110kV干式空心并联电抗器振动台试验与易损性研究∗

Shaking Table Test and Seismic Fragility Analysis of 110 kV Dry Type Hollow Electrical Reactor

摘要:

电抗器是变电站的重要设备之一，上部线圈由底部陶瓷绝缘子支撑，整体尺寸大、重心高。由于结构形式的特殊性，其在地震作用下的动力响应较为复杂。本文对 110 kV 干式空心并联电抗器进行了振动台试验研究，通过白噪声测定了电抗器的自振频率和阻尼比；在 0.15g 和 0.5g 人工地震动输入下，测量了电抗器关键部位的应变、加速度和位移响应，分析了电抗器在地震作用下的动力响应规律，探讨了电抗器的可能破坏模式，进一步计算了电抗器的地震易损性曲线。研究结果表明：电抗器的动力特性近似于单自由度体系，一阶自振频率为 3.3 Hz，阻尼比为 3.9%；电抗器在地震作用下的变形主要发生在绝缘子以及绝缘子?线圈连接部位，上部线圈可认为是刚体；与绝缘子相比，绝缘子?线圈连接部位的刚度较小，变形更集中，是电抗器的薄弱部位；0.15g 人工地震动试验后，电抗器自振频率下降 3.6%，0.5g 人工地震动试验后，电抗器自振频率下降 6.3%；根据绝缘子实测应变，考虑地震作用与其他荷载产生的总应力，电抗器的安全系数为 2.14，仍然具有一定的安全储备；基于试验结果计算电抗器的地震易损性，抗震能力中值为 0.965g，对数标准差为 0.4。

Abstract:

Electrical reactor （ER） is one of the most important equipment in substation systems. The upper coil is supported by the bottom ceramic insulator， leading to a large overall size and a high center of gravity. The dynamic response of an ER under earthquake is complex due to its special structure. In this study， the seismic performance of a 110 kV dry type hollow ER was investigated using a shaking table test. The natural frequency and damping ratio of the ER were identified using white noise excitation. An artificial ground motion was used as the seismic excitation with amplitudes of 0.15g and 0.5g， respectively. The strain， acceleration， and displacement responses of the critical parts of ER were measured. The dynamic response pattern of ER was analyzed. The possible failure mode of ER was discussed. The fragility curve of ER was further calculated. The results show that ER performs like a single-degree-of-freedom system. The first-order natural frequency and damping ratio of ER are 3.3 Hz and 3.9%， respectively. The deformation of ER mainly occurs in insulators and insulator-coil connections， while the upper coil performs like a rigid body. Compared with insulators， the insulator-coil connections have smaller lateral stiffness and more concentrated deformation. Therefore， it is regarded as the weak point of ER. The frequency of ER decreases by 3.6% and 6.3% after the 0.15g and 0.5g seismic tests， respectively. Based on the measured strains of insulators， considering the total stress caused by seismic action and other loads， the ER exhibits some seismic capacity reserve with a safety factor of 2.14. The fragility curve of ER was calculated based on test results. The median capacity and the logarithmic standard deviation of ER are 0.965g and 0.40， respectively.