Seismic Performance Improvement Of +/- 800 Kv Uhv Dc Wall Busing Using Friction Ring Spring Dampers

Wall bushings that connect converter valves within hall buildings and other electric facilities in a direct current (DC) field are indispensable in substations but vulnerable to earthquakes. A finite element model was developed to evaluate the seismic performance of a real ultra-high-voltage (UHV) DC wall bushing. The numerical results show that the maximum stress of the wall bushing during seismic activity does not satisfy the strength safety factor provisions within Chinese regulations. To improve the seismic performance of the wall bushing, an energy dissipation device composed of eight friction ring spring dampers (FRSDs) was proposed to be installed between the connection plate on which the bushing is mounted and a steel wall frame. In addition, optimum parameters of the FRSDs were researched and determined, then the seismic responses of the wall bushing with and without the FRSDs were compared to evaluate the energy dissipation effects. Full-scale shaking table tests were conducted on a wall bushing with the designed energy dissipation device. The validity of the numerical simulations and effectiveness of the proposed energy dissipation device of the wall bushing were verified by the experimental results in terms of seismic response mitigation.