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Ph.D. Thesis Colloquium
July 19 @ 2:30 PM - 5:00 PM IST
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