Live-line work sets Northwest China record

State Grid Shaanxi Electric Power Co's Tongchuan branch has completed the first live-line replacement of composite suspension insulators on a 330-kilovolt double-circuit transmission line in Northwest China, marking a breakthrough in high-voltage maintenance.

A staff member from State Grid Shaanxi Electric Power Co conducts the live-line replacement. [Photo/WeChat account of State Grid Shaanxi Electric Power Co]

The operation took place on tower 13 of the Yuanjin line's phase B. The line shares towers with the 330-kV Liuyuan I line, forming a key transmission corridor serving Shaanxi.

As the lines age, deteriorating insulation and loose fittings can threaten grid stability. Conventional maintenance would require shutting down the transmission corridor, potentially disrupting power supplies to homes and industries. Instead, the team used live-line techniques to eliminate the defects without interrupting power transmission.

A staff member from State Grid Shaanxi Electric Power Co conducts the live-line replacement. [Photo/WeChat account of State Grid Shaanxi Electric Power Co]

The operation addressed challenges involving load transfer on bundled conductors and electric-field interactions between circuits. Workers used specialized insulated lifting tools and continuous safety monitoring to maintain safe working distances.

The team also deployed drones for on-site inspections and a motorized lifting device, the "Little Flyer", to access the high-voltage work area, replacing traditional climbs on insulated ladders. The approach improved work efficiency by more than 40 percent.

This successful operation strengthens the branch's capabilities in complex high-voltage maintenance and helps ensure a stable power supply across the region.