What technologies does Huawei use to ensure on rooftop and under rooftop security?

The exact extract asks what technologies Huawei uses to ensure “on rooftop and under rooftop security.” The correct answer is A, B, C. Rooftop security is mainly about reducing high-voltage DC risk and fire risk in the PV array. Rapid shutdown at the component level helps bring the rooftop PV side to a safer voltage state during emergencies, maintenance, or power outages. AFCI helps detect DC arc faults and shut down the system quickly before an arc can develop into a fire hazard. Under-rooftop security refers to household or building energy storage safety, where Huawei promotes multi-layer ESS safety protection from cells through packs, racks, system, and grid level. Huawei Smart Module Controller materials describe rapid shutdown for personnel and firefighting safety, Huawei AFCI materials confirm intelligent arc detection, and Huawei ESS materials describe five-layer integrated safety design. Because each option addresses a different safety layer, all three are correct. References: Huawei Smart Module Controller product page; Huawei AFCI Technical White Paper; Huawei Smart String ESS Solution.