Injecting 4 million kWh of reactive power, Shanghai's power grid implements the nation's first reactive power demand response.

The first-ever reactive power demand response in China was successfully implemented in Shanghai's Lingang New Area, marking another significant step for Shanghai in optimizing its power system and improving power quality.

According to Shanghai's power authorities, as reported by The Paper on January 3rd, this response aims to address power quality issues faced by megacities, such as high rates of underground cabling, low user load during holidays, and the widespread use of power electronic devices in the grid.

On the evening of December 30, 2024, staff at a company located on Feizhou Road in Lingang New Area entered the distribution room and closed the connecting switch of a high-voltage reactor. Data showed that after the reactor was put into operation, the voltage instantly dropped and recovered by nearly 300 volts. "The reactor in the factory has basically not been used since it was purchased. This reactive power demand response is a good opportunity to test if the equipment is still functional," said the staff member. "We tested the equipment, received subsidies, and improved power quality – it's a win-win situation!"

A similar scene unfolded at two other enterprises. Under the unified invitation of State Grid Shanghai Municipal Electric Power Company, these companies activated user-side reactors within a specified time period, with a total capacity of 42 MVAr (Note: MVAr is a unit representing reactive power). During this New Year's Eve reactive power demand response, the three companies injected over 4 million kWh of reactive power into the grid by operating reactive power compensation equipment, significantly reducing and restoring system voltage during off-peak hours and effectively improving power quality.

Active power is the electrical energy converted into other forms of energy, such as thermal, light, or mechanical energy, while reactive power does not truly consume electrical energy but reflects the conversion between electric and magnetic fields within a circuit. Reactive power is the electric power required by electrical equipment to establish and maintain magnetic fields, and its unreasonable distribution can lead to voltage fluctuations in the power grid. Unlike traditional demand response, which balances active power by adjusting user-side electricity consumption loads, this reactive power demand response fully utilizes idle user-side reactive power compensation equipment for local compensation, thereby effectively stabilizing user voltage. This innovative practice means superior power quality and more reliable power supply for advanced manufacturing clusters such as artificial intelligence in Lingang New Area.

Cao Weibin, Director of the Lingang Energy Service Center of State Grid Shanghai Pudong Power Supply Company, explained: "Lingang New Area is located in the far eastern section of the Shanghai power grid, and electricity is transmitted through long-distance cables, making it prone to overvoltage issues due to insufficient reactive power support."

Currently, most high-voltage electricity consumers in the city are equipped with reactive power compensation devices. However, since the use of such equipment increases electricity costs, many user-side reactive power compensation devices remain idle for extended periods. To fully leverage the supporting capacity of user-side reactive power compensation equipment, State Grid Shanghai Electric Power has established a cost calculation model for calling user-side reactive devices and has pioneered a reactive power demand response pricing incentive mechanism in China. This mechanism uses price leverage to guide users to dynamically respond to the grid's reactive power needs, effectively activating large-scale existing resources on the user side.

During this year's Spring Festival, State Grid Shanghai Electric Power will also carry out actual call operations for all users, accurately issuing reactive power resource regulation demands based on grid operation needs. At the same time, it will continue to improve response work specifications and user compensation mechanisms, explore multi-time period and multi-regional scenario applications, and promote local economic development.