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Ph.D. Thesis Colloquium

July 19 @ 2:30 PM - 5:00 PM IST

Colloquium Announcement

Candidate’s Name       :  BABY SINDHU A V

Degree Registered      :  Ph.D.

Date  & Time                :   19th July 2023 @ 2.30 PM

Venue                            :   Seminar Hall, High Voltage Lab and in the Teams Link

Title                               :  Development of Polymeric Nano/Micro Composite Insulation with

                                     Better Performance for Various High Voltage  Power Applications



The  demand for electrical  power is increasing  day by day  necessitating a higher voltage level for power transmission and the development of high speed rails , electric vehicles, more electric aircrafts and all electric ships demand for improvement in electric motor capacity in those vehicles. Also the use of cast resin type dry transformers in high moisture area and confined area is increasing since it is more reliable in extreme conditions and also they require less maintenance. All these applications demand for  better insulating materials which can address all the above issues cost effectively. In  recent years,  the use of  polymeric insulating material  in HV power apparatus is increasing. Hence this study focuses on the development of polymeric  composite insulating  material  for various electrical power applications.

Silicone rubber is a  preferred  material for use as weathershed material in outdoor polymeric insulators used in high voltage power transmission lines.   The tracking & erosion on the insulator surface due to the electrical discharges  and corona cutting  of the insulator surface  are the main issues related to outdoor polymeric insulators and these are  addressed in this study.   Tracking and erosion performance of silicone rubber filled with nano/micro fillers of different loadings is  analysed using Inclined Plane Test (IPT) as per IEC 60587.  A computational study on the behavior of the samples subjected to  tracking  is also done and the same is verified with the experimental results obtained in this work. Corona ageing studies are done by ageing the samples in a corona chamber for 25 hours. Hydrophobicity changes, crack width formation and erosion performance after corona ageing are evaluated. An effort is made to correlate the value of leakage current to the eroded mass and a reliable online condition monitoring tool is also developed as a part of the thesis work.

   Again, epoxy is extensively used in  many  electrical  power apparatus such as ground wall insulation of the high voltage rotating machines, as spacer material  in Gas Insulated Substations (GIS), as solid insulation in dry type transformers etc. Heat dissipation is an important area of concern when using  epoxy as ground wall insulation in rotating machines and as an insulation in  cast resin dry type transformer. The performance of epoxy filled with nano/ micron sized fillers are  investigated in this study in terms of their heat removal capacity and at the same time  retaining their dielectric properties. The improvement in thermal conductivity is correlated with the performance of various composites developed. The formation of track in the ground wall insulation and the failure of the machine is a major issue as far as rotating machines are considered. Hence the tracking time of various epoxy composites are observed and compared. The initiation of a faint track on the surface of the insulator is monitored with the help of a ratio of third harmonic component to the fundamental component. This ratio can be used as an efficient condition monitoring tool for rotating machines by measuring the leakage current online.

    In summary polymeric composite insulating  materials based on silicone rubber and epoxy with different fillers and loadings and having   better electrical and thermal performance than the conventional materials  are developed in this study.


                                                                                                   All are welcome


Meeting link


July 19
2:30 PM - 5:00 PM IST