Power-line workers use drones to inspect lines in the hilly terrain around Hangzhou. [Photo provided to chinadaily.com.cn]

In early September, State Grid Zhejiang Electric Power Company emphasized supply reliability as the core benchmark of service quality and network resilience in preparation for the winter peak.

By upgrading the distribution network and accelerating digital and intelligent transformation, State Grid Zhejiang is building a highly resilient, self-healing smart grid that supports economic growth and improves quality of life.

On the network architecture side, State Grid Zhejiang is deepening feeder automation and one-click load transfer functions to enhance the grid's fault-handling and power-rerouting capacity. A joint project in Fuyang district and Tonglu county illustrates this approach by using instantaneous time-differential protection.

Integrating both voltage- and current-based protection mechanisms, the system connects the 10 kV Nan'an line from the 110 kV Wanshi Substation and the 10 kV Bao'an line from the 110 kV Fenshui Substation. Non-fault sections can be re-energized within minutes, significantly improving regional reliability and customer experience.

This autumn's operation and maintenance campaign incorporates drone inspections, intelligent robotic patrollers, infrared thermography, and partial-discharge detection to build an "air-space-ground" integrated inspection system. These tools enable end-to-end monitoring of key lines and substations. In mountainous and hilly areas where manual patrols are challenging, drones significantly improve both inspection efficiency and accuracy, enabling early detection and resolution of equipment defects.

State Grid Zhejiang has also established a "zero planned outage" demonstration zone in Hangzhou, where it promotes live-line working, mobile generator-grid integration, and other technologies to minimize the impact of scheduled maintenance. On Xinsha Island in Fuyang, the demonstration zone is tightly linked to low-voltage reliability governance through data.

By installing flexible low-voltage interconnection devices and IoT-enabled equipment, State Grid Zhejiang has created a transparent low-voltage pilot zone that accelerates fault recovery and improves supply quality — effectively bridging the final mile of customer service.