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Voitcus
Voitcus
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As Andy aka wrote, there is x" (xd") which is sub-transient reactance in d-axis of the generator and it is the basis machine parameter and should be allowed to enter (I can't believe it is not). This value is required if you're going to simulate short-circuits, so maybe it is allowed to insert in other tab (it should be in "Fault").

The other idea is that you inserted a generator-transformer unit while you should insert a generator only.

However, if you're going to calculate power flows, this value is not necessary and can be omitted (so why then is it given on your picture?).

Because the text on the picture says something about "power swings", perhaps you are to simulate swings, so no xd" should be used but xd' rather. Typically the xd' is about 1.5-2 greater than xd", for 100-200 MVA generators xd" = 0.25, (for smaller units it can be 12%), xd' = 0.4, so obviously data given is not xd'. (Maybe "power swings" text is only to tell that the busbar is not a reference node).

The values of "Internal Sequence Impedances" are: negative - use x2, zero - use x0, and perhaps x" could be positive seq., however it should be x1 which is xd and it's usually about 200-250% of the generator's base reactance that you'd calculate from U^2/S (probably you need to convert them to pu's as default value is 1, so type just what you have on your picture).

For the line sequence impedances they are given on your picture as eg. 0.2+j0.5 Ohm/km, so you calculate line reactance as 0.5 Ohm/km multiplied by line length, as well as resistance and also capacitance given as y = 3.3e-6 S/km, so multiply by line length.

EDIT

It mostly depends on what kind of simulation you would like to perform. Perhaps the software you're using has two modes of operation, Power Flow and Transients or something like this. In the first case, as I've written above, you'd not need xd" so you are not allowed to input it. Perhaps you should only switch the simulation type from "static" to "dynamic".

However, you have not provided any information about the type of your simulation (there is no question on the picture, either).

As Andy aka wrote, there is x" (xd") which is sub-transient reactance in d-axis of the generator and it is the basis machine parameter and should be allowed to enter (I can't believe it is not). This value is required if you're going to simulate short-circuits, so maybe it is allowed to insert in other tab (it should be in "Fault").

The other idea is that you inserted a generator-transformer unit while you should insert a generator only.

However, if you're going to calculate power flows, this value is not necessary and can be omitted (so why then is it given on your picture?).

Because the text on the picture says something about "power swings", perhaps you are to simulate swings, so no xd" should be used but xd' rather. Typically the xd' is about 1.5-2 greater than xd", for 100-200 MVA generators xd" = 0.25, (for smaller units it can be 12%), xd' = 0.4, so obviously data given is not xd'. (Maybe "power swings" text is only to tell that the busbar is not a reference node).

The values of "Internal Sequence Impedances" are: negative - use x2, zero - use x0, and perhaps x" could be positive seq., however it should be x1 which is xd and it's usually about 200-250% of the generator's base reactance that you'd calculate from U^2/S (probably you need to convert them to pu's as default value is 1, so type just what you have on your picture).

For the line sequence impedances they are given on your picture as eg. 0.2+j0.5 Ohm/km, so you calculate line reactance as 0.5 Ohm/km multiplied by line length, as well as resistance and also capacitance given as y = 3.3e-6 S/km, so multiply by line length.

As Andy aka wrote, there is x" (xd") which is sub-transient reactance in d-axis of the generator and it is the basis machine parameter and should be allowed to enter (I can't believe it is not). This value is required if you're going to simulate short-circuits, so maybe it is allowed to insert in other tab (it should be in "Fault").

The other idea is that you inserted a generator-transformer unit while you should insert a generator only.

However, if you're going to calculate power flows, this value is not necessary and can be omitted (so why then is it given on your picture?).

Because the text on the picture says something about "power swings", perhaps you are to simulate swings, so no xd" should be used but xd' rather. Typically the xd' is about 1.5-2 greater than xd", for 100-200 MVA generators xd" = 0.25, (for smaller units it can be 12%), xd' = 0.4, so obviously data given is not xd'. (Maybe "power swings" text is only to tell that the busbar is not a reference node).

The values of "Internal Sequence Impedances" are: negative - use x2, zero - use x0, and perhaps x" could be positive seq., however it should be x1 which is xd and it's usually about 200-250% of the generator's base reactance that you'd calculate from U^2/S (probably you need to convert them to pu's as default value is 1, so type just what you have on your picture).

For the line sequence impedances they are given on your picture as eg. 0.2+j0.5 Ohm/km, so you calculate line reactance as 0.5 Ohm/km multiplied by line length, as well as resistance and also capacitance given as y = 3.3e-6 S/km, so multiply by line length.

EDIT

It mostly depends on what kind of simulation you would like to perform. Perhaps the software you're using has two modes of operation, Power Flow and Transients or something like this. In the first case, as I've written above, you'd not need xd" so you are not allowed to input it. Perhaps you should only switch the simulation type from "static" to "dynamic".

However, you have not provided any information about the type of your simulation (there is no question on the picture, either).

Source Link
Voitcus
Voitcus
  • 499
  • 3
  • 11

As Andy aka wrote, there is x" (xd") which is sub-transient reactance in d-axis of the generator and it is the basis machine parameter and should be allowed to enter (I can't believe it is not). This value is required if you're going to simulate short-circuits, so maybe it is allowed to insert in other tab (it should be in "Fault").

The other idea is that you inserted a generator-transformer unit while you should insert a generator only.

However, if you're going to calculate power flows, this value is not necessary and can be omitted (so why then is it given on your picture?).

Because the text on the picture says something about "power swings", perhaps you are to simulate swings, so no xd" should be used but xd' rather. Typically the xd' is about 1.5-2 greater than xd", for 100-200 MVA generators xd" = 0.25, (for smaller units it can be 12%), xd' = 0.4, so obviously data given is not xd'. (Maybe "power swings" text is only to tell that the busbar is not a reference node).

The values of "Internal Sequence Impedances" are: negative - use x2, zero - use x0, and perhaps x" could be positive seq., however it should be x1 which is xd and it's usually about 200-250% of the generator's base reactance that you'd calculate from U^2/S (probably you need to convert them to pu's as default value is 1, so type just what you have on your picture).

For the line sequence impedances they are given on your picture as eg. 0.2+j0.5 Ohm/km, so you calculate line reactance as 0.5 Ohm/km multiplied by line length, as well as resistance and also capacitance given as y = 3.3e-6 S/km, so multiply by line length.