Just got a new idea for a project during our tropical storm after the power went out. What if i had an arduino do everything i just did? Flip main breaker off, turn on the generator, make sure it was running, and gradually connect and turn on individual circuits. I've been running though a scheme of attack for the past hour and it seems possible.
I would think i would need:
arduino mega
reset-able fuse for each circuit
Project enclosures for both inside and outsite by the generator
remote transmission method, wireless (x bee) or wired. (may be even use the existing wire going to the outside power box)
miscellaneous buttons and switches.
arduino backup battery (12V, like the apc back up batteries)
multiple 5v relays to switch over 120v/240v relays
some other stuff i haven't thought of.
The plan of attack is to mount radioshack project boxes (the large ones) on the interior wall and outside with a 16 x 2 lcd. it would constantly monitor the voltage level of the mains power supply. when the power level drops then it would kick over into a standby mode and beep every second power is off. after ten seconds it would send a command to the outside station and start the generator. after the signal level of the output is consistent (to some degree) it would then begin to activate switches to pull off mains to the generated power. and continue to monitor the mains power supply. when it comes back on, it will wait thirty seconds then begin to one by one switch over back to mains. waits another thirty seconds (just in case) and begins to shutdown the generator.
Anyone else ever thought of this? Ideas? incite? all is appreciated. Yes, i am using this as a blog of some sort
That's totally possible, Commercial emergency power systems work like that.
Basically you would need a a transfer switch, so that you can select line power or gen power, you need to make absolutely certain that you cannot backfeed power into the grid so that no one gets hurt and your not trying to run the neighborhood off your gen. You will need to decide what circuits you want to power on emergency power.
After the power fails, you will switch the transfer switch, start the gen, possibly warm up the gen, connect the gen to the house, monitor grid power for return, decide on a transfer scheme to return grid power * ,
When you reconnect grid power there is something you need to keep in mind, commercial systems always check the phase so that it will switch only when the power matches, if you don't do that you can have a severe power spike when reconnecting. This will give you a bump-less transfer if you're fast enough, transferring on the zero crossing will also make this more seamless and prevent spikes/surges.
The other method is to disconnect the gen and then reconnect the grid power after disconnecting the gen and waiting for a couple seconds.
One thing to remember is not to start or stop your genset under load, always let the genset come up to speed and stabilize before you connect loads, and always let it stabilize after you disconnect loads before you shut it off.
Most systems also will wait for grid power to stabilize before switching back, perhaps 30 seconds ...
perhaps you will want a few minute cool down for the genset as well
Dont forget a about a 1s delay before starting the gen, that will prevent the gens from starting due to the power company switching transfer stations ( those quick bumps that makes your lights flicker )
you could also get the genset to run up every week for 15 mins for a maintenance run or once a month for 30mins etc ...
or once a month for 30mins etc ...