Need advice on grid-tied system in Rio de Janeiro

jbcarioca

I know I'm distant  from NAZ, but you seem to have very good advice here.
I am trying to have my new house be primarily grid-tied but the voltage varied hugely in the local grid which has nominal 127.220/60, in my case three phase. The 127 routinely varies from 110 to 135 and power fails often.
Hence I am trying to power my house solely from the battery intermediated inverter providing pure sine wave and constant voltage. 

I know this is not really a huge problem, except that this is rarely done in my area so I need some technical advice to make sure I select the correct equipment and vendor. FWIW, both solar panels from BYD and others are made here, and batteries from CATL, BYD and a variety of other providers are readily available. There si a complete Sunpower range available as well.

I'm hoping to learn more.

FWIW, I went 100% off-grid with a solar system in an island in the Bahamas 30 years ago. I knew more then, but most fo those vendors no longer exist and everything else is different. It feels horrible to be so ignorant now!

Dave Angelini

Is this DIY or will there be an installer? 

Thirty years ago there was Trace inverter chargers and they sold to Xantrex who sold to Schneider Electric Solar division. ( Schneider solar inverters).  Schneider has a world presence and if you pick the correct battery you can run a 3 phase XW pro system that is closed loop between the BMS and the power system.

Closed loop (Soc based) is great with big systems. All settings in/out are pre-programmed and you can save energy charging as well as get it done faster than open loop which is voltage based.

No matter what you do, you can learn here and you need to know it all in your part of the world no matter who installs this. It will not be inexpensive!       
 https://solar.se.com/us/en/


Good Luck !

BB.

Just an FYI... While this forum was founded and is funded by NAZ (nothern Arizona Wind & Sun). Everyone here (including me) are just volunteering our help to others on the forum. You do not have to be a customer or NAZ/NAWS to post here.

Neither me, or others here, speak for NAZ.

Much of the solar design questions start with what are your needs... You can design a battery based solar system that will power "ANY" modern home these days (say 300-1,000 kWH per month)... Or a "smallish" off grid capable system starting around 100 kWH per month (3.3 kWH per day). Not cheap, but at least economically viable for many folks (enough to run a full size fridge/freezer, LED lightning, small well/water pump, laptop computer, LED TV, clothes washer a couple times a week)...

A big issue is that a well designed and operating off grid solar power system costs around $1-$2+ per kWH to run... And in most countries, that is several times the cost of Utility power. Which makes running a battery based solar power system "large enough" to run your home just too expensive for running as a backup power system (i.e.... More or less, off grid solar is "use it or lose it" energy wise... You can only store 2-4 days of energy (say you lose power every 2 weeks--That is 2 days of stored energy vs 12 days of "lost usage".

You can design a more complex system that will interact with your AC utility power. Charge the battery bank to 100%, and run your home appliances and even "send energy back to the grid" (if legal in your area) so you, at least, are not "losing" money/harvest when the grid is up.

These "Hybrid Systems" (utility interactive/Grid Tied capable AC battery based inverters) are pretty common these days, so having that feature is almost "cost free" these days (part of the basic inverter function).

Anyway--Back to your requirements... How long/often are the outages. Single phase 120/240 VAC 60/50 Hz systems are the cheapest--If you had to do 3 phase--That can add a lot of costs (i.e., possible 3 AC inverters, one for each phase).

Things you can do is decide what needs power during an outage... Just a fridge, LED Lighting, laptop, TV, water pump--And let the other stuff be off during an outage (A/C, heating, hot water, electric cooking, full size well pump, etc.). You are creating a "protected power" subpanel for the home/emergency power system.

And you could (if possible for your home) add a backup genset for longer outages where you want the home fully powered (A/C, washer/dryer, hot water, water pumping, shop power, desktop computer, etc.) that you fire up when needed... A genset that runs a few days to a few weeks a year, is usually less expensive than a pure solar backup power system (i.e., you really want to use the solar power 9+ months a year to make solar+battery system cost effective).

Anyway--Your thoughts?

-Bill