Fraunhofer ISE, a renowned research institution, has made a significant announcement regarding a groundbreaking international test standard for photovoltaic (PV) inverters equipped with integrated arc fault detection systems. This new standard, known as IEC 63027, aims to address the limitations of the previous UL 1699B standard by incorporating more realistic operational simulations.
The shortcomings of the old standard, which has been mandatory for newly installed PV systems in the United States since 2011, became evident as it failed to detect numerous arcs. This was primarily due to the arcs not reaching the alarm threshold values or triggering false alarms. Recognizing the need for a more effective and accurate testing method, Fraunhofer ISE stepped up to develop the IEC 63027 standard.
To achieve a realistic and reproducible test environment, Fraunhofer ISE employs an electronic DC source as a PV simulator instead of real PV modules. By doing so, they can significantly minimize the risk of undetected arcs and false tripping. The institution explains that the test setup allows for the ignition of arcs under realistic conditions by utilizing a ball-and-socket joint comprising two tungsten electrodes. These electrodes are deliberately pulled apart at a defined speed, resulting in the initiation of a characteristic arc.
In order to ensure the measurement accuracy and eliminate any potential interference from the PV simulator, a filter network is connected between the inverter and the simulated PV system. The test setup takes into account crucial factors such as electrode distance and speed. The ability of the arc detector to function correctly relies on the time it takes for the inverter to shut off. Shorter switch-off times prevent excessive energy input into the faulty contact point, thus effectively reducing the risk of fire. According to Fraunhofer ISE, if the energy is between 200 and 750 joules and the switch-off time is under 2.5 seconds, the detector successfully passes the test.
Regarding the reconnection process after the arc detector has tripped, automatic reconnection is permitted up to four times within a 24-hour period. However, beyond the fifth tripping event, manual reconnection becomes necessary.
This new test bench, which is currently deployed at Fraunhofer ISE's TestLab Power Electronics, aims to expand the institution's range of services offered. The facility specializes in conducting accredited tests according to grid codes, efficiency measurements, and impedance spectroscopy investigations of inverters. Steffen Eyhorn, the head of TestLab Power Electronics, expressed his excitement about the new test bench, highlighting its potential to cater to industrial customers and meet their electronic power feed unit measurement and characterization needs.
Furthermore, Fraunhofer ISE recently inaugurated an outdoor solar technology test field in Germany. This state-of-the-art facility enables faster and more accurate evaluations of PV modules, further demonstrating the institution's commitment to advancing solar technology research and development.
