特高压交流同塔双回输电塔地震模拟振动台试验

为了分析地震作用下导、地线质量对特高压输电塔动力特性及其地震反应的影响,进行了特高压输电塔模型的地震模拟振动台试验。以某特高压输变电工程为背景,依据振动台试验相似理论,严格模拟了1 000kV特高压交流同塔双回输电塔,进行了不锈钢塔架模型的设计与制作。同时,针对地线及8分裂导线进行了相应的简化,制作了8个等效集中质量块悬挂在绝缘子下端用以模拟导地线质量。选取4种不同类型的地震动输入,针对单塔及单塔悬挂集中质量进行了8度罕遇烈度下的动力响应测试。试验发现,输电塔地震反应受所选地震激励类型影响较大;悬挂集中质量块后该型输电塔顺线路方向自振频率降低了5.7%,横线路方向自振频率降低了3.9%;单塔悬挂集中质量块后地震反应有所降低。导、地线质量的存在降低了输电塔的地震响应。

Shake Table Test on UHV AC Double Circuit Transmission Tower

In order to analyze the dynamic influence of the mass of conductor and ground wire on the transmission tower structure under earthquake,we experimentally investigated 1 000 kV UHV AC double circuit transmission tower in the presence and absence of conductor mass by shake table test.Taking an ultra high voltage transmission project as the prototype,we designed and fabricated a stainless steel tower model by the similarity theory for the scaled model of shake table test.The bundled conductors and ground wires was considered and simplified as eight lumped mass.Seismic responses of the tower model under seismic intensity of 8 were tested under four types of input ground motions.Experimental results show that the input ground motion has a remarkable influence on the seismic responses of transmission towers.The first natural frequency of the tower with lumped mass reduces by 5.7% and 3.9% over those of pure tower in the along-line direction and cross-line direction,respectively.The existence of the lumped mass effectively reduces the seismic response of transmission tower.