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Power transformers are still equipment of primary importance within power grids. The recent paradigm changes registered in the field of energy require the interconnection of electrical grids of much larger areas, even up to the level of an entire continent. In this context, knowing the state of the electrical equipment and that of the power transformers is an essential aspect to ensure safe operation conditions. The present work is related to the vulnerability of the oil–paper insulation systems of power transformers to different aging factors and their quick degradation under certain conditions. In this regard, the study proposed in this paper considers the measurement of DC resistivity on mineral oil samples contaminated with small amounts of accelerated aging oil under the action of high-strength electric field and partial discharges. In the absence of standardized procedures for accelerated electrical aging of mineral oil, an original method presented and discussed in previous articles is used. The obtained results clearly indicate that under the action of electrical stress, the mineral oil resistivity decreases significantly, showing that the oil’s electric properties worsen.

During the operation of electric power transformers,their insulation often made from paper and mineral oil is subjected to thermal, mechanical, and electrical stresses. Therefore, the lifetime of power transformers can be assimilated with their insulation system lifetime. The aim of this paper is to explore and present main degradation aspects for mineral oil, subjected to the action of high electrical field and partial discharge and exposure to thermal stress exclusively, analyzing and pointing out changes in the dielectric properties. Thus, the obtained results indicate that both the thermal and, especially, the electrical stresses produce important variations of the values of the real and imaginary part of the complex relative permittivity, the electrical conductivity, and the loss factor which indicates a severe oil degradation.

In recent years robots have begun to become an active presence in everyday life in various forms. Helpful robots that offer help and support to people with special needs or social robots that are able to interact with customers in stores. The presented paper presents a method for design and implement a 6DOF robotic arm over the IoT concept. The core of this project is a Raspberry Pi board and the I2C protocol.