Sungrow, TÜV Rheinland release long-term inverter reliability testing standards

Chinese inverter and storage system manufacturer Sungrow and German certification body TÜV Rheinland have jointly introduced what they describe as the world’s first quantitative corporate standards for assessing the long-term reliability of photovoltaic inverters, aiming to address growing concerns over equipment durability in utility-scale solar projects.

The standards establish a framework for evaluating inverter lifetime performance from both the component and system levels. According to the companies, the new specifications are intended to bridge the gap between conventional qualification testing and the real-world operating conditions faced by modern PV plants.

“Existing reliability qualification methodologies were not originally designed to fully capture the increasingly diverse and demanding operating conditions of modern PV plants, creating a gap between laboratory qualification and long-term field performance,” Sungrow said in a statement.

The new framework consists of two complementary standards that aim to provide a traceable, quantitative methodology linking component degradation to overall inverter performance.

The first, 2 PfG 3325, focuses on insulated-gate bipolar transistor (IGBT) modules, defining reliability testing methodologies for key power semiconductor components under stresses such as thermal and power cycling. The second, 2 PfG 3328 Part 2, establishes system-level procedures for reliability testing and lifetime assessment of power conversion equipment.

Sungrow said its SG510HX string inverter and associated IGBT modules are among the first products to be certified under the new specifications, providing an initial demonstration of the testing methodology.

The companies said the standards incorporate accelerated stress testing, failure mechanism analysis and lifetime modelling to estimate long-term operating performance.

The inverter reliability initiative follows a broader push by Sungrow and TÜV Rheinland to develop technical frameworks for renewable energy equipment. Earlier this year, the companies published a joint white paper outlining a risk-based approach to battery energy storage system (BESS) safety. The report argues that as storage projects scale to gigawatt-hour capacities, safety assessment must move beyond individual battery cells to encompass the entire system lifecycle, including design, testing, operation and maintenance.