First-in-Industry Field Test: Sungrow 1+X 2.0 Modular Inverter Leads DC-Side Safety Innovation

HEFEI, China, Nov. 21, 2025 /PRNewswire/ -- Sungrow, the global leading PV inverter and energy storage system provider, announced the successful completion of a comprehensive field test conducted jointly with TÜV Rheinland on its latest 1+X 2.0 modular inverter. The results verify the inverter's Intelligent DC-Side Full-Scope Safety Solution, demonstrating significant advancements in active protection, fault identification, and system-level safety for utility-scale PV plants.

In utility-scale PV plants, the DC-side is often the most vulnerable part of the entire system. With complex wiring and numerous connection points, even a minor issue at one point can cause equipment damage or, in severe cases, fire. Industry data indicates that nearly 90% of plant incidents originate from the DC-side. Sungrow's 1+X 2.0 modular inverter addresses these challenges with an upgraded safety architecture based on the PDC model—Prevent, Diagnose, and Contain—offering a proactive and precise way to enhance safety across the entire DC-side.

The joint field test evaluated performance under four typical DC risks: short circuits, arc faults, loose-connection overheating, and low-magnitude overcurrent.

Short Circuit Test: Millisecond-Level Safe Power Cut

Traditional combiner boxes using copper fuses as the protection device often fail to disconnect rapidly under short-circuit fault conditions due to copper's high melting point. This can lead to sustained arcing, which may instantly burn through the fuse box and damage nearby components. Sungrow's combiner box uses silver fuses with a lower melting point as the core fuse material. Combined with a multi-breakpoint topology design, it significantly improves arc suppression and response speed.

During the test, the team replaced one silver fuse in the test combiner box with a copper fuse to compare their behavior under the same short-circuit fault. When the short circuit fault was triggered, the copper fuse produced a strong arc flash and was burned through, while the silver fuse completed disconnection within milliseconds. The fuse body remained intact with no arcing, achieving a safe and clean power cut.

Arc Fault Test: 32 ms Detection and Disconnection 

Arc faults are among the most destructive risks on the DC side. At high voltage, the arc temperature can instantly exceed 3000°C, creating a serious fire hazard. During the field test, when an arc fault was deliberately triggered, the combiner box precisely detected the arc and disconnected within 32 milliseconds. At the same time, the inverter coordinated the disconnection across all combiner boxes in the same inverter unit, quickly isolating the risk and preventing fault propagation.  fault propagation with no equipment damage or ignition occurred. 

"Arc faults in parallel strings are electrically complex, and the signals are easily drowned out by noise, making them difficult to detect with traditional algorithms," explained a Sungrow expert. The expert added that Sungrow's pioneering DC parallel arc protection technology, equipped with an intelligent arc diagnosis algorithm, can adaptively adjust protection thresholds for different scenarios and operating conditions, accurately identify arc faults, and disconnect to ensure plant safety.

Loose-Connection Overheat: Isolation Without Yield Loss

Loose connections at DC terminals often go undetected in utility plants. Their initial temperature rise is slow, making it difficult for traditional overcurrent protection to detect anomalies in time, which can lead to inverter overtemperature shutdowns. The 1+X 2.0 modular inverter uses high-precision NTC temperature sensors and intelligent algorithms to continuously monitor temperatures, issue early warnings, and isolate potential faults.

During the test, a loose connection was deliberately triggered. The temperature at the tested PV terminal contact rose slowly at about 0.5–2°C per minute and gradually stabilized. The 1+X 2.0 monitored these changes in real time, issued a warning approximately 15 minutes after the temperature exceeded the threshold, and precisely disconnected the affected branch without impacting the rest.

Low-Magnitude Overcurrent Test: Less than 2ms Cutoff, No Damage

Traditional fuse solutions rely on fault current magnitude for disconnection. Under hidden faults such as low-magnitude overcurrent, fuses often cannot react in time, and prolonged current stress may damage key components like IGBTs. Sungrow pioneered the pyro-fuse protection scheme, which integrates three core mechanisms on top of traditional fuses: active arc control, high-efficiency cutting, and strong arc suppression.

During the field test, a short-circuit fault was deliberately induced. The results showed that the 1+X 2.0 disconnected the faulted circuit precisely in just 1.472 milliseconds. After disconnection, the inverter remained undamaged and restarted smoothly. By comparison, a traditional fuse solution took 526 milliseconds to complete disconnection, demonstrating the pyro fuse scheme's significant advantage in speed and protection accuracy.

Besides, the pyro fuse can detect up to 15 categories of DC faults, enabling proactive forced disconnection to secure inverter integrity.

TÜV Rheinland expert Tian Xingxin, who witnessed the full field tests, affirmed that the 1+X 2.0 modular inverter and its Intelligent DC-Side Full-Scope Safety Solution successfully passed all challenges. He highlighted the system's leading capabilities in proactive detection, precise disconnection, and system-level protection. This not only provides a verifiable technical pathway for ensuring DC-side safety in utility-scale plants, but also offers a reference for the industry to explore higher-level safety measures.

As global solar projects move toward larger scales and higher system voltages, DC-side safety requirements continue to intensify. The Sungrow 1+X 2.0 introduces a new, verifiable safety standard for the industry, offering plant operators and investors enhanced assurance for long-term reliability.

About Sungrow

Sungrow, a global leader in renewable energy technology, has pioneered sustainable power solutions for over 28 years. As of June 2025, Sungrow has installed 870 GW of power electronic converters worldwide. The Company is recognized as the world's most bankable PV inverter and energy storage company (BloombergNEF). Its innovations power clean energy projects across the globe, supported by a network of 520 service outlets guaranteeing excellent customer experience. At Sungrow, we're committed to bridging to a sustainable future through cutting-edge technology and unparalleled service. For more information, please visit: www.sungrowpower.com.

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