I havent played the game in awhile but when you first enter the generator room you have to try to turn on the generator, it should need a battery.
If you already have the battery placed in the consoles and try to activate the generator the fuse should blow.
exit the generator to find the storage room ( i think there are maps that you can use placed around the tunnels.)
after you manage to reach the storage room there should be a broom.
after you replace the old fuse you need to rotate the valves on the consoles
From left to right the valves are going to be called
5,4,3,
----2
----1
after you rotated all the valves move up to the generator and pull the lever and than you are done!