I have a question about the usage "Plot Profile" and the Max pu. voltage
and Min pu. voltage shown in the Summary:
As shown in the picture, the Max pu. voltage = 1.0472 and Min pu. voltage =
0.96137. However, if you see the profile, the lowest voltage is above 0.98
pu.
It is a test with a real circuit, not IEEE or EPRI standard circuit. So I
want to know how to explain this inconsistency?
(1) Yes, the statistics and the plotting are from the same simulation.
(2) No, I didn't run a new simulation. The "Plot Profile" following below the "Solve".
Do you have idea how to solve this inconsistency?
Thank you so much.
Yan
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
Please check the attached files. I created a portion of the test feeder
model which is easier to debug the problem.
Could you run the "Maui_SmallCase_Master.dss" file? As shown in the
attached picture, in the summary:
Max = 1.05 pu, and Min = 1.015 pu. However in the plot profile, the lowest
is above 1.04 pu.
Do you think it is caused by the voltagebases setting is wrong? Or some
other issues? It is a typical US feeder, the load is connected with
single-phase transformer.
If you need any other information, please let me know.
Please check the attached file. I created a portion of the test feeder model which is easier to debug the problem.
Could you run the "Maui_SmallCase_Master.dss" file? As shown in the attached picture, in the summary:
Max = 1.05 pu, and Min = 1.015 pu. However in the plot profile, the lowest is above 1.04 pu.
Do you think it is caused by the voltagebases setting is wrong? Or some other issues? It is a typical US feeder, the load is connected with single-phase transformer.
If you need any other information, please let me know.
I investigated this issue this afernoon, and found something may be useful to explain this problem. I also sucessfully reproduced this issue with IEEE 123 feeder.
When "plot profile", only line buses are plotted out. It begins with the first bus connected to the Energymeter, and ends at the line bus which is the farest from the substation.
In the Summary report, the Max and Min pu Voltage are from all the buses, not just the line buses, but also substation bus and transformer bus, etc. In my model, there are a lot of single-phase service transformers, the bus voltage magnitudes, such as voltage of the bus "669_XFRM_B" are not shown in the plotted profile, but is can be the lowest among all the buses.
Could you confirm what I think is correct or not?
Thank you.
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
In the profile plot voltage is displayed as a function of distance. So, the distance is dictated by the lines and the voltages will be the voltages at the line terminals. Normally, after a transformer, there is a line segment before reaching the load, but in your case, you are connecting the loads directly to the transformer. As you mentioned, the summary on the left of your screen takes the min/max values from all the circuit nodes, however, in spite of transformers are PDElements, the profile plot will only consider lines because of the reason explained above.
Best regards
Davis
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
In OpenDSS, the voltage rating of 2-and 3-phase elements are in kV LL. In 1-phase elements kV=the nominal voltage that appears across the terminals. So in a LN load, it will be KV LN but in a LL load it will be kV LL.
Also, in the voltage base calculation, the load at 645 is 208-V load so add 0.208 to the allowabe voltage bases (or define it separately with the SetkVBase command):
// ---------------------------Set the voltage Bases in phase-to-phase voltages------------------------------//
Set voltagebases=(69, 12.47, 0.416, 0.208)
Calcvoltagebase
So the pu voltages in the Summary are correct -- this includes all buses.
If you want to see the load buses in the Profile plot, add a short LINE between the transformer and the LOAD element. Make it long enough to be visible,
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
Thanks for finding this error. You are right that Transformer 645 and load 645 are 3-phase and others are single-phase. In this system, I didn't use the split-phase model, so the load and PV connected to the 240 V, not the 120 V. Hence, I corrected the code as:
Hi all,
I have a question about the usage "Plot Profile" and the Max pu. voltage
and Min pu. voltage shown in the Summary:
As shown in the picture, the Max pu. voltage = 1.0472 and Min pu. voltage =
0.96137. However, if you see the profile, the lowest voltage is above 0.98
pu.
It is a test with a real circuit, not IEEE or EPRI standard circuit. So I
want to know how to explain this inconsistency?
Thank you in advance.
Yan
Hello,
Are you plotting the profile and getting the statistics using the same simulation? Are you running a new simulation before plotting the profile?
Best regards
Davis
Hi Davis,
(1) Yes, the statistics and the plotting are from the same simulation.
(2) No, I didn't run a new simulation. The "Plot Profile" following below the "Solve".
Do you have idea how to solve this inconsistency?
Thank you so much.
Yan
Hi,
I can't reproduce it on my side, send me your script and I'll figure it out.
Best regards
Davis
Hi Davis,
Please check the attached files. I created a portion of the test feeder
model which is easier to debug the problem.
Could you run the "Maui_SmallCase_Master.dss" file? As shown in the
attached picture, in the summary:
Max = 1.05 pu, and Min = 1.015 pu. However in the plot profile, the lowest
is above 1.04 pu.
Do you think it is caused by the voltagebases setting is wrong? Or some
other issues? It is a typical US feeder, the load is connected with
single-phase transformer.
If you need any other information, please let me know.
Thanks a lot.
On Mon, Apr 15, 2019 at 11:17 AM Davis Montenegro davismont@users.sourceforge.net wrote:
Hi Davis,
Please check the attached file. I created a portion of the test feeder model which is easier to debug the problem.
Could you run the "Maui_SmallCase_Master.dss" file? As shown in the attached picture, in the summary:
Max = 1.05 pu, and Min = 1.015 pu. However in the plot profile, the lowest is above 1.04 pu.
Do you think it is caused by the voltagebases setting is wrong? Or some other issues? It is a typical US feeder, the load is connected with single-phase transformer.
If you need any other information, please let me know.
Thanks a lot.
Hi Davis,
I investigated this issue this afernoon, and found something may be useful to explain this problem. I also sucessfully reproduced this issue with IEEE 123 feeder.
When "plot profile", only line buses are plotted out. It begins with the first bus connected to the Energymeter, and ends at the line bus which is the farest from the substation.
In the Summary report, the Max and Min pu Voltage are from all the buses, not just the line buses, but also substation bus and transformer bus, etc. In my model, there are a lot of single-phase service transformers, the bus voltage magnitudes, such as voltage of the bus "669_XFRM_B" are not shown in the plotted profile, but is can be the lowest among all the buses.
Could you confirm what I think is correct or not?
Thank you.
Hi Yan,
In the profile plot voltage is displayed as a function of distance. So, the distance is dictated by the lines and the voltages will be the voltages at the line terminals. Normally, after a transformer, there is a line segment before reaching the load, but in your case, you are connecting the loads directly to the transformer. As you mentioned, the summary on the left of your screen takes the min/max values from all the circuit nodes, however, in spite of transformers are PDElements, the profile plot will only consider lines because of the reason explained above.
Best regards
Davis
Hi Davis,
Thank you so much for the detailed explaination. I really appreciate all your help and time.
Yan
I was also looking at this. Davis is correct: Plot Profile draws on LINE elements.
In addition, I found a couple errors associated with load at 645.
First in the Transformer definition:
In OpenDSS, the voltage rating of 2-and 3-phase elements are in kV LL. In 1-phase elements kV=the nominal voltage that appears across the terminals. So in a LN load, it will be KV LN but in a LL load it will be kV LL.
Also, in the voltage base calculation, the load at 645 is 208-V load so add 0.208 to the allowabe voltage bases (or define it separately with the SetkVBase command):
So the pu voltages in the Summary are correct -- this includes all buses.
If you want to see the load buses in the Profile plot, add a short LINE between the transformer and the LOAD element. Make it long enough to be visible,
Hi Roger,
Thanks for finding this error. You are right that Transformer 645 and load 645 are 3-phase and others are single-phase. In this system, I didn't use the split-phase model, so the load and PV connected to the 240 V, not the 120 V. Hence, I corrected the code as:
There is no 120V base in the system, but I will improve this model to use the split phase transformers.
Thanks a lot for your help.
Yan