TRACON Controller reported an equipment loss that left the facility without power for a very long time.

Narrative

I had just come on the shift. We were briefed that we would be on generator power through the entire shift. At approximately XA:45 I had 2 Aircraft coming into ZZZ on vectors; one aircraft on final talking to Tower; one aircraft that just departed ZZZ1 head to ZZZ2 in the climb. I had also taken one handoff from ZZZ2 coming into our airspace; not talking to that aircraft yet. And lastly one aircraft south of ZZZ3 that was on their way to ZZZ4. About 3 minutes after Tech Operations put us on generator we had experienced a total power failure. All of the equipment that we use to control traffic including all communication ability was lost. Scopes shut down completely; and there was no power to go into EFSL (Emergency Full Service Level) as a back up. There was no power to the FAA Jacks. I was able to get communication via portable emergency radio to tell the aircraft on final and close to the airport RADAR contact lost. I told one aircraft about the aircraft they were sequenced behind to follow them inbound. I was unable to talk to the other aircraft in the airspace due to the distance from the Tower. We were combined up TRACAB for mid shift configuration.The Local Controller left the Tower immediately to run down and see if the TRACON still had power. When he got down there; there was no power. He ran outside to tell Tech Operations that we had a total power failure. Tech Operations then proceeded to put us back on commercial power. And power was reestablished after about 5 minutes.Even though the power came back on; the Tower TDW's (Tower Display Workstation) did not return for nearly 40 minutes. Radar scopes did comeback up shortly after power was reestablished. I was able to tell ZZZ ARTCC to hold everyone; and I was able to verify that ZZZ2 had the handoff with the aircraft that was head their way. I broadcasted to that aircraft and told them to contact ZZZ2 Approach. The Local Controller was able to get a scope up and running; and configured to take radar in the TRACON. I gave the best briefing I could. One Tower TDW finally started working but most of the equipment was OTS for a lengthy time. Tech Operations did work on the equipment throughout the night to get it up and running. At around XE:00 am we were able to get the second scope in the Tower to work and were able to reconfigure to TRACAB status. I was briefed this was happening. I also spoke to the Manager about it a day before and asked if we would be in ATC Alert. The response was no. I feel this was not taken to the precautionary level it should have been. I feel that this was a stroke of luck that we were in between two heavier traffic periods. Had this been 5 minutes later the traffic complexity would have been much more serious with all the late arrivals and traffic flying through the airspace.This cannot happen. I feel a full investigation should happen. Nobody should have to go through that while working traffic. It put multiple lives at stake and put unwanted risk into the system. This is not the first time lack of following checklist has lead to equipment failing. This need to be elevated beyond this district. This should not happen at all; period.