Seismic interaction and improved design method of substation equipment with multiple electrical configurations

A substation is a complex coupled system composed of various electrical equipment. Compared with standalone equipment, there is a significant coupling effect in the seismic response of interconnected equipment. To address this issue,this study investigates the seismic interaction of substation equipment with multiple electrical configurations and proposes an improved seismic design method. First, the concept of the coupling coefficient is introduced, which is used to improve the Newmark-β method and response spectrum method for the seismic design of standalone equipment. Then, the finite element models of a substation system with multiple configurations are established, and the vibration characteristics and seismic responses of the interconnected equipment are investigated. Finally, the coupling coefficients are obtained by kernel density estimation of the response results under twenty seismic ground motions, and the effectiveness of the proposed method is verified through two numerical examples. The results show that the frequency coupling coefficients vary from 0.69 to 1.42,while the seismic action coupling coefficient has a wider range, changing from 1.04 to 3.91. The coupling effect amplifies the seismic response of higher-frequency equipment, and the amplification degree varies among different configurations for the same type of equipment.