China’s Grid Transformation Accelerates with Smart Secondary Systems
As China races toward its dual carbon goals—peaking emissions by 2030 and achieving carbon neutrality by 2060—the nation’s power infrastructure is undergoing a profound metamorphosis. At the heart of this transformation lies not just the generation of clean energy, but the intelligent orchestration of how that energy flows through the grid. Nowhere is this more critical than in the distribution network, the final link connecting power sources to homes, factories, and electric vehicles. A new wave of innovation is reshaping the secondary systems that manage this last-mile infrastructure, turning passive wires into dynamic, self-healing, and data-rich arteries of the future energy ecosystem.
Recent research published in Electric Power Construction by a team from State Grid Economic and Technological Research Institute Co., Ltd. and State Grid Corporation of China outlines a bold architectural vision for the next generation of distribution network secondary systems. Led by DONG Chaowu, LOU Qihe, WANG Dengzheng, XIAO Zhihong, HAN Liu, and XIN Peizhe, the study confronts the mounting pressures on China’s grid: the explosive growth of distributed solar, the rapid adoption of electric vehicles, and the rise of behind-the-meter storage. These new energy assets are no longer just endpoints—they are active participants injecting power, drawing load, and demanding real-time coordination. The legacy grid, designed for one-way power flow from centralized plants to passive consumers, is straining under this new reality.
“The traditional model is breaking down,” said one industry insider familiar with State Grid’s modernization efforts. “You can’t manage millions of rooftop solar panels and EV chargers with 20th-century control logic. The distribution network needs eyes, a brain, and reflexes.”
That’s precisely what the proposed “control the middle, open both ends” strategy aims to deliver. The framework reimagines the entire data lifecycle—from acquisition at the edge to transmission, storage, and application—through a lens of modularity, interoperability, and intelligence. It’s a blueprint not just for reliability, but for enabling market participation, grid resilience, and seamless integration of decentralized resources.
At the edge, the challenge is visibility. Today, coverage of intelligent monitoring terminals in medium-voltage networks remains patchy—less than 50% for switchgear and under 30% for pole-mounted switches. On the low-voltage side, while smart meters are nearly ubiquitous, their 15-minute data polling intervals are too coarse for real-time control. The new architecture calls for a tiered deployment: “three-remote” (telemetry, telecontrol, and remote signaling) terminals in high-priority urban zones (A+, A, and B class areas), and “two-remote” units elsewhere. For low-voltage areas with controllable assets like rooftop PV or EV chargers, the plan advocates a “one transformer area, one terminal” principle to avoid redundancy, leveraging upgraded concentrators or next-generation fusion terminals capable of both rigid disconnect and smooth power modulation.
Crucially, the researchers emphasize a “minimal sensing plus digital inference” approach. Rather than blanketing every node with expensive sensors, the system will combine sparse high-fidelity measurements with advanced state estimation and AI-driven digital twins to reconstruct real-time grid conditions—a cost-effective path to full transparency.
Equally vital is the communications backbone. Fiber optics offer high security and bandwidth but are costly and vulnerable to construction damage, especially in overhead-line areas. Wireless solutions—4G, 5G, and dedicated private networks—provide flexibility but raise cybersecurity concerns, particularly when carrying control commands. The proposed solution is pragmatic and geographically nuanced: fiber dominates in dense, cable-based urban cores; 5G virtual private networks with hard slicing handle mixed urban and suburban zones; and wireless public networks, fortified with VPNs and network slicing, serve rural areas where control density is lower. On the low-voltage side, dual-mode HPLC (high-speed power line carrier) and HRF (high-speed radio frequency) technologies are being piloted to ensure robust, low-latency communication within transformer districts.
Perhaps the most systemic bottleneck lies in data silos. Real-time measurements from distribution automation, dispatch systems, and user information collection platforms currently reside in isolated repositories, hindering holistic visibility. The paper champions the creation of an enterprise-level real-time measurement center—a unified data lake that ingests short-cycle telemetry from all domains. Historical data would flow into a separate data middle platform, but the real-time hub would serve as the single source of truth for operational decisions. This “one grid, one data source” philosophy is essential for breaking down the walls between dispatch, equipment management, and marketing departments.
On the application front, the most radical shift is in control philosophy. Instead of a top-down command structure where provincial dispatch micromanages every inverter down to 380 volts, the new model embraces hierarchical autonomy. Physical microgrids, community energy systems, and virtual power plants become self-governing units that manage their internal balance while presenting a single, predictable interface to the wider grid. Dispatch retains oversight but delegates real-time adjustments to local controllers—reducing communication load and improving response speed.
For controllable loads, the architecture integrates dispatch automation, distribution automation, and the new load management system into a unified “source-grid-load-storage coordination center” within the production control zone. Control flows remain strictly within this secure perimeter. Meanwhile, non-control applications—asset management, customer service, energy analytics—leverage the real-time measurement center and data middle platform to deliver richer services without disrupting core operations.
This layered, federated approach aligns with global trends in grid modernization but is uniquely tailored to China’s scale and institutional structure. Unlike Western markets where third-party aggregators often lead innovation, China’s state-owned grid operators are driving the transformation from the center outward. The result is a highly coordinated rollout that prioritizes system stability while gradually opening doors for market participation.
The stakes are high. As distributed energy resources scale, the risk of reverse power flows, voltage fluctuations, and protection coordination failures grows. Without intelligent secondary systems, the grid could become less reliable even as it gets greener. Conversely, with the right architecture, distribution networks can become platforms for innovation—enabling peer-to-peer energy trading, dynamic tariffs, and grid-forming inverters that bolster resilience during outages.
Industry observers note that State Grid’s approach reflects a deeper strategic shift: from being a mere electricity transporter to becoming an orchestrator of energy ecosystems. The secondary system is the nervous system of this new organism—sensing, processing, and responding to stimuli in real time. Investments in this layer may not capture headlines like gigawatt-scale solar farms, but they are arguably more critical to the energy transition’s success.
Implementation won’t be easy. It requires massive capital expenditure, workforce retraining, and the harmonization of technical standards across provinces. Regulatory frameworks must evolve to accommodate new market roles like aggregators and microgrid operators. Cybersecurity must be embedded at every layer, from terminal firmware to cloud platforms.
Yet the momentum is undeniable. Pilot projects in Jiangsu, Zhejiang, and Guangdong are already testing elements of this architecture. The integration of EV charging networks with distribution management systems is advancing rapidly. And the push for “transparent grids”—where every transformer, line segment, and inverter is visible and controllable—is gaining traction as a core performance metric.
For international investors and energy executives, China’s grid transformation offers both caution and opportunity. The scale of investment is staggering—hundreds of billions of dollars over the next decade—but the technological roadmap is clear. Companies specializing in edge intelligence, secure communications, real-time data platforms, and distributed energy management systems will find fertile ground, provided they can navigate China’s unique regulatory and partnership landscape.
More broadly, China’s experience underscores a universal truth of the energy transition: the grid is no longer just steel and copper. It is software, data, and algorithms. The race to decarbonize isn’t won solely by building more wind turbines—it’s won by building smarter networks that can harness them effectively.
As DONG Chaowu and his colleagues conclude, the goal is not just a greener grid, but a more agile, resilient, and interactive one—one that can balance millions of decentralized decisions in real time while keeping the lights on for 1.4 billion people. In that vision, the humble distribution secondary system emerges not as a supporting actor, but as the star of the show.
Authors: DONG Chaowu¹, LOU Qihe², WANG Dengzheng², XIAO Zhihong¹, HAN Liu¹, XIN Peizhe¹
Affiliations:
¹ State Grid Economic and Technological Research Institute Co., Ltd., Beijing 102209, China
² State Grid Corporation of China, Beijing 100031, China
Journal: Electric Power Construction, Vol. 45, No. 8, August 2024
DOI: 10.12204/j.issn.1000-7229.2024.08.002