Over the past decade, investigative reports into DC-side fire incidents in China's photovoltaic industry have routinely blamed improper construction and poor grounding. Following tragic accidents, the sector habitually pointed fingers at sloppy on-site work and lapses in operational maintenance. However, during research and analysis of multiple accident cases from 2023, the R&D team at Sungrow Power Supply Co., Ltd. discovered that many ignition points originated within the DC fuse devices themselves. They also uncovered a detail overlooked by the industry: the fuse rupture points appeared drawn and stringy, a typical sign of slow melting under low current, not the instantaneous explosive fracture caused by short-circuit high current.

This discovery shifted the focus from human error to deeper, hidden issues within existing standards. It wasn't a case of workers connecting wires incorrectly or a grounding malfunction. Instead, qualified fuses, defined under outdated standards, proved unable to effectively interrupt low-magnitude current faults in new scenarios characterized by larger power plants, growing complexity, and the integration of solar and storage systems. The assumption that DC-side safety is guaranteed as long as fuse selection meets standards—an assumption the industry has held for decades—collapsed in the face of real-world fault data. This presents a fundamental question for the photovoltaic safety standard system: when the context has changed but the standards still rely on outdated frameworks, who will drive the necessary redrawing?

From Option to Standard: Resetting the Baseline for Safety

In traditional photovoltaic systems, the DC-side fuse is considered the final physical defense. Yet, as power plants evolve toward higher power, higher voltage, and modular designs, fault characteristics are becoming increasingly complex and diverse. Risks such as sustained low-level overcurrent, arcing, and loose connections are challenging conventional protection logic. In response to these risks, Sungrow Power Supply Co., Ltd. has introduced active fuse technology that incorporates an active control mechanism. This system uses real-time status diagnostics to identify sustained low-level overcurrent, proactively activating a built-in energy conversion device. This forces the fuse to melt and stretch the arc, interrupting the fault circuit within milliseconds to achieve an active protection strategy.

Currently, this active fuse solution is standard equipment in Sungrow Power Supply Co., Ltd.'s core products, including its 1+X 2.0 modular inverters and matrix inverters. Cumulative project applications exceed 1.2GW, with over 10 related patents laid out. Unlike some companies that offer active fuses as an optional feature, Sungrow Power Supply Co., Ltd. has directly upgraded it to standard equipment at the factory. Under the premise of technological maturity, cost control, and thoroughly verified reliability, this safety capability should not be a differentiator that defines product tiers; it is a safety baseline that must be maintained. For customers, making it standard means they no longer need to deliberate over the trade-off of including this configuration during the bidding process. As safety control requirements for photovoltaic plants continue to rise, the transition of active fuses from a premium feature to an industry standard is inevitable.

Not Mere Compliance, But Redefinition: Leading the Charge in Safety Standards

In the photovoltaic industry, compliance often means meeting the lower limits of current standards, which is essentially a cost-minimization strategy. However, the evolution of active fuses from option to standard reveals a deeper industry pattern: what truly drives progress is never passive compliance with existing standards, but the proactive redefinition of "what it means to comply" through technological innovation. Looking at the evolution of international standards, the two revisions of IEC 62548-1 between 2016 and 2025 illustrate that new technologies are implemented first and, after accumulating enough experience, drive standards upgrades themselves. The new photovoltaic safety standards comprehensively enhance the protection system on the DC side.

Undeniably, iterative standards set a baseline for safety, but standards should never be seen as a ceiling or a finish line. They act more like a floor, specifying the minimum entry requirements the industry must follow. The core value of Sungrow Power Supply Co., Ltd.'s active fuse is precisely this: raising the level of that floor. This represents not just a technological upgrade of a single component, but a collective re-evaluation within the entire photovoltaic industry of safety as a fundamental issue. Of course, transitioning safety features to standard in practice faces industry trade-offs. In a competitive bidding environment, owners and EPC contractors often prioritize initial construction investment; active protection components add incremental cost, and the tendency to favor immediate costs over long-term safety losses remains a practical obstacle to widespread adoption. Only when safety capabilities are truly translated into product competitiveness will the evolution of standards stop relying solely on top-down mandates and potentially progress naturally from the bottom up, marking a sign of industry maturity.

Technology Pushing Standards: Three Trends to Watch

In the photovoltaic field, the misalignment between technology and standards often sees technology running ahead. This isn't necessarily a disruption of order, but rather a way to force an upgrade of that order. The emergence of Sungrow Power Supply Co., Ltd.'s active fuse is pushing the safety standard system toward deep iteration in three directions.

First, safety protection cannot rely on a single component operating in isolation; it needs to be supported by a "Prevention-Diagnosis-Isolation (PDC)" three-stage prevention and control model. Prevention means identifying potential risks in advance, diagnosis means real-time monitoring for signs of faults, and isolation means immediately cutting off the fault circuit once an issue occurs. Devices such as combiner boxes, inverters, insulation monitors, and arc detection systems must no longer work in isolation but collectively form an integrated protective network. This also sets new requirements for standards: they cannot just test components individually in a laboratory but must also verify whether the entire system can respond quickly during actual faults.

Second, the safety mindset is shifting from passively meeting specifications to actively preventing risks. Previously, the focus of standards was on whether the system could protect after a fault occurred. The new direction represented by active fuses is whether faults can be prevented before they happen, moving safety assessment to a pre-event warning stage. Finally, safety verification is transitioning from static indicators to dynamic testing in realistic scenarios. Standard-setting must also be tested under complex and variable real-world operating conditions. Previously, fuse testing was conducted in fixed laboratory environments, but actual plant operating conditions vary widely and are highly unpredictable. Sungrow Power Supply Co., Ltd., in collaboration with TÜV Rheinland, has built a 4.8MW large-scale test platform in a real power plant to simulate over 15 extreme scenarios including short circuits, arcing, and loose connections, comprehensively testing protective performance. Safety is never an achievement completed by a single test or certification; it is an endless process of redefinition. In the evolution of safety rules, technology is the most solid foundation.