ABB Doc - IEC 61363-1 question

[good_news]

I work in marine business and normally use Paladin DesignBase for short circuit calculations. Now I'm having a go at ABB Doc since it is free and seems to be widely used. I will explain my question on a simple example.

Let's say that we draw this "network": generator -> cable -> breaker -> busbar and set all the parameters. If I then click to calculate the short circuit on the busbars Paladin will do it by "assuming" that the generator pre-load state was at rated kVA and cos phi, therefore with maximum EMF and producing maximum short circuit. It will do it even if there are no loads connected to the busbar. When I tried to the same in ABB Doc I first got some message that the busbar was unused, or something like that (don't remember exactly). So I figured that I should probably add some consumer, which I did. Eventually it turned out that the short circuit current on the busbars depended on the rating of that load. Mind you, I didn't add motors which contribute to the s.c. but some passive load. So it seems that before spitting out the s.c. result the program first does the power flow, based on the load it calculates the generator EMF, and then calculates s.c. Of course, electrically speaking it makes sense because that's how it works in reality. However, I wonder if there's some check box or option in ABB Doc that I can select which will calculate in the same way as Paladin, that is, spare me the additional work of drawing a load and adjusting it to match the generator rating?

By the way, is there anyone here using ABB Doc for ship / offshore s.c. calculations and how satisfied are you with it?

 

[dpc]

Short circuit current from a generator should not be dependent on pre-fault loading. But I don't know anything about ABB Doc. As you probably know Paladin DesignBase was acquired by EasyPower not too long ago.

 

[7anoter4]

In IEC 61363 the short-circuit current is calculated in some way different than
in IEC 60909-0 and the pre-load current is considered, indeed.

 

[good_news]

Yes, 61363 introduces active voltages dependent on the preload which determine the a.c. short circuit current, as attached by 7anoter4. In the marine world it is usual practice to calculate the short circuit with rated kVA and cos phi as preload. In reality, the difference in calculated short circuit between unloaded and fully loaded generator is not huge, but isn't negligible either. The difference corresponds approximately to xd'' per unit (say, xd'' = 0.15 means about 15% difference).