In January 1935, during the Long March, the Central Committee of the Communist Party of China (CPC) convened a meeting in Zunyi, Southwest China’s Guizhou Province. At this meeting, by the light of a kerosene lamp, the CPC for the first time independently resolved issues crucial to the Chinese revolution.
Now, more than 90 years later, the core zone of the Zunyi Meeting site, covering 0.65 square kilometers, features a lamp, a piece of equipment and a stage control system that are all supported by a smart power grid.
“The site of the Zunyi Meeting is one of China’s famous Red culture landmarks, where more than 40 events are held every year that need a high-level power supply guarantee. It places extremely strict requirements on power supply, allowing no power interruptions, which means that users should not be aware of any impact of voltage fluctuations,” said an official of the Zunyi Honghuagang Power Supply Bureau of China Southern Power Grid Co., Ltd. (CSG) Guizhou branch.
In December 2024, the CSG Guizhou branch completed construction of a highly reliable demonstration zone covering the core area of the Zunyi Meeting site. In the demonstration zone, the average annual outage time per user does not exceed five minutes, with a power supply reliability rate reaching 99.999 percent. Since it went into operation, the demonstration zone has guaranteed power supply for 34 major events.
Dianhong is China’s first electricity IoT operation system independently developed by CSG. [Photo/sasac.gov.cn]
A plain, white smart switch cabinet standing outside the meeting site can transmit more than 10 pieces of real-time data to a production command center three kilometers away. At its core is Dianhong, China’s first electricity IoT operation system, independently developed by CSG. Via Dianhong, the cabinet can detect an overload that may cause a trip and send precise operation and maintenance instructions to frontline workers’ mobile phones, shifting problem-solving modes from post-hoc response to early warning.
Zunyi has staged the immersive show Great Turning Point, where its water curtain, lighting and mechanical installations are all controlled via automated programs and cannot tolerate even 0.1 seconds of interruption.
To ensure smooth performance, the local power supply bureau built a 10-kilovolt dual-circuit power supply system for the theater, with one circuit serving as the primary supply and the other as a backup. Together with an intelligent automatic transfer switch, the system can switch between power sources within seconds. An uninterruptible power supply is also installed to ensure performance equipment stays online even under extreme circumstances.
Workers of CSG Zunyi Power Supply Bureau ensure power supply at the theater. [Photo/sasac.gov.cn]
Strong winds and tree-related disruption easily cause trips on medium- and low-voltage lines. More than 100 sycamore trees flanking the Fenghuang South Road were prone to tripping lines when their branches swayed in strong winds. Since these trees are protected as part of the cityscape, construction could not damage their roots. With the road narrow and busy, daytime work was out of the question. To address these problems, workers chose to close the road at 10 pm for construction and restore the road surface at 5 am, and they worked on this schedule for more than 20 consecutive days. After the construction, all lines were put underground, making the power supply along the road solid as a rock.
In addition, four 10-kV lines in the demonstration zone have been optimized with regard to their load distribution so that each line can transmit power to the others via their ends. These distribution lines can automatically reroute power and transfer loads within seconds, even if the substation suffers a total loss of power, placing the demonstration zone among the first areas in Guizhou to achieve coordinated self-healing between the main grid and the distribution network.
From single-line power supply to dual power sources, from overhead lines to underground cables and from manual load transfer to intelligent self-healing, power supply for the Zunyi Meeting site has undergone a robust upgrade spanning 90 years. However, work on the demonstration zone is far from over. By the end of this year, the demonstration area will be expanded to 1.45 square kilometers, covering 16 transmission lines and 24,200 households.
(Executive editor: Zuo Shihan)
