387 - Test method for resistance to fire of cables required to maintain circuit integrity under fire conditions
- IEC 60331 - Tests for electric cables under fire conditions - Circuit integrity
- BS 8491 - Method for assessment of fire integrity of large diameter power cables for use as components for smoke and heat control systems and certain other active fire safety systems
- IS 17505 - Specification for Thermosetting Insulated Fire Survival Cables for Fixed Installation having Low Emission of Smoke and Corrosive Gases when Affected by Fire for Working Voltages upto and including 1100 Vac and 1500 Vdc
- BS EN 50200 - Method of test for resistance to fire of unprotected small cables for use in emergency circuits.
- An Approach to Determine Health Index of Power Cable System
Abstract Views :68 |
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Authors
Affiliations
1 Central Power Research Institute, Bengaluru - 560080, Karnataka, IN
1 Central Power Research Institute, Bengaluru - 560080, Karnataka, IN
Source
Power Research, Vol 18, No 1 (2022), Pagination: 9-12Abstract
Power Cable System is a vital asset in Electrical Power System. Now a days power cables are used in transmission and distribution of electric power at MV, HV and EHV levels. Reliability and availability of power supply depends greatly on insulation condition of the power cable system. Therefore, power cable asset management is vital for taking decision on future course of action to minimize capital expenditure, maximize reliability and avoid forced outages. In this paper, how to deploy power cable asset management is discussed using Health Index based on diagnostic test data.Keywords
: Asset Management, Condition Assessment, Diagnostic Testing, Health IndexReferences
- IEEE Std 400-2012, IEEE Guide for Field Testing and Evaluation of the insulation of the Shielded Power Cable System.
- IEEE Std 400.2-2013, IEEE Guide for Field Testing of the Shielded Power Cable System Using Very Low Frequency (VLF) (less than 1 Hz).
- IEEE Std 400.3-2006, IEEE Guide for Partial Discharge Testing of the Shielded Power Cable System in a Field Environment.
- IEEE Std 400.4-2015, IEEE Guide for Field Testing of the Shielded Power Cable System Rated 5 kV and Above with Damped Alternating Current (DAC) Voltage.
- Puhan DK, et al. CPRI Experience in Diagnostic Testing and Condition Assessment of Medium Voltage Power Cable System. 14th Doble Power Forum; 2016
- Puhan DK, et al. On-Site Partial Discharge Diagnosisof Power Cables-Case Studies and Field Experiences. CABLETECH; 2017
- Rao NB, Puhan DK, Sharma R. Dielectric diagnosis of extruded cable insulation by very low frequency and spectroscopy
- techniques- A few case studies. Power Research- A Journal of CPRI. 2018; 14(2) https://doi.org/10.33686/pwj.v14i2.144708
- Puhan DK, et al. Field testing and condition assessment of MV power cable system by Very Low Frequency (VLF) AC Testing. Power Research Journal of CPRI. 2020; 16(2).
- https://doi.org/10.33686/pwj.v16i2.155908
- Pre Qualification Test on 220 KV Cable System – CPRI Experience
Abstract Views :74 |
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Authors
Affiliations
1 Central Power Research Institute, Bengaluru – 560080, Karnataka, IN
1 Central Power Research Institute, Bengaluru – 560080, Karnataka, IN
Source
Power Research, Vol 18, No 1 (2022), Pagination: 13-17Abstract
With the development of XLPE cables and associated accessories up to 500 kV voltage level, XLPE Cable Systems are becoming the main back bone of the Power Distribution and Transmission system. The basic requirement of power cable is that it shall withstand the electrical, thermal, mechanical and environmental stresses imposed on it during its expected life of 25 to 35 years. Generally the development of cable for EHV applications is achieved through increased stress design, which demands very stringent quality requirements during production of cables and development of accessories. Since different designs are available for cables and accessories, it is essential to carry out long duration test to establish their compatibility and reliability. IEC 62067 for extra High voltage Cable accessories have incorporated the pre-qualification tests to check the long term reliability of the cable system in service before installation. This paper highlights the details of Pre qualification test on 220 KV Cable system conducted at CPRI for the first time in India.Keywords
EHV XLPE Cable, Electrical Stresses, Mechanical Stresses, Pre Qualification Test, Thermal StressesReferences
- IEC 62067-2011 -Power cables with extruded insulation and their accessories for rated voltages above 150 kV (Um = 170 kV) up to 500 kV (Um = 550 kV) – Test methods and requirements.
- IEC 60840-2020 - Power cables with extruded insulation and their accessories for rated voltages above 30 kV (Um = 36 kV) up to 150 kV (Um = 170 kV) – Test methods and requirements.
- Rao BN. Power cables laboratory “contribution towards research and testing in the CPRI golden jubilee period. 2011.
- Jahromi AN. Load cycling test of high voltage cables and accessoires. IEEE Electrical Insulation Magazine. 2011; 27(5):14–28.
- Tracking, Erosion and Morphological Study of Heat Shrink Anti Tracking Tubes
Abstract Views :69 |
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Authors
Affiliations
1 Cable and Diagnostics Division, Central Power Research Institute, Bangalore, IN
1 Cable and Diagnostics Division, Central Power Research Institute, Bangalore, IN
Source
Power Research, Vol 18, No 1 (2022), Pagination: 9-23Abstract
Components of Medium Voltage (MV) cable network are very much vulnerable under operational stresses and ageing. Heat Shrinkable Anti-Tracking Tube (HSATT), an integral part of the Joints and terminations of the MV cable network system is used to cover and safeguard the power cable joints. In cable system joint and termination are the weakest but the critical part and fail easily under stress. The most threatening source of HSATT failure is electrical tracking. Electrical tracking develops when a conducting path across the HSATT formed under electric stress due to surface discharge. Arcs created from this surface discharge phenomenon burn the HSATT and create carbonized tracks in the long run. This paper reports the electrical tracking performance of three commercially available HSATT samples. Crosslinked polyethylene (XLPE) is the key ingredient for heat shrinkable materials. Electrical tracking using the inclined-plane tracking (IPT) method develops from surface discharge activity followed by erosion under wet and contaminated conditions. So, the material under IPT test faced electrical, environmental and thermal stresses. Among these three HSATT samples two samples failed to withstand these three dimensional stress factors. Dielectric breakdown strength and volume resistance tests were carried out to cross examine the IPT results and the results are identical. The morphology has been studied to understand the failure mechanism of HSATT samples. A morphological model is presented to scrutinize the IPT test failure mechanism and the rate of erosion propagation in the HSATT samples.Keywords
Dielectric Breakdown, Heat Shrinkable Anti-Tracking Tube, Inclined-Plane Tracking Strength, Morphology.References
- Hoffman JE. Insulation enhancement with heat-shrinkable components. IEEE Electrical Insulation Magazine. 1991; 7(2):33-8. https://doi.org/10.1109/57.75767
- Kumagai S, Yoshimura N. Tracking and erosion of HTV silicone rubber and suppression mechanism of ATH. IEEE Trans Dielectr Electr Insul. 2011; 8:203-11. https://doi. org/10.1109/94.919930
- Piah MAM, Darus A. Electrical tracking performance of LLDPE- Natural rubber blends by employing combination of leakage current level and rate of carbon track propagation. IEEE Trans Dielectr Electr Insul. 2005; 12(6):1259-65. https://doi.org/10.1109/TDEI.2005.1561806
- Wang X, He HQ, Tu DM, Lei C, Du QG. Dielectric properties and crystalline morphology of low density polyethylene blended with metallocene catalyzed polyethylene. IEEE Trans Dielectr Electr Insul. 2008; 15(2):319-26. https://doi. org/10.1109/TDEI.2008.4483448