Installation procedure for gas-insulated fully enclosed combined electrical equipment: Foundation and component unit inspection ---- Sequential assembly and installation according to the manufacturer's unit numbering and sequence ---- Sulfur hexafluoride gas charging ---- Adjustment and testing. Leveraging advanced digital protection and control technology, sensors, and plug-in technology, the plug-in design enables rapid installation without the need for on-site gas charging or decharging. Strict environmental and process control is required during installation to avoid introducing foreign matter such as metal particles. Field examples show that residues from production and assembly processes, or debris generated during bolt tightening, may move under the influence of equipment operation vibrations and airflow, leading to electric field distortion or even insulation breakdown. Therefore, during equipment supervision, on-site installation, and commissioning, it is essential to ensure environmental standards are met and process procedures are strictly followed. For special applications such as offshore wind power, GIS is subject to long-term vibration loads from wind, waves, and tides during hoisting and transportation. Vibration simulation calculations must be performed during the design phase, and corresponding measures must be taken during installation.
GIS equipment testing mainly includes factory testing, handover testing after on-site installation, and preventative testing during operation. For example, the first batch of 500kV GIS units for Units 1 and 2 of the Xudabao Nuclear Power Plant underwent rigorous factory acceptance testing after manufacturing. To improve power supply reliability, uninterrupted power supply testing technology has emerged. For instance, the three-phase common-box type GIS double-break disconnector developed by the State Grid Hubei Electric Power Research Institute can form grounding protection by operating the disconnector while the busbar is energized, thus enabling uninterrupted expansion and testing of GIS equipment. In terms of testing technology development, full-condition realistic testing platforms capable of simulating actual operating conditions have emerged. For example, the "UHV GIS Full-Condition Real-Type Testing Platform" developed by Pinggao Group and others can simulate typical energized operating conditions such as GIS under pressure and current flow, circuit breaker and disconnector switching of unloaded busbars, and is used to conduct realistic tests such as metal particle effects and opening/closing tests. The integration of testing and online monitoring technologies is becoming increasingly close. Partial discharge online monitoring devices can be used to capture signals of internal insulation defects in equipment. Case studies show that in important links such as GIS power transmission, monitoring changes in partial discharge monitoring data before and after circuit breaker operation helps to discover potential sudden insulation faults. Therefore, optimizing online monitoring and alarm strategies and combining them with regular testing is an important means to ensure the reliability of equipment operation.