Power Research

Aditya Prakash Mishra ¹, R. T. Arun Ram Prasath ², Sankar Narayan Mahato ¹, Nirmal Kumar Roy ³, P. Thomas ⁴

Affiliations
1 EE Department, National Institute of Technology, Durgapur, IN
2 Ph.D. Full-time Research Scholar, EE Department, National Institute of Technology, Durgapur, IN
3 High Voltage and Insulation Laboratory, EE Department, National Institute of Technology, Durgapur, IN
4 Dielectric Materials Division, Central Power Research Institute, Bangalore, IN

Abstract

In general, insulating oil serves as an insulation and cooling medium of power transformers and different High Voltage (HV) application. The properties of insulating oil like breakdown voltage (BDV), viscosity, flash point and fire point are enhanced by adding of different additives in an optimal way. In this work, a mathematical model has been developed by using Lagrange interpolation technique for predicting the critical properties values in different volume concentrations (in Vol %). The predicted critical properties are compared with the set of measured data. Based on this approach, accuracy of predicted value has been obtained in between the two available measured data in two known different volume concentrations. From the volume concentrations (0-0.01%), the error seems to be negligible. Hence, Lagrange interpolation technique is considered as a reliable technique for predicting the intermediate value for different concentrations of nano powder doped insulating oil used in different HV power apparatus.

Keywords

Insulating Oil, Critical Parameters, Interpolation Technique, Nanofluids.

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R. T. Arun Ram Prasath ¹, Navdeep Ranjan ¹, Sankar Narayan Mahato ¹, Nirmal Kumar Roy ², P. Thomas ³

Affiliations
1 EE Department, National Institute of Technology, Durgapur, IN
2 High Voltage and Insulation Laboratory, EE Department, National Institute of Technology, Durgapur, IN
3 Dielectric Materials Division, Central Power Research Institute, Bangalore, IN

Abstract

Transformer is one of the cost effective and critical component in high voltage (HV) electrical system network. The quality of mineral oil is the key parameter to determine the health of the transformer. Globally, electrical and physical parameters of mineral oil are considered as the most primitive critical parameters for monitoring the transformer throughout the year. In this paper, electrical parameters like AC breakdown voltage (BDV), volume resistivity and physical parameters like flash point and fire point of new and aged mineral oil are analyzed by dispersing TiO₂ nanoparticles in mineral oil under different vol.% concentration. It is found that, new mineral oil with TiO₂ nanoparticles shows enhanced BDV compared with base mineral oil. In addition to this, volume resistivity, flash point and fire point also shows improved results with TiO₂ nanoparticles.

Keywords

Mineral Oil, Electrical Parameters, Physical Parameters, Tio₂ Nanoparticles, Nanofluids.

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Nandini. E. Hudedmani ¹, P. Thomas ¹

Affiliations
1 Dielectric Materials Division, Central Power Research Institute, Bangalore-560080, IN

Abstract

The nanofluids are considered as next generation insulating fluids for the transformer application. In this work, synthetic ester, MIDEL 7131 based nanofluids were prepared under ultrasonication by employing nanoceramics such as Ba0.85Ca0.15Zr0.1Ti0.9O3 (BCZT), Calcium Ferrite (CaFeO3) and eggshell nanomaterials. These nanofluids were evaluated for parameters such as AC breakdown voltage, loss tangent and resistivity, and also for viscosity and total acidity. There is an improvement in A C breakdown voltage for all the nanofluids under the study. There is no variation in the viscosity and total acidity for the nanofluids upto 0.005 wt percent of nanoceramic in a base oil. These nanofluids exhibited improved critical parameters.

Keywords

Synthetic Ester, Nanofluids, Mineral Oil, Nanomaterials, Electric Strength.

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P. Thomas ¹

Affiliations
1 Dielectric Materials Division, Central Power Research Institute, Bengaluru – 560080, IN

Abstract

The Polychlorinated Biphenyls (PCBs) one of the Persistent Organic Pollutants (POPs) has been used as dielectric fluids in transformers and capacitors, as plasticizers and in hydraulic fluids. Though PCBs never produced in India, the usage of PCB oils began in 1960 in India and PCBs have been imported mainly for transformers and capacitors applications. The imported PCBs-containing electrical devices were mostly distributed in large enterprises and the rest were distributed in the electrical power sector. The transformers that were installed prior to 1985 was identified and analyzed using GC/ECD technique. Around 1617 transformers are found to containing PCBs and out of which, 1150 transformers are declared as pure PCBs filled Transformers. From the analysis carried out on the 467 transformers, 225 were containing >500 ppm of PCBs and the remaining 242 transformers containing < 500ppm of PCBs. The major sector that owns PCBs containing equipment is the power sector (71%) followed by the steel industries (18%). The total weight of the PCBs oils and PCB contaminated oil is around 10,000 tons, which is being updated.

Keywords

Polychlorinated Biphenyls, Transformer, Inventory, India

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M. Padmini ¹, P. Thomas ¹

Affiliations
1 Dielectric Materials Division, Central Power Research Institute, Bengaluru – 560080, IN

Abstract

Electrochemical energy storage devices are considered as the propitious candidates to meet the energy needs of the future generations. Supercapacitor is one among which has its own unique properties such as long cycle life, rate capability, high capacitance and low cost. Due to these advantages, they are also investigated for the future power applications. Since electrode material plays a vital role in the performance of supercapacitor, there has been an immense attention paid by researchers to explore new materials. Furthermore, many investigations are also carried out to fabricate capacitor devices in various configurations to improve the energy and power densities. In this paper, we give a brief outline of electrode materials for supercapacitor and recent advancements in the device fabrication.

Keywords

Energy Storage, Upercapacitor, Electrode Materials.

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P. Thomas ¹, S. Vynetheya ², Girish M. Joshi ³

Affiliations
1 Joint Director, Dielectric Materials Division, Central Power Research Institute, Bangalore - 560 012, IN
2 Sci.Officer, Materials Technology Division, Central Power Research Institute, Bangalore - 560 012, IN
3 Assoc.Professor, Materials Physics Division, School of Advanced Sciences, VIT University, Vellore - 632 014, IN

Abstract

Composites comprising Polycarbonate (PC) and CaCu₃Ti₄O₁₂ (CCTO) were fabricated via melt mixing followed by hot pressing by employing both micron (1-7μm) and Nano (75-100 nm) sized crystallites of CCTO. Both the micro and nano CCTO powders were self-synthesized using solid state and co-precipitation routes respectively. These were characterized using X-ray Diffraction (XRD), Thermo Gravimetric (TGA), Differential Scanning Calorimetry (DSC), Scanning Electron Microscopy (SEM),Impedance analyzer for their structural, morphology and dielectric properties. Nanocomposites inducted with nCCTO-50 wt% exhibited better thermal stability than that of pure PC and composite embedded with micron sized CCTO. However, there was no significant difference in the glass transition (T_g) temperature between the polymer and the composites. The Nano composites (PC+nCCTO-50 wt%) exhibited 2.5 times higher permittivity values as compared to that of composites having 50 vol% micron sized CCTO crystallites.

Keywords

Polycarbonate (PC); CaCu₃Ti₄O₁₂ (CCTO); Composite; Thermal, Dielectric Properties

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