±800 kV特高压直流穿墙套管的地震易损性分析

Seismic vulnerability analysis of±800 kV ultra-high voltage direct current(UHVDC)wall bushing

为评估某±800 kV特高压穿墙套管的抗震性能,本文建立了穿墙套管-阀厅体系有限元模型,并对其进行了动力特性和地震响应分析,采用多样条的易损性分析方法,从强度和变形两方面拟合得到了穿墙套管不同损伤状态下的易损性曲线。结果表明:阀厅结构会影响套管的动力特性;穿墙套管根部截面的应力响应和绝缘芯子端部截面的相对位移响应较大,是抗震的薄弱位置;户外段套管根部的地震易损性最高,绝缘芯子端部地震易损性次之,户内段套管根部地震易损性较低。评估穿墙套管抗震性能时不能忽略阀厅的影响;应采取措施降低户外段套管根部的应力响应以提高其抗震性能;同时应评估由于穿墙套管内部结构与外部套筒间相对变形过大对电气功能的影响。

In order to evaluate the seismic performance of a ±800 kV UHVDC wall bushing, a finite element model of wall bushing-valve hall system was established. Dynamic characteristics and seismic responses analyses were carried out. And the seismic vulnerability curves of wall bushing with different levels of damage have been obtained based on strength and deformation aspects using the Multiple Stripes Analysis method. The results show that the valve hall structure will amplify the seismic responses of the wall bushing. Stress responses at the root section of the wall bushing and the relative displacement responses at the end section of the insulating body are the vulnerable points of the seismic responses. The root section of outer bushing has the highest seismic vulnerability, followed by the end section of insulating body, and the root section of inner bushing has the lowest seismic vulnerability. Therefore, the influence of valve hall structure cannot be neglected when evaluating the seismic performance of wall bushing. It is necessary to take measures to decrease the stress responses at the root section of the outer wall bushing so as to improve its aseismic performance. Meanwhile, it is also necessary to evaluate the influence on functionality caused by excessive relative deformation inside wall bushing.