Photo: State Grid Taizhou Power Supply Company

 On August 15th, State Grid Taizhou Power Supply Company adopted its pioneering "power protection and prefabrication" method during the capacity expansion operation of the distribution transformer at Qiaoyangyang No. 2 Substation, successfully resolving the issue of reverse overload caused by renewable energy sources in the transformer area.

Notably, the prefabricated transformer installation took just 30 minutes, one-sixth of the time required for traditional installation methods. Furthermore, the number of on-site workers was reduced from 9 to 6, and the entire process was completed without disrupting the consumption and grid connection of photovoltaic power generation. With the significant increase in distributed photovoltaic systems connected to the grid, reverse overload issues on power lines have become more frequent.

In May this year, Taizhou Power Supply Company organized a joint research team of relevant professionals to develop a "Power Protection + Prefabrication" method specifically for low-voltage live-working operations on photovoltaic reverse overload lines. This method enables automatic and rapid switching of lines when low-voltage distribution cabinets are disconnected from the grid, allowing for the consumption of generated electricity. After the transfer of low-voltage loads, operators use prefabricated modules to dismantle the original transformer and install a new transformer through modular hoisting.

This transforms the traditionally complex installation process on distribution poles into a relatively simple and rapid modular assembly, significantly enhancing the safety of live-working operations while drastically reducing power outages. On August 15, the on-site operators transported various modules, which had been prefabricated and assembled in advance at a factory, to the Qiaoyangyang No. 2 Substation work site. Upon connecting the energy storage vehicle to the line and disconnecting the low-voltage distribution cabinet, the mobile energy storage vehicle was linked to photovoltaic power generation customers.

With the cooperation of cranes and spider lifts, the operators assembled prefabricated modules such as transformers, fuse holders, grounding flat irons, and lead wires. The entire capacity expansion operation was completed in just 2.5 hours. During this time, nearly 160 kW of reverse photovoltaic load from the transformer area was seamlessly connected to the energy storage vehicle for consumption without any disruption.