Power Research

Moumita Naskar

Abstract

Polyaniline (PANI) and its derevatives are the upcoming materials in power application. They have several advantages due to their electronic and optic properties compared to the non-conducting polymers. The research interest on conducting polymers has been increased due to their reasonably good conductivity, good environmental stability, easy preparation techniques and redox properties compared to other organic compounds. Among the conductive polymers PANI and its derivatives invite more attention for their excellent adhesion and anticorrosive properties also. PANI can be used in rechargeable batteries, fuel cell, super capacitor, pH and gas sensor etc. This article aims to provide a short overview of the present status of research on synthesis, characterizations, development and applications of PANI and its derivatives.

Keywords

Power Application, Synthesis of Polyaniline, Conducting Polymer, Derivative, Blends and Composites,light Emitting Diode, Supercapacitor

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Ganga S. ¹, Moumita Naskar ¹, Prasenjit Biswas ¹

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

Abstract

Polymer nanocomposites have attracted wide interests in high voltage insulation due to their excellent electrical, thermal and mechanical properties. Among the new insulating materials extensively used as high-voltage outdoor insulation, silicone rubber (SIR) has received the most attention. Indeed, SIRs are gaining popularity as an effective counter-measure to handle the high voltage insulation problems. In recent times nano sized fillers (Nano fillers) have sought great deal of research scholars’ attention and has brought revolution in the polymer industry due to its better interaction with polymer. A relatively less quantity of nanofillers in comparison to micro filler is reported to achieve the required properties in SIR. In this review, the effectiveness of the most common nanofillers of SIR for dielectric applications along with various dispersion methods is presented. But numerous experimental investigations on nanocomposites have indicated a significant decrease in electrical, thermal, mechanical and surface properties, due to the agglomeration of nanofillers. Agglomeration can be reduced by using modified nanofillers & optimum quantity of nanofillers, high shear mixing, or by efficient filler dispersion methods but it is almost impossible to entirely eliminate this effect with the presently available technologies.

Keywords

Silicone rubber, Nanocomposites, Outdoor insulation, Filler dispersion methods

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Moumita Naskar ¹, P. N. Ashitha ¹, K. G. Rakesh ¹

Affiliations
1 Insulation Division, Central Power Research Institute, Bangalore – 560080, Karnataka, IN

Abstract

Underground Polyvinylchloride (PVC) sheath power cables are exposed to the atmospheric condition during installation. Depending on the atmospheric conditions the cable sheath is facing extreme environmental stresses such as ambient temperature (high and low), direct sunlight (UV) radiation, rain or water accumulation etc. The life of PVC cables is reduced by being exposed to harsh environmental conditions and can subsequently damage the unprotected cables. This work is aimed to the study of the effects of UV radiation and low temperature on PVC cable outer sheaths. Three commercially available PVC cable were chosen for the study. UV exposed PVC insulations become brittle after UV exposure and in low temperature. UV exposure eventually results in material degradation, diminishing the performance characteristics of the material. Thermogravimetric Analysis (TGA) was used to characterize the thermal behavior of PVC cable insulation materials before and after UV ageing. In addition, Fourier-transform infrared spectroscopy (FTIR) was used to reveal the chemical processes that caused the UV degradation of the sample. A good agreement between results of the methods was found. Exposure to low temperature resulted in a reduction in stiffness of the polymeric structure caused embrittlement which transformed the PVC structure from a flexible material capable of undergoing large strain elastic behaviour to a stiffer material with higher yield behaviour.

Keywords

Cold Elongation, UV Radiation, FTIR, PVC, TGA

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Moumita Naskar ¹, H. M. Dharmendra ¹, K. P. Meena ¹

Affiliations
1 Cable and Diagnostics Division, Central Power Research Institute, Bangalore – 560080, Karnataka, IN

Abstract

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 Cell

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Moumita Naskar ¹, K. P. Meena ¹

Affiliations
1 Cable and Diagnostics Division, Central Power Research Institute, Bangalore, IN

Abstract

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.

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