Hefei, China – November 20th – Sungrow, a globally leading provider of PV inverters and energy storage systems, today announced the successful conclusion of a comprehensive field test for its new 1+X 2.0 modular inverter, conducted in partnership with TÜV Rheinland. The test results validate the inverter's Intelligent DC-Side Full-Scope Safety Solution, showcasing major strides in active protection, fault identification, and system-level safety for utility-scale photovoltaic plants.

In large-scale PV plants, the DC-side frequently represents the system's most vulnerable segment. Its intricate network of wiring and numerous connection points means that even a minor fault can lead to significant equipment damage or, in worst-case scenarios, fire. Industry statistics reveal that nearly 90% of plant incidents originate on the DC-side. Sungrow's 1+X 2.0 modular inverter confronts these challenges head-on with an upgraded safety framework built on the PDC model—Prevent, Diagnose, and Contain—delivering a proactive and precise approach to safeguarding the entire DC-side.

The collaborative field test rigorously assessed the inverter's performance against four common DC-side risks: short circuits, arc faults, overheating from loose connections, and low-magnitude overcurrents.

Short Circuit Test: Millisecond-Level Safe Shutdown

Traditional combiner boxes often rely on copper fuses for protection, which can be slow to disconnect during a short-circuit fault due to copper's high melting point. This delay can cause persistent arcing, potentially burning through the fuse box instantly and damaging adjacent components. Sungrow's combiner box utilizes silver fuses, which have a lower melting point, as its core protective element. This, combined with a multi-breakpoint topology design, dramatically enhances both arc suppression and response speed.

During testing, engineers replaced one silver fuse in the test unit with a standard copper fuse to compare their performance under an identical short-circuit fault. When the fault was triggered, the copper fuse produced an intense arc flash and was completely burned through. In stark contrast, the silver fuse disconnected the circuit within milliseconds. The fuse body remained intact with no signs of arcing, achieving a clean and safe power cutoff.

Arc Fault Test: 32 ms Detection and Shutdown

Arc faults rank among the most destructive hazards on the DC-side. At high voltages, arc temperatures can instantly surpass 3000°C, posing a severe fire risk. In the field test, when an arc fault was intentionally initiated, the combiner box accurately identified the arc and shut down the circuit within 32 milliseconds. Simultaneously, the inverter coordinated a shutdown across all combiner boxes within the same unit, swiftly isolating the hazard and preventing its spread. This ensured no equipment damage or ignition occurred.

"Arc faults within parallel strings present a complex electrical challenge, as their signals are often masked by system noise, making them difficult to detect with conventional algorithms," explained a Sungrow expert. "Our pioneering DC parallel arc protection technology, equipped with an intelligent diagnostic algorithm, adaptively adjusts protection thresholds for various scenarios and operating conditions. This allows it to accurately identify arc faults and disconnect to ensure plant safety."

Loose-Connection Overheating: Targeted Isolation Without Sacrificing Yield

Loose connections at DC terminals are a common yet hard-to-detect issue in utility-scale plants. Their initial temperature rise is typically slow and gradual, often evading traditional overcurrent protection systems, which can eventually lead to inverter shutdowns due to overtemperature. The 1+X 2.0 modular inverter employs high-precision NTC temperature sensors and intelligent algorithms to continuously monitor temperatures, provide early warnings, and isolate potential faults.

In the test, a loose connection was deliberately created. The temperature at the affected PV terminal contact rose slowly at a rate of approximately 0.5–2°C per minute before stabilizing. The 1+X 2.0 system monitored these changes in real-time, issued a warning about 15 minutes after the temperature exceeded the threshold, and precisely disconnected the faulty branch—all without impacting the operation of the rest of the array.

Low-Magnitude Overcurrent Test: Sub-2ms Cutoff with Zero Damage

Traditional fuse-based protection relies on high fault currents to trigger disconnection. For hidden faults like low-magnitude overcurrents, fuses often cannot react promptly, allowing prolonged current stress that may damage critical components such as IGBTs. Sungrow has pioneered a pyro-fuse protection scheme that integrates three core mechanisms beyond traditional fuses: active arc control, high-efficiency cutting, and powerful arc suppression.

During the field test, a short-circuit fault was induced. The results demonstrated that the 1+X 2.0's system disconnected the faulted circuit in a precise 1.472 milliseconds. Following the disconnection, the inverter itself remained undamaged and restarted without issue. By comparison, a traditional fuse solution took 526 milliseconds to disconnect, underscoring the pyro-fuse scheme's superior speed and protection accuracy.

Furthermore, the pyro-fuse system is capable of detecting up to 15 different categories of DC faults, enabling proactive, forced disconnection to ensure the inverter's integrity.

TÜV Rheinland expert Tian Xingxin, who witnessed the entire field testing process, confirmed that the 1+X 2.0 modular inverter and its Intelligent DC-Side Full-Scope Safety Solution successfully passed all challenges. He emphasized the system's leading capabilities in proactive detection, precise disconnection, and system-wide protection. "This not only provides a verifiable technical pathway for ensuring DC-side safety in utility-scale plants but also sets a valuable reference for the industry in pursuing higher-level safety standards," Tian noted.

As solar projects worldwide trend towards larger scales and higher system voltages, DC-side safety demands are becoming increasingly stringent. With its 1+X 2.0 modular inverter, Sungrow is introducing a new, demonstrable safety benchmark for the industry, giving plant operators and investors greater confidence in long-term operational reliability.