If i want to build a system with an off-grid inverter for backup reasons, which will only work when a utility loss occurs, and with an on-grid inverter to work normally during grid presence, can i parallel the same PV strings on their PV inputs?
On that case, when there is sun the PV has energy, therefore, it will inject to the grid and at the same time it will charge the batteries through the off-grid inverter.
The AC circuits of both inverters are separated, the only thing in parallel and connected with each inverter are the PV strings.
Hi
In a hybrid system, you can run an off-grid inverter to generate the grid, then use a grid-tied inverter to run most or all the power. This is a scenario we use in off-grid design when the solar must be located over 20m from the battery store or the power demand is large in the daytime when the sun is out. This is the most efficient way to use the power.
Yes, PV in parallel with on or off line inverters could be used in parallel with grid to optimize the day time demand of the industrial load areas are in practice…..
Dear Gustavo Gushiken:
It's about Hybrid solar systems:
Hybrid solar systems combine the best from grid-tied and off-grid solar systems. These systems can either be described as off-grid solar with utility backup power, or grid-tied solar with extra battery storage.
If you own a grid-tied solar system and drive a vehicle that runs on electricity, you already kind of have a hybrid setup. The electrical vehicle is really just a battery with wheels.
-- Advantages of hybrid solar systems:
1. Less expensive than off-grid solar systems
Hybrid solar systems are less expensive than off-grid solar systems. You don’t really need a backup generator, and the capacity of your battery bank can be downsized. Off-peak electricity from the utility company is cheaper than diesel.
2. Smart solar holds a lot of promise
The introduction of hybrid solar systems has opened up many interesting innovations. New inverters let homeowners take advantage of changes in the utility electricity rates throughout the day.
Solar panels happen to output the most electrical power at noon – not long before the price of electricity peaks. Your home and electrical vehicle can be programmed to consume power during off-peak hours (or from your solar panels).
Consequently, you can temporarily store whatever excess electricity your solar panels in batteries, and put it on the utility grid when you are paid the most for every kWh.
Smart solar holds a lot of promise. The concept will become increasingly important as we transition towards the smart grid in the coming years.
-- Equipment for hybrid solar systems:
Typical hybrid solar systems are based on the following additional components:
--Charge Controller
--Battery Bank
--DC Disconnect (additional)
--Battery-Based Grid-Tie Inverter
--Power Meter
Battery-based grid-tie inverter:
Hybrid solar systems utilize battery-based grid-tie inverters. These devices combine can draw electrical power to and from battery banks, as well as synchronize with the utility grid.
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Also Equipment for off-grid solar systems
Typical off-grid solar systems require the following extra components:
--Solar Charge Controller
--Battery Bank
--DC Disconnect (additional)
--Off-Grid Inverter
--Backup Generator (optional)
--Solar charge controller
--Solar charge controllers: or charge regulators or just battery regulators. The last term is probably the best to describe what this device actually does: Solar battery chargers limit the rate of current being delivered to the battery bank and protect the batteries from overcharging.
Good charge controllers are crucial for keeping the batteries healthy, which ensures the lifetime of a battery bank is maximized. If you have a battery-based inverter, chances are that the charge controller is integrated.
--DC disconnect switch:
AC and DC safety disconnects are required for all solar systems. For off-grid solar systems, one additional DC disconnect is installed between the battery bank and the off-grid inverter. It is used to switch off the current flowing between these components. This is important for maintenance, troubleshooting, and protection against electrical fires.
--Off-grid inverter:
There’s no need for an inverter if you`re only setting up solar panels for your boat, your RV, or something else that runs on DC current. You will need an inverter to convert DC to AC for all other electrical appliances.
Off-grid inverters do not have to match phase with the utility sine wave as opposed to grid-tie inverters. Electrical current flows from the solar panels through the solar charge controller and the bank battery bank before it is finally converted into AC by the off-grid-inverter.
@https://www.solarreviews.com/blog/grid-tied-off-grid-and-hybrid-solar-systems
I hope it will be helpful...
Best wishes...
It is better to have one p.v. string in series and parallel and only one type of inverter
if p.v. power is less than battery charging power, first charge battery then supply the grid.
otherwise apply power to battery and grid simultaneously .when the battery is charged then supply the grid.
you need a smart controler to distinguish the above mentioned states.
thank you
Thanks for the answer, Kitmo .. !
Could you give more details about the lifetime of the inverter associated with the commutation?
Thanks...
If the power angle of two inverters are the same you can parallel tow or even more than two inverters.with this adjusting the power angle of two inverter respect to a common point in the network will be the same and you haven't circulating current.try to set the voltage angle of off grid inverter as on grid inverter
thank you