The successful load-test and energization of the three-terminal optical differential protection for the 110 kV Changshi 966 feeder from the 220 kV Changdian Substation marks the on-schedule, trouble-free grid connection of the 50 MW/100 MWh Fengxian energy-storage station of Xukuang Group after five straight days and nights of work.

The project was executed under tight deadlines and heavy workloads. Maintenance crews from the State Grid Xuzhou Power Supply Company worked continuously, seizing every available minute. At 00:00 on July 12, the Changshi 966 line was switched to an outage for maintenance. Secondary maintenance workers from the substation inspection center immediately implemented secondary safety measures for the maintenance bay; once the measures were in place and all parties were briefed, they supervised the contractor's subsequent operations.

Throughout the campaign, the company strictly fulfilled its "on-site attendance and responsibility" mandate, assigning senior engineers to daily supervisory shifts. Full compliance with safety measures and pre-control plans were verified, and dynamic risk assessments were conducted on site. Close coordination with local transmission and substation O&M units, the information & communication company, and other stakeholders ensured seamless integration of all workflow stages—optical-cable laying, protection commissioning, telecontrol point-to-point testing, setting calculation, CT testing and final acceptance—greatly enhancing both site safety and the accuracy of acceptance tests.

After five consecutive days and nights of intensive work, all pre-energization modifications at Changdian Substation were completed on time and to specification, just as the summer peak-load period began.

The Fengxian energy-storage project is expected to play a critical role in enhancing supply reliability within the load center, while its successful grid connection will provide superior frequency-regulation and peak-shaving services for the Xuzhou power grid, facilitating further renewable-energy development and accommodation in the region.