Abstract : This article discusses the application of a three-level medium-voltage inverter in the submersible electric pump and pumping unit of the Qinghai Oilfield, explains the difficulties in applying the inverter in the Qinghai Oilfield, and demonstrates its application prospects. Keywords : Medium-voltage inverter, Three-level, Applications 1 Introduction The Qinghai Oilfield is located at the junction of Qinghai , Xinjiang, and Gansu, on the Qaidam Basin, one of China's four major basins, at an altitude of nearly 3000m, making it the highest-altitude oilfield in the world. The geological and climatic conditions here are extremely harsh. Above are the snow-capped Kunlun Mountains, and below are barren deserts and saline-alkali flats, frequently experiencing sandstorms and raging sandstorms. The requirements for using frequency converters in this environment are quite stringent: (1) They must be able to withstand the test of high altitude and oxygen deficiency. Generally, the altitude of frequency converters is below 1000m, but now it is 3000m. The frequency converter must be downgraded and used one level higher than the motor to ensure the reliable operation of its components. (2) The plateau climate has a large temperature difference between day and night, especially in winter, which can be 20-30℃, and condensation or frost may occur. (3) They must be able to withstand the erosion of wind and sand. Here, especially in spring and autumn, sandstorms often occur, with strong winds carrying yellow sand that can make it impossible to see anything for tens of meters. (4) Most of the oilfield is located in saline-alkali land, which is highly corrosive. The components inside the frequency converter must be able to withstand the effects of the saline-alkali climate to prevent rusting and poor contact leading to failure. [b][align=center]For details, please click: Application of medium-voltage three-level frequency converter in Qinghai oilfield[/align][/b]