Power Research

B. Nageshwar Rao ¹, R. Arunjothi ¹, A. R. Srinivasan ¹, P. Rajashekhar ¹, A. Sudhindra ¹

Affiliations
1 Central Power Research Institute, Bengaluru, IN

Abstract

This paper presents and discusses heat release measurement, smoke and toxicity data obtained on cables: power, communication, automobile, wires and other materials used for various applications in power plants, petroleum refineries, metro rail, automobile industries. Fire survival cables intended to maintain electrical integrity under flaming conditions and flame retardant low smoke cables have been evaluated and their performance discussed. Fire safety assessment methods of cables and materials are reviewed and heat release rate, smoke, toxicity data and flammability characteristics obtained on materials like polystyrene, cellulosic fibre materials, upholstery, FRP/GRP laminate and others are discussed. Cushioning materials like polyurethane foam (slab stack, rigid PU, Expandable Graphite foam), thermally densified polyester block have been evaluated for HRR, smoke properties and the results are discussed. The toxicity of these materials evaluated as per NES 713/NCD 1409 are summarised.

Keywords

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K. P. Meena ¹, R. Arunjothi ¹, Thirumurthy ¹, G. K. Raja ¹, B. Nageshwar Rao ¹

Affiliations
1 Diagnostic, Cables and Capacitors Division, Central Power Research Institute, Bangalore-560 080, IN

Abstract

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

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R. Arunjothi ¹, Thirumurthy ¹, P. V. Satheesh Kumar ¹, G. K. Raja ¹, K. P. Meena ¹

Affiliations
1 Central Power Research Institute (CPRI), Bengaluru – 560080, Karnataka, IN

Abstract

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, LSZH

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R. Arunjothi ¹, Thirumurthy ¹, K. P. Meena ¹

Affiliations
1 Central Power Research Institute, Bangalore - 560080, Karnataka, IN

Abstract

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.

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K. P. Meena ¹, Thirumurthy ¹, G. K. Raja ¹, R. Arunjothi ¹, P. V. Satheeshkumar ¹

Affiliations
1 Central Power Research Institute, Bengaluru – 560080, Karnataka, IN

Abstract

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 Stresses

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