Transformers are considered as the heart of the power system, and the majority of the transformers are oil filled in the existing electrical system. In transformers, presently, mineral oil is-used as a cooling and insulating medium, which is having good dielectric strength, high flash point & fire point, and high DC resistivity with low loss factor properties. However, it is losing acceptance in the electrical industry due to non-biodegradable petroleum by-products which are causing harm to the environment. Therefore, present studies are concentrated on biodegradable and eco-friendly insulating oil, such as natural ester oil and vegetable oil. It is considered to be the alternative for traditional insulating oil with the investigation of its electrical, thermal, and physical properties. In addition to that, with the recent development of nanotechnology, the above studies are being made with a mixture of nanomaterial and the alternative insulating oil, called nano-fluid. It provides an effective way to enhance the performance characteristics of biodegradable insulating oil. In this paper, critical parameters such as ‘Breakdown Voltage (BDV),’ ‘Flashpoint’ and ‘DC resistivity’ of Rice bran oil-based Titanium Oxide $(\mathrm{T}\mathrm{i}\mathrm{O}_{2})$ semi-conductive nano-fluids are investigated for probable use as an alternative to traditional mineral oil in the transformer.