On October 26, the State Grid Shaoxing Power Supply Company completed the protection and measurement-control retrofit of the No.3 main transformer at the 500kV Cangyan Substation in Shaoxing, Zhejiang Province, effectively resolving challenges associated with limited maintenance of imported equipment and achieving autonomous controllability of the substation’s secondary equipment.
The Cangyan Substation is the only extra-high-voltage hub substation in the Xinchang area of Shaoxing. With the growth in years of operation, the protection devices of the No.3 main transformer at the substation have aged, and equipment defects have increased year by year. The original measurement-control device of the main transformer was an imported piece of equipment that had been in operation for over 17 years, facing problems including discontinuation of core components, weakened technical service support from the original manufacturer, difficult maintenance, and a high defect rate of key plugins. The localization upgrade of the aged equipment at the Cangyan Substation has improved the operational stability and autonomous controllability of the substation’s secondary equipment.
To minimize the impact of maintenance on customers’ production and daily life power usage, the Shaoxing Power Supply Company studied the load characteristics of the supply area in October, actively coordinated with the dispatching and control center of State Grid Zhejiang Electric Power Co., Ltd. to transfer loads, and locked in construction windows to ensure that both maintenance and power supply were maintained.
The retrofit involved the assembly and disassembly of 17 protection panel cabinets, required replacement of 15 kilometers of cables, verification of more than 4,000 terminal connections, and completion of nearly a hundred loop transmission tests and dozens of device commissioning works. The retrofit adopted a “new panel position, new panel cabinet” operation method. Before the power-outage retrofit, maintenance personnel completed preparatory works including cable laying for new panel cabinets, protection panel erection and wiring, and device commissioning. Compared with the method of directly replacing new panel cabinets at the original panel position during power outage, this approach reduced the main transformer power outage time by 3 days.
Meanwhile, the Shaoxing Power Supply Company adopted a “one outage, multiple uses” maintenance mode, synchronously completing multiple equipment maintenance and hidden danger rectification works, comprehensively improving the health level of substation equipment. The company continues to advance the localization upgrade of imported aged equipment, further strengthen independent implementation capabilities in core businesses, and continuously enhance the intrinsic safety level of the power grid.
Source:Bjx Power Grid