Why is the single phase to ground short circuit never higher or even equal than the three phase short circuit
I have been testing the Three Phase Voltage Source Model 1, and found that while attaching it to a bus and running a short circuit, the single phase values never come close to the three phase ones, regardless of how much the impedance values of both the positive sequence and the zero sequence change, the three phase is always higher, Why does this happen in PSCAD while it doesn't in other software?
The model i used was the indicated source, a bus, the short circuit tool and a graphic element to see the current values.
Thanks a lot in advance
Status:
Open Jul 26, 2023 - 10:34 AM
Short Circuit, thevenin, single phase fault, Three phase fault
1answer
Answer
Sep 08, 2023 - 06:48 PM
You need to take a look at how the sequence networks are connected. A single phase fault will have all of the sequence networks connected in series while a three phase fault only involves the positive sequence network. This is generally why SLG fautls are less than 3LG faults. This is not always the case however. It is possible to have a 1LG fault that is higher than a 3LG.
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