Zhejiang UHV equipment inspected before summer power peak

As summer electricity demand rises, ensuring stable power supply has become a key concern. On June 8, the EHV Branch of State Grid Zhejiang Electric Power completed comprehensive maintenance on key equipment at the 1,000-kV Liandu Substation, including the No 4 main transformer and T051/T052 circuit breakers.

This marks the end of the province's spring maintenance mission for ultra-high voltage (UHV) equipment, meaning Zhejiang's UHV grid is now ready for the summer peak, offering more reliable power to households and industries.

UHV grids are crucial for long-distance, high-capacity transmission, acting as the main artery of Zhejiang's power supply. This spring, the company carried out a systematic health checkup and upgrade on UHV geographic information system (GIS) equipment, which functions like the grid's central nervous system.

To ensure safer electricity for the public, the maintenance team proactively intervened during equipment manufacturing. In mid-April, a 10-expert team visited the manufacturer's site to carry out inspections, identifying six issues such as worn static contact fingers and damaged closing resistor chips.

During factory tests, technicians used multiple diagnostic methods, recorded partial discharge waveforms, and signed a 10-year warranty agreement with the manufacturer for the arc-extinguishing chambers.

On May 18, one week before maintenance began, all personnel arrived early to prepare. The team was split into eight groups, conducted four full-process drills and two rounds of skill assessments, formulated 28 risk prevention measures, and prepared 38 technical disclosure records and 15 risk control checklists.

At the maintenance site on May 28, workers wore head-mounted recorders to document internal inspections and used endoscopes to examine hidden components like shielding covers.

Thanks to these methods, they managed to discover and fix severe ablation on an internal equalizing wire inside a circuit breaker — a hidden hazard that could have affected normal operation.

To avoid collision risks during equipment alignment, the team independently designed five new tools, including a switch alignment lifting fixture, a flexible dust-proof shelter, a fixed tie-rod positioning device, and a dedicated transport cart, effectively reducing operational risks.

Throughout the process, the company followed standardized procedures, ensured precision in their work, and ensured thorough documentation, improving both maintenance quality and safety.

Moving forward, it will continue refining this management system to enhance the standardization, precision, and intelligence of UHV equipment management, ensuring a safe and stable power supply for Zhejiang.