V36 export a .raw and then load a .raw, lose short circuit data impedance
As I am still leaning and using the student version so I don't think I have access to other resources, I will continue noting issues here. I will get my license when I am confident using the student version.
I have solar generators and am trying to do the static short circuit calculations, so I need to set the short circuit data, to limit the short circuit current delivered by the inverter to the value controlled by the inverter ( I think that is how you do it).
If I export the data as a .raw file with all options selected other than exporting by name, and reload the file, the generator short circuit data is not reloaded.
Should it matter, I have the solar generator setup as follows. Renewable Fixed Q based on WPF Power factor set o 0.950 X source set to 9999
My notes re the value to be set are:
PSS/E short-circuit modules rely on a voltage source behind an impedance. We must calculate an equivalent impedance that results in the correct current limit.
PSS/E has the MVA values entered as real values, you need to work out the maximum current, convert it to a pu value, and use this to get the pu z value.
In our case we will use 1.2 times the full load current as the short circuit current.
At 0.660 MVA and 0.4 kV the full load current is 0.953 kA = 953 amps.
The short circuit current = 0.953 *1.2 = 1.143kA
The current base = Ibase = MVAbase/sqrt(3)*Vbase
Ibase = 100/(sqrt(3)*0.4) = 144.3376.
The base is for kA.
So Isc pu = 1.143/144.3 = 0.00792
And Zsc pu = 1/0.00792 = 126
As an aside:
The code psspy.shortcircuitz_units(1) outputs the message “SHORT CIRCUIT IMPEDANCE UNITS option setting set to PHYSICAL UNITS”, this changes the output data ( Thevenin impedance), not the method of inputting the impedance on the short circuit page, which remains as pu values.
I know it seems strange using PSS/E for a toy solar systems like this, but that is where the Australian industry has got to.
