荆门特高压变电站扩建工程新增3台1 000 kV断路器，采用气体绝缘半封闭式组合电器(hybrid gas insulated switchgear, HGIS)，1 000 kV主接线由双断路器过渡接线完善为1个半断路器接线。结合该扩建工程的建设特点，分析了1 000 kV HGIS的“2+1”和“3+0”布置方式，研究了“3+0”方式面临的前期与本期HGIS基础不均匀沉降问题，计算了前、后2期基础的不均匀沉降量，提出了增加防沉降的伸缩波纹管补偿单元的方法以保障设备的安全运行。

Three 1 000 kV circuit breakers are added to the expansion project of Jingmen UHV substation. Hybrid gas insulated switchgear (HGIS) is applied that the arrangement of 1 000 kV main wiring was changed from double breaker transition connection to 3/2 circuit breaker connection. With the construction characteristics of Jingmen substation expansion project concerned, “2+1” and “3+0” layout mode of 1 000kV HGIS are analyzed. The uneven settlement problem of HGIS foundation under the “3+0” mode is studied. Then, the uneven settlements in early and late stage are both calculated. Finally, it is suggest that the compensation units of anti-sedimentation telescopic corrugated pipe should be added in order to ensure the safe operation of the equipment.