Huawei, Mazer and UFSM test AFCI and prove its effectiveness against electric arcs

Huawei, in partnership with the Federal University of Santa Maria (UFSM) and Mazer Solar, has successfully completed a proof of concept to validate the performance of the AFCI (Arc Fault Circuit Interrupter) function in photovoltaic inverters. The test aimed to the performance of the arc fault protection system, a requirement of the IEC 63027:2023 standards and INMETRO ordinance No. 515/2023.

The initiative was conducted at the UFSM laboratory, approved by Inmetro, and allowed the effectiveness of AFCI in Huawei inverters to be proven, reinforcing the company's commitment to the safety and reliability of photovoltaic installations.

AFCI Application

Em Photovoltaic systems, direct current (DC) voltage typically operates between 600 and 1000V. Under these conditions, especially in rooftop installations, the risk of fire represents the greatest threat both from an economic point of view and to the safety of people. In the event of a fire, the arc flash in CC is widely recognized as the main cause of the problem.

This phenomenon occurs when electric current es through an insulating medium — such as air — overcoming its resistance and causing a dielectric breakdown between two points of the same conductor or between different conductors. Situations such as poor in connectors or faults in the insulation of DC cables can trigger this type of arc, drastically increasing the temperature in the affected region, with records ranging from 700°C to 3000°C.

In the event of an imminent electric arc, it is essential to interrupt the power supply as quickly as possible to ensure the safety of the installation and people. Based on this principle, the POC (proof of concept) tests strictly followed the compliance criteria established by the IEC 63027:2023 standard and the ordinance Inmetro No. 515/2023.

POC Details

Due to the complexity of measuring the effectiveness of AFCI, the UFSM laboratory facilities were used since it has Inmetro approval to perform this type of test. The scope of the test encomes the technical procedures of the IEC63027:2023 standard.

AFCI Test Routine

With the equipment previously listed, it was possible to establish a test routine to evaluate the protection of the direct current (DC) circuit against faults due to electric arc in photovoltaic systems. From this structure, the PVAG LAB laboratory was able to simulate the occurrence of series arcs, according to the criteria defined in the IEC 63027:2023 standard.

PVAG LAB is composed of different control modules, which allow to reproduce realistic operating conditions. The ACEM (arc emulation device) has an adjustable module that allows to precisely control the arc actuation time. The ILM (impedance line module) simulates longer cables, while the ILDM (impedance and decoupling module) reproduces scenarios with PV strings of different lengths, short or long.

With the devices energized, the test was performed, leading to the following results:

We can observe the attenuation and spectrum reading, as well as the operating time. In other words, the protection can turn off the inverter even before the electric arc appears or before the imminence of the arc can stabilize.  

Test Conclusion

After analyzing the functionality of the AFCI function offered by Huawei in residential inverter models, we can conclude that the solution is effective in ensuring the safety of the installation when there is an imminent possibility of electric arc formation. Furthermore, by complying with the requirements of the IEC 63027:2023 standard, the AFCI system meets international requirements.

Read also

Proof of Concept: See How Rapid Shutdown (RSD) Works

The opinions and information expressed are the sole responsibility of the author and do not necessarily represent the official position of the author. Canal Solar.