Is it permissible for the congregants in the Friday prayer, who were unable to follow the Imam due to a power outage on the upper floors, to pray Dhuhr instead?

If the congregant catches the bowing (rukūʿ) in the first rakʿah of the Friday prayer, and then an impediment occurs, he completes it as a Friday prayer individually. However, if he only catches the opening takbīr and does not catch the bowing, then he prays it as a Dhuhr prayer. This is based on the saying of the Prophet, peace and blessings be upon him: "Whoever catches one rakʿah of the prayer has caught the prayer."