Vol. 337 No. 8 (2026)
DOI https://doi.org/10.18799/24131830/2026/8/5823
Operation of step-up transformers of submersible electric centrifugal pumping units in low temperature conditions
Relevance. Submersible electric centrifugal pumps are widely used in artificial lift oil production in Russia. Their geographic reach is extremely wide, from the far north to the Middle East. The surface equipment of these pumps is exposed to harsh climatic conditions. In winter, ambient temperatures can drop to –60°C. The most vulnerable component of the surface equipment of electric centrifugal pumps is the step-up transformer. Submersible pumps are often operated in intermittent mode due to the high gas-oil ratio. During pumping shutdowns, the gas content in the wellbore fluid decreases. In cold climates, the step-up transformer cools to low temperatures during the shutdown. This causes the oil in the transformer to thicken, disrupting oil circulation and impairing heat dissipation. After switching on, the oil around the transformer core heats up faster than the oil near the tank walls, causing localized overheating and thermal stress. Mechanical fastenings in the transformer structure weaken, and the insulating materials become increasingly brittle. Therefore, intermittent operation significantly reduces the transformer service life and leads to its rapid failure. Installing a high-voltage switch at the step-up transformer output allows the transformer to remain idle during operational pauses, avoiding thermal stress upon switching on. Aim. To study the temperature regime of the transformer during intermittent short-term operation; to develop a power supply system for a submersible electric motor that allows the transformer to remain idle during process pauses, which eliminates the impact of temperature stress on the step-up transformer at the moments of switching on during intermittent short-term operation of the well in low-temperature conditions. Methods. Methods for determining transformer temperature, thermal imaging control. Results. The authors have proposed a submersible electric motor power supply system that allows the transformer to remain idle during operational pauses. This eliminates the impact of thermal stress on the step-up transformer during short-term well operation in low-temperature conditions, reduces its wear, and increases its service life.
For citation: Shaidullin V.F., Shumikhin A.Yu., Khakimyanov M.I. Operation of step-up transformers of submersible electric centrifugal pumping units in low temperature conditions. Bulletin of the Tomsk Polytechnic University. Geo Assets Engineering, 2026, vol. 337, no. 8, pp. 102–111. http://doi.org/10.18799/24131830/2026/8/5823
Keywords:
electric submersible pump unit, step-up transformer, intermittent mode, temperature stress, power supply system
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