How much fault contribution from a converter?

[pwrtran]

Hi folks

I like to get some help on this - does anyone have some idea on how to calculate the fault contribution from a photovoltaic-converter generation that is connected to a distribution system?

Thanks!

 

[dpc]

Generally it's very limited because the inverter shuts itself down.

 

[pwrtran]

Hi dpc

Couple more questions based on your comments:

1) does the converter shut down by protection or by the nature of attenuation?
2) what's typical momentary short circuit current in pu compared to its FLC?
3) what is a division point of over load and over current in terms of %

Thanks

 

[davidbeach]

Many inverters have a maximum current output that is only 1.1 to 1.2 times full load. Apply a short circuit to the output of the inverter and it will shut down on undervoltage, not overcurrent.

 

[dpc]

As David Beach said, these things cannot put out much fault current even when they try. One big problem with UPS inverters is that they cannot clear a downstream molded case circuit breaker of any size without transferring the load to the mains via a static switch.

The inverter protection circuitry shuts it down on undervoltage.