You can go to the postgraduate enrollment website of North China Electric Power University: 8080/zhaoshengxinwang/. Generally, it is courses such as circuit, analog electricity, digital electricity and power electronics technology. It depends on the direction you choose. After choosing the right direction, you can choose one of the following subjects to fill in your volunteers, and then take the exam at the second interview. Don't bother about the second interview now. Review the unified examination before registration. The second interview is easy.