Executive Summary : | The rapid industrial growth has caused a high demand of uninterrupted and reliable power supply. In order to cope up with the increasing demand of uninterrupted power supply, it is inevitable to search for a new and advanced insulation within high voltage equipment that can have the higher dielectric strength and improved thermal conductivity. Currently, mineral oil is used as insulating medium for most of the high voltage transformers. However, shortage of mineral oil in the coming year amplifies development of alternating liquid insulation for high voltage transformers. Besides, emission of harmful greenhouse gases (byproducts of fossil fuels) discourages mineral oil for further its uses in high voltage transformers. Considering the drawbacks of mineral oil, synthetic ester is emerging as an alternative potential insulation for high voltage transformers due to its higher fire point. Therefore, the dielectric characteristics of synthetic ester based insulation need to be investigated for determining its suitability in high voltage transformer. In case of high voltage transformer, its insulation is stressed due to various factors (electrical, mechanical, thermal, chemical) during its operation. These stresses deteriorate the insulation characteristics and accelerate its ageing. The degradation of insulation can cause premature failure of transformer which may result power interruption. Being very costly and being important component in power system network, the premature failure of high voltage transformer is not desirable. In order to avoid catastrophic failure of transformer, regular condition assessment of its insulation is necessary. For oil filled transformers, various techniques have already been developed which can provide reliable information about the condition of insulation. However, being relatively new, the condition monitoring technique of synthetic ester filled transformer has been under development stage and therefore yet to be standardized. For oil filled transformer, dielectric spectroscopy both in time and frequency domain is widely used for assessing its insulation condition. The condition assessment results of high voltage transformers by dielectric spectroscopy both in time and frequency domain show its effectiveness for real-life application. However, the effectiveness of dielectric spectroscopy for condition assessment of synthetic ester filled transformers needs to be investigated. Considering this, dielectric characteristics of synthetic insulation model will be investigated through dielectric spectroscopy both in time and frequency domain. Besides, various nano-particles will be mixed with the synthetic insulation model to investigate any improvement of its dielectric characteristics. Any improvement of breakdown characteristics of synthetic ester insulation model (both pure and nano-particles based) will also be investigated through conducting experiments. |