Photo: State Grid Kuitun Power Supply Company

At 3:26 am on August 28, with the successful energization of the 220 kV No. 1 main transformer for power transmission at 220 kV Kuitun Substation, State Grid Kuitun Power Supply Company successfully completed the task of upgrading and replacing the No. 1 main transformer at 220 kV Kuitun Substation.

This is also the fourth 220 kV main transformer replacement work completed by the company this year.

The 220 kV Kuitun Substation is an important hub station in Kuitun area. Its No. 1 main transformer was put into operation in 2005. Kuitun Substation connects Dushanzi District in the south and Wusu City in the west. It has mutual power supply with the Seventh Division of the Corps. While meeting the power consumption needs of local loads, it undertakes the power supply tasks of Kuitun, Wusu, Dushanzi and other areas.

In recent years, the economy of Kuitun City and surrounding areas has been developing well, putting forward higher requirements for power demand and reliable supply. Preliminary diagnosis found that the No. 1 main transformer had insufficient short-circuit resistance capacity, increasing the risk of power grid operation. It is urgently necessary to replace the main transformer.

For this equipment upgrade and renovation, the 220 kV No. 1 main transformer body, the low-voltage side isolating switch of the main transformer, and the three-side conductors of the main transformer in this substation have been upgraded and renovated. After the upgrade and renovation, the capacity of the No. 1 main transformer has been increased from 150 MW to 180 MW, enhancing the short-circuit resistance capacity, strengthening the power grid structure of Kuitun Power Grid, and ensuring the safe and stable operation of the power grid during the peak summer period.

This renovation started on August 16 and ended on August 28. Multiple processes such as oil drainage of the old main transformer, removal and displacement of the main body, installation of the new main transformer in place, vacuum pumping and oil injection, and handover test were completed item by item. It involves a sixth-level power grid risk. The entire renovation process is a third-level operation risk. Among them, the process of replacing the main transformer is a second-level operation risk.