Prasenjit Basak

The growing demand for sustainable transformer insulation drives the development of environmentally friendly alternatives to conventional mineral oil. Although nanoparticle-enhanced ester-based insulating liquids exhibit improved dielectric performance, the influence of zinc oxide nanoparticle (ZnO NPs) morphology on the mineral oil–synthetic ester oil blend remains insufficiently understood. This work investigates a hybrid insulating nanofluid comprising mineral oil, synthetic ester oil, and hydrothermally synthesized ZnO NPs with nanoflower, nanorod, and nanosphere morphologies. Different mineral oil–synthetic ester oil blending ratios were evaluated, and 40% mineral oil–60% synthetic ester oil exhibits the highest alternating-current breakdown voltage (BDV) of 73.9 kV. The synthesized nanostructures were dispersed at different concentrations, and their dielectric characteristics were systematically evaluated. Among the investigated samples, the nanoflower-based nanofluid exhibits the highest BDV of 94.8 kV at 0.001 g/L, followed by the nanorod (87.9 kV) and nanosphere (78.7 kV). A comparative analysis of breakdown voltage, capacitance, and dielectric dissipation factor demonstrates the superior dielectric performance of the nanoflower morphology, which is attributed to its enhanced charge-trapping capability and electron-scavenging behavior that effectively suppress streamer propagation. These findings demonstrate the potential of nanoflower-based hybrid insulating nanofluids for next-generation power transformer insulation.

Sensor-based moisture monitoring in transformer oil is needed for preserving transformer health and preventing failures. This work reports the development and response of a humidity sensor fabricated using Indian anthracite coal-derived graphene oxide (AC-GO) as the sensing material, a novel approach for moisture monitoring in transformer oil. AC-GO is synthesized using a one-pot technique. The screen-printed electrode (AgCl) is used to offer a highly conductive platform on a glass substrate for the fabrication of a sensor. The behavior of the sensor represents both capacitive and impedance response with respect to a change in relative humidity (% RH), allowing effective moisture detection. By using graphene oxide derived from anthracite coal, the sensor provides a high surface area and excellent electronic properties, which together contribute sensor’s sensitivity. The sensor is tested in a transformer oil environment for moisture sensing across a wide range of frequencies and temperatures, which consistently delivers robust performance and reliability. The sensor shows excellent repeatability and long-term stability. Experimental results show that noticeable change in both capacitance and impedance as % RH levels and temperature changes, offering the sensor’s strong ability to monitor moisture accurately. These results confirm the sensor’s performance for industrial applications, especially for oil-filled transformers. The sensor’s response under varying % RH (5% –90% RH) and different transformer oil temperatures (20 °C–110 °C) at different frequencies is thoroughly evaluated. It highlights its potential for deployment in real-world applications, particularly for transformer condition monitoring.

Graphene oxide (GO)‐based humidity sensors are appealing because of their interesting physicochemical properties. This research focuses on developing a novel GO‐based relative humidity (%RH) sensor for detecting moisture in transformer oil. GO is derived from the modified Hummers method using graphite as a precursor. The sensor fabrication includes depositing the GO layer on a substrate by drop‐casting. The effects of vital parameters on sensor performance at different frequencies (100 Hz–100 kHz) for various %RH (10–90 %) are studied. The short‐term stability of the capacitive response of the proposed sensor, showing a maximum deviation of 6.7 %, was found. An experimental setup simulated the environment of an oil‐filled transformer to test the developed sensor inside the laboratory which can measure the moisture in transformer oil at different temperatures to prevent liquid insulation failure, ensuring longer life.

1. An independent network that connects critical and non-critical loads, integrating renewable and non-conventional energy sources (RNCES), is widely termed a microgrid (MG). It offers benefits by ...

In spite of the growing research in dielectric behavior of vegetable oils based dielectric nanofluids for transformers, there is no research available on the effect of these nanofluids on the constructional design parameters of transformers. This paper focuses on studying the dielectric behavior of graphene oxide nanoparticles dispersed green renewable dielectric fluid and its effects on the transformer size. The analysis of the design parameters has been done using a computational approach. The results show that the nanofluid immersed transformer core dimensions can be decreased by 38% with respect to the mineral oil immersed transformer.