## 1 Introduction
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Figure 1: HV bushings, lightning arrestors, and DLLs in a certain HV substation. [PERSON] et al. conducted on-site dynamic tests and a numerical FE analysis on a 160 MVA 230/135 kV power transformer, evaluated the coefficients (K and R) defined by IEC 61463 and calculated the natural frequency and seismic response of the entire transformer under different seismic loads. [PERSON] et al. experimentally studied the seismic performance of 196, 230, and 550 kV porcelain transformer bushings and noted the difference between the good performance of HV bushings in the laboratory and the poor performance of outdoor bushings in service. [PERSON] et al. [11] conducted a study on four transformer bushing models through a shaking table experiment and an FE simulation and noted that HV bushings installed on transformer cover plates were more susceptible to seismic loads than those installed on a rigid foundation. This conclusion is consistent with the conjectures and research results of many other scholars. [PERSON] et al. [12] used a shaking table and a group of artificial seismic waves to experimentally study a certain model of a 1100 kV ultra-high voltage (UHV) gas-insulated switchgear porcelain bushing based and obtained the acceleration, displacement, and strain responses of key parts of the porcelain bushing. [PERSON] et al. [13] conducted a shaking table test on a 1100 kV UHV bushing and obtained the acceleration and stress responses at the most unfavorable position of the casing. [PERSON] et al. [14, 15] studied the seismic response of surge arresters by considering the influence of the interaction of 220, 500, 750, and 1000 kV ceramic surge arresters with steel supporting structures. [PERSON] et al. [16] proposed a simple and practical method for estimating the expected displacement of the interconnection points of substation equipment under earthquake action. [PERSON] et al. [17] experimentally studied the dynamic characteristics of flexible conductors and the interactions between conductors and interconnection equipment using the shaking table test. [PERSON] et al. [18] clarified the importance of dynamic interactions between high-voltage bushings, turrets, and power transformer tanks through numerical simulations. These studies are of great importance for the seismic analysis and optimal design of HV substation structures. However, the existing research has mostly focused separately on the dynamic characteristics or seismic responses of HV bushings, HV bushing-transformer systems, and other devices, which means that those studies do not consider the adverse impacts of coupling vibrations on HV bushings and lightning arresters in whole systems under seismic loadings. Therefore, even when HV bushings, arresters and other substation devices meet standards for design and manufacturing, their mechanical characteristics and fatigue properties may not tolerate actual complex stress states in engineering practice. However, due to the limits of laboratory test conditions and the structural complexity of the actual HV bushings, arresters, and DLTL-connection systems, the current shaking table test studies of the interactions between flexible conductors and interconnection substation equipment are based on some simple test models that are quite different from actual structures. To date, there have been very few studies on the specific characteristics and influence of the coupled vibration responses of HV bushings, lightning arresters, and DLTL (HVB-LA-DLTL) systems. To address the topics discussed above, this study takes a 1000 kV UHV substation in Central China as an engineering example and uses ANSYS software to build an FE model of the HVB-LA-DLTL system. The time-history responses of the system under different seismic intensities are analyzed based on two groups of actual seismic records and one set of artificial earthquake waves. The results for the HVB-LA-DLTL system are compared with those for the corresponding single bushing and arrester under seismic loads.