Grid Tie and Voltage Fluctuations

[mcc]

We had almost made final decisions of setting up a 3kW Grid Tie System when suddenly our city hit by a storm and since then the voltage is fluctuating a lot.

I want to know, when we have a grid tie system, its voltages are dependent on the Grid Voltage, will the fluctuation cause the Grid Tie inverter to show symptoms as well?

[Sunking]

We had almost made final decisions of setting up a 3kW Grid Tie System when suddenly our city hit by a storm and since then the voltage is fluctuating a lot.

I want to know, when we have a grid tie system, its voltages are dependent on the Grid Voltage, will the fluctuation cause the Grid Tie inverter to show symptoms as well?

Solar is a current source and will not effect voltage one little bit.

[inetdog]

We had almost made final decisions of setting up a 3kW Grid Tie System when suddenly our city hit by a storm and since then the voltage is fluctuating a lot.

I want to know, when we have a grid tie system, its voltages are dependent on the Grid Voltage, will the fluctuation cause the Grid Tie inverter to show symptoms as well?

When the grid voltage is unstable one of two things will happen:

1. The GTI will track the changes in the grid voltage and/or grid frequency and not be affected at all in terms of power output, or
2. The GTI will decide that the voltage of frequency have varied outside the upper or lower limits programmed into the GTI (and possibly user-changeable) and shut down its power generating function temporarily. Only after the grid voltage has remained within tolerances for five minutes will the GTI start to deliver power again. This five minute delay is also used when the GTI first wakes up as solar input becomes sufficient in the morning or after shading or when the GTI is first connected to the grid.

[SunEagle]

Grid voltage fluctuation is a pretty broad term that describes a lot of abnormal conditions that can happen on the power grid.

As inetdog stated, a GTI has a number of Grid power parameters it looks at to decide if it should continue working or not. Some of those parameters are "Frequency Shift", under or over frequency, under or over voltage as well as other types of transients that occur on a large power distribution system.

It would be hard to say if your Grid Tie system would continue to work or not through all of these "fluctuations".

[mcc]

This mean we can safely say that Grid Tie system may not work during low voltage or high voltage?

[billvon]

This mean we can safely say that Grid Tie system may not work during low voltage or high voltage?

Indeed it will likely not work during low or high voltage conditions.

[inetdog]

This mean we can safely say that Grid Tie system may not work during low voltage or high voltage?

You can find out easily enough by looking at the specifications for each type/model of GTI you are interested in. At a minimum I would expect them to handle +/- 10% from the nominal power and for many models those limit voltages can be be changed in the field.
A lot depends on just how low or high the POCO voltage goes. There are limits on what a POCO is supposed to deliver, based on the nominal voltage, and even in a brownout they will do their best not to go below those limits. To drop below that point would expose them to damage claims on motors and other sensitive loads. They would just go a rolling blackout instead at that point.