How to run a grid-tie inverter on off-grid when the grid fails?

To run a grid-tie inverter on off-grid when the grid fails, you will need a reference power source like a diesel generator and a solar power control device like ZED Advance. When the grid fails, you can run your grid-tie solar power plant in synchronization with a diesel generator and a solar power control device will protect the generator from the reverse power of the solar power plant by controlling the solar power generation as per the load requirement.

The below diagram shows the connection of the solar inverter with the grid power having a net meter.

To run a grid-tie inverter during the power cuts, you will be required generator [as reference power source], ZED Advance [solar power control device], transfer switch with sets of current transformer and local network [for monitoring].

The below diagram shows the typical connection of the solar power control device with the gird-tie inverter.

1. When the grid power fails, you need to transfer the power from the grid power to the generator via a transfer switch then start the generator.

2. The current transformer in the transfer switch, measure the load on the generator and transfer the power feedback to the solar control device.

3. Solar power control device, analyse this feedback and control the power generation of the grid-tie inverter.

4. If the solar power generation is higher than the load requirement, then the solar control device will reduce the output power of the inverter.

5. And when the load requirement is higher than the solar power generation, then the solar control device won’t affect the output power of the inverter.

6. When the grid power resume, then you need to stop the generator first. After that transfer the power source from the generator to the grid via the transfer switch.

7. When the transfer switch in on-grid power. The current transfer won’t send any feedback to the solar control device. Hence solar control device won’t affect the power.

Which make of grid-tie inverters are compatible with solar power control devices?

All major grid-tie solar inverters like ABB, SMA, Hitachi, Consul Neowatt, Huawei, Solar Edge, Kaco, Delta, Solis, Kirloskar, polycab, Sungrow, Growatt, Fronius, REFU Sol, Schneider, Zever solar and many more are compatible with Solar power control device.