Sichuan Nanchong: Successful Commissioning of No.1 Main Transformer at 220 kV Dafang Substation

"At 3:37 am on May 30th, at the 220 kV Dafang Substation located in Jialing District, Nanchong City, Sichuan Province, accompanied by a stable 'humming' sound, the on-site operation and maintenance personnel of State Grid Nanchong Power Supply Company verified that the equipment was running normally. The No.1 main transformer was successfully energized, marking a phased success in the capacity expansion and reconstruction project of the 220 kV Dafang Substation in Nanchong."

It is reported that the 220 kV Dafang Substation, which was completed and put into operation in 2003, is an important hub substation in the southwest area of Nanchong. It mainly supplies power to the Jialing urban area and important users in this area. The capacity of the existing main transformers can no longer meet the development needs of the local power load, and the equipment in the substation has been in operation for a long time. Problems such as equipment aging have gradually emerged.

The capacity expansion and reconstruction project of the 220 kV Dafang Substation is the first time that State Grid Nanchong Power Supply Company has carried out infrastructure projects and major repair and technical transformation projects simultaneously in an operating substation. It is also the Company's No.1 construction project this year and officially started in February. The project is implemented in two phases. It is planned to replace the existing two main transformers, the 220 kV busbar, the 110 kV busbar and supporting equipment and facilities, etc. In combination with the power outage arrangement of the project, five major repair and technical transformation projects such as the transformation of the 220 kV circuit breaker and the major overhaul of the isolating switch will be implemented.

During the implementation of the project, the construction environment in the Dafang Substation was complex, with many multi-point cross operations. At the same time, the number of construction personnel reached more than one hundred at most, making the safety risk control difficult. Before entering the power outage construction stage, State Grid Nanchong Power Supply Company organized professional backbones from dispatching, operation and inspection, construction, etc. to form a party member technical breakthrough group to jointly conduct on-site surveys and formulate the optimal construction plan. The company also established two party member assault teams for power grid construction and substation operation and inspection at the project site, established a list-based management mechanism, divided the "combat" areas according to positions and capabilities, ensured that team members were distributed at key points, strengthened safety supervision, and organized specific implementation according to the progress to promote the construction accurately and efficiently on a daily basis.

On the day of commissioning, on-site professionals carried out operations item by item according to the commissioning plan to make full preparations for the commissioning. At 16:38 on May 29th, the on-site dispatcher issued instructions, and the commissioning work officially began. After five impulse closing tests of the No.1 main transformer, all primary and secondary equipment in the station met the operating requirements, and all indicators were operating normally. The No.1 main transformer was successfully commissioned.

As of now, the renovation of the No.1 main transformer, the 220 kV busbar, the 110 kV busbar and supporting equipment and facilities in the first phase has been completed. The replacement of the No.2 main transformer in the second phase will be carried out from September to November. After the entire project is put into operation, the transformer capacity of the Dafang Substation will double,

further improving the power supply capacity of the area, strengthening the power grid framework of Nanchong, and providing sufficient power guarantee for peak shaving in summer (winter). (Li Junzhi, Chen Luyao)