In the northern part of Northeast China's Liaoning province, Li Yingfeng has dedicated over three decades to ensuring reliable electricity for thousands of households in Tieling.

As a senior technician at Tieling Power Supply Co, a local branch of State Grid Corporation of China, Li is responsible for the safe operation of 27 substations across the region.

Li leads a seven-member team in the substation maintenance unit. Under his leadership, all 27 substations have maintained 100 percent on-time inspections, accurate fault responses and timely defect repairs. Since he became team leader, the group has had 18 straight years of safe operations without a single accident.

"When I first started, the equipment was old and often broke down," Li said, recalling long days spent rushing between stations to fix problems.

"Sometimes we didn't even have time to eat. I remember one winter when we worked 36 hours straight to repair a station in freezing weather," he added.

Thanks to Li's experience and expertise, the team, with an average age of 35, has maintained a 6,570-day record of safe operations and completed the smart upgrades of 27 substations, ensuring the safe delivery of 6.651 billion kilowatt-hours of electricity annually to northern Liaoning.

In August last year, Li responded to a late-night emergency when a hydropower station had a control fault. Braving heavy rain and strong winds, he found and fixed the problem before morning.

"Emergency repairs like this are part of our job," he said. "Keeping the power grid safe is my responsibility."

Li established an innovation workshop that has since developed 28 technical solutions and secured 26 national patents in 2015. His handbook on common defects in relay protection systems has become a widely used reference across the industry.