Abstract: The main goal of electrical secondary design is to provide stable and reliable power supply for high-voltage switchgear, and provide necessary protection and control functions to ensure the stability and safety of the power system operation. Including the selection of current, voltage, protection, measurement and control equipment, as well as the layout and connection method of the circuit. In the design, factors such as on-site environment, working conditions, and maintenance requirements need to be considered, and relevant electrical safety regulations and standards should be followed.Through reasonable design and configuration, the reliability, safety, and efficiency of high-voltage switchgear can be ensured, thereby meeting the various needs of the power system.