1100kV变压器套管抗震性能

Seismic Performance of a 1 100kV Transformer Bushing

为评估某型号1 100 kV变压器陶瓷套管的抗震性能,对该型套管进行了有限元分析和振动台试验。有限元分析和振动台试验得到了套管的自振频率和振型以及套管在地震波激励下的加速度、应变和位移响应。有限元分析基本预测了套管的动力特性和地震响应。结果表明:该型特高压变压器瓷套管前3阶的模态频率都在地震动的主要频率影响范围内,套管的振型为弯曲变形,阻尼比仅为0.009 8;在单向幅值为0.5g(g为重力加速度)的地震激励下,套管没有出现结构性破坏;套管的加速度响应以第1和2阶模态振动响应为主;套管空气侧瓷套底部的变截面处的抗拉正应变达432με(ε为应变),根部抗拉正应变为120με;套管顶部和底部的位移响应分别达92mm和12 mm;套管法兰处的弯曲刚度发生了较大变化,法兰处的抗弯刚度仅为相邻瓷套抗弯刚度的1/7。

In order to evaluate seismic performance of a 1 100 kV transformer porcelain bushing,the finite element analysis（FEA） and shake table test on the 1 100 kV transformer porcelain bushing were carried out. Modal frequencies, modal shapes and acceleration, strain, displacement responses of the ultra-high voltage （UHV） bushing under matched earthquake motion excitation were acquired. FEA predicates dynamic properties and earthquake responses of the UHV porcelain bushing. Results indicate that the first 3 mode frequencies of the bushing are in the main frequency range earthquake motions, the modal shapes are bending deformations, and equivalent damping ratio is 0.009 8. Under un-axial earthquake excitation with PGA of 0.5g, the bushing survives in the test; the acceleration responses of bushings are mainly the 1 st and 2nd modal vibrations. Strain responses at the diameter change section, and at the bottom of airside insulator of the bushing induced by bending deformation reach 432 micro-strains （με） and 120 micro-strains （με）, respectively. Displacement responses at the top and bottom tips of the bushings arrive at 92 mm and 12 mm, respectively. The bending stiffness of the bushing flange will change rapidly, which is only 1/7 that of adjacent porcelain section.