What questions do job interviews in power plants usually ask?

That depends on what major you are applying for. There are several specialties in power plant, such as boiler, steam turbine, electricity and thermal engineering. The boiler major will ask some questions about boiler structure, boiler water pressure and temperature, boiler water composition, and how to transform steam and water into each other. The steam turbine major will ask about the structure of the steam turbine, the pipes in the machine room, the direction of steam and water, the working principle of auxiliary equipment, etc. Electrical majors will ask some questions about generator excitation, main transformer, standby transformer, substation and electrical test; Thermal engineering majors will ask some questions about daily maintenance, overhaul, operation, DCS configuration, steam-water flow of the whole plant and so on.