Development of a new type of 110kV inverted environmentally friendly current transformer and analysis of measurement accuracy test

SF₆ is widely used in the main insulation of current transformers at 66 kV and above due to its superior insulation performance. However, in the context of global climate change, SF₆ will be more strictly restricted. Therefore, developing new environmentally friendly current transformers suitable for high voltage levels is crucial for the green development of China's power grid. Based on the traditional SF₆ inverted current transformer structure, this article adopts a colorless, odorless, non-toxic, and highly degradable clean air Blue as an environmentally friendly insulation material, and designs and develops a prototype of a 110 kV inverted current transformer. This mainly includes two aspects. Firstly, a simulation model of a 110 kV inverted current transformer was constructed, and the maximum internal electric field strength values under different load conditions were compared and analyzed. The study found that as the load current increased, the electric field strengthened. At a 120% load rate, the electric field strength value was 13.3 kV/mm; The second is to compare the measurement accuracy of the environmentally friendly current transformer, traditional inverted transformer, and SF₆ current transformer designed in this article under different load conditions. Through experiments, it is found that the current transformer designed in this article has a maximum difference of 33.33% and 17.65% compared to the traditional inverted transformer and SF₆ current transformer, and a maximum increase of 23.87% and 8.16% in angle difference, respectively, The experimental results show that the proposed design scheme meets the measurement accuracy of 0.1S level.