Quzhou, Zhejiang: Pilot County Achieves Full Coverage of "Four Capabilities" in Distributed Photovoltaic Systems

On October 11, staff from the State Grid Quzhou Power Supply Company completed the final phase of the "Four Capabilities" retrofit at the 10kV Huanyu Bearing Photovoltaic Power Station. With this milestone, all 24 distributed photovoltaic (PV) power stations across Changshan County, Zhejiang Province, are now equipped with "Four Capabilities", marking a significant step forward in Quzhou's new energy grid-connection management and regional regulation. The achievement provides solid support for building a safe, efficient, green, and low-carbon modern energy system.

Staff from the State Grid Quzhou Power Supply Company inspect rooftop PV equipment in the Changshan County Industrial Park

Photo by Dong Ruiheng

With the large-scale integration of distributed photovoltaic systems, the intermittent and fluctuating nature of their power generation has posed challenges to grid stability and the consumption of green electricity. This issue becomes particularly pronounced during periods of significant load fluctuation, such as holidays, when reverse power flow and localized consumption difficulties often occur. Early PV power stations were equipped with diverse types of devices and non-uniform communication protocols, most of which lacked remote control interfaces, leading to the formation of information "silos".  A key challenge in the retrofit process lies in ensuring stable data acquisition and reliable command execution without disrupting normal power supply to users, while also coordinating multiple stakeholders to establish unified technical standards.

In order to address these issues, the State Grid Quzhou Power Supply Company established a dedicated task force and adopted a comprehensive, multi-measure approach. In terms of communication, a hybrid network was built—centered on the optical fiber dispatch data network—to ensure full channel coverage and high reliability. For older stations with poor communication conditions, the team innovatively applied "dedicated line simulation channel" technology to overcome protocol barriers between equipment from different manufacturers, ensuring effective data transmission. To achieve "controllability and adjustability", intelligent switches were installed on grid-connection lines, and inverter performance was deeply optimized. This formed an integrated "point-to-area" regulation capability, ensuring precise power output adjustment and safe, reliable control execution.

During the retrofit, comprehensive testing and debugging were conducted on each station's data collection, communication, and remote control systems to ensure stable and reliable operation. The company also organized county-wide joint dispatch and control drills for PV clusters, simulating scenarios of low load and high PV output during holidays. By combining the New Energy Active Power Intelligent Decision-Making Center with technologies such as Automatic Generation Control (AGC) and group dispatch, the company achieved unified decision-making and rapid response across PV systems ranging from 110kV centralized plants to 380V distributed stations—fully validating the "Four Capabilities" and laying a foundation for safe and stable grid operations.

Looking ahead, the State Grid Quzhou Power Supply Company will continue to deepen the application of the "Four Capabilities", explore multi-energy coordination and smart energy services, and further enhance both new energy absorption capacity and grid security, contributing to the region's green and low-carbon development. (By Zhu Tao, Xu Xuan)