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FLOW1 function output not matching with Load Flow Solution

asked 2022-11-22 07:20:53 -0600

CPReddy gravatar image

updated 2022-11-22 07:22:09 -0600

I have written a power plant controller model in PSSE. I need to initialize the PPC model with remote branch flow. I used the FLOW1() function to get the active and reactive power flow of the remote branch. Somehow there is a difference in the results between the steady-state model and this function output. The difference is very minor (0.02 MVAR). Due to this, I am getting initial suspects in the PSSE model, which is not accepted by many utilities.

CALL FLOW1(M+1,L+2,L+3,L+4) Q = VAR(L+3)

from load flow Q = 16.0042 MVAR, but from VAR(L+3) it is 15.99409 MVAR. Even though the difference is very small but it will show as a suspect.

Kindly help me to resolve this issue.

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answered 2022-11-24 10:22:06 -0600

perolofl gravatar image

You don't have exactly the same solution in load flow and at initialisation. The generators and loads are converted the load flow is solved with TYSL. This explains the difference in the line flow values. Very normal and shouldn't cause any initial conditions suspect.

Which STATE has suspect conditions? What kind of block is it (lag, integrator, washout, etc)?

What are the STATE and DSTATE values?

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answered 2022-11-22 11:53:46 -0600

Hello, are you initializing with some setpoint or VAR reads the Q directly. If you are initializing with Q value user defined, then make sure the Q is selected from the same end. I would suggest try adding a line with zero impedance and try initializing it.

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Hi, the model is initialized from the load flow solution. I think we should solve the network solution first and read the Q value from the solution. This may solve the issue. But I don't have any idea to do it. In the case of the current injection model, normally we do this when IFLAG is true.

CPReddy gravatar imageCPReddy ( 2022-11-22 20:37:08 -0600 )edit

Hello, You can solve the network before initialisation and make sure the convergence tolerance are met and also Q at branch is within the limits of PPC specified limits.

Berwin gravatar imageBerwin ( 2022-11-23 01:34:41 -0600 )edit

I didn't get your answer exactly. Could you please give me a piece of code to do it.

CPReddy gravatar imageCPReddy ( 2022-11-23 05:21:11 -0600 )edit

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Asked: 2022-11-22 07:20:53 -0600

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Last updated: Nov 24 '22