UPS for whole house on short periods

[BillP]

Good afternoon to all members,

I have tri-phase 230V electric utility at my house, and the neighborhood is growing fast with new buildings on the last year. In recent months we have suffered short blackouts (around 5 seconds) a couple of times a day. I am concerned these blackouts can damage my appliances in the near future.

To cover this, I am interested for a solution to cover the whole house energy requirements for a short time (20 to 30 seconds). My consumption has an average of 850 kWh year average, with 1200 kWh on hot months. Also, I would like to incorporate over/undercurrent protection to the house, as brownout are rare (but had happened before)

Is there a method to calculate and dimension an UPS for this application? Surge/Brownout/blackout protection all combined.

Thank you in advance for your comments on this question.

[Brad_C · Accepted solution]

On 30/6/2020 3:54 AM, Osvaldo said:

Is there a method to calculate and dimension an UPS for this application? Surge/Brownout/blackout protection all combined.

You'll need to size it based on your peak demand, and in this instance your peak demand is going to be the size of your inbound circuit protection. For example in my house I have a 3 phase 32A service. So I'd need to size a UPS capable of sustaining 32A on each phase simultaneously. That's 32x240x3 ~= 23KVA. That'd be a pretty large and expensive UPS.

I'd hazard a guess and say you really don't want to do that. Try looking at rationalizing your UPS down to the devices you really need to protect. In my place I've used an SU2200 and reticulated UPS outlets to cover the computers, network gear & TV/Stereos. Yes, my mother in law plugged her hairdryer into the red outlet and popped the breaker, but that's an education thing rather than infrastructure.