Load flow convergence problem

Hello,

I have a problem with the attached Simulink Scheme. The generator has been put as a Swing bus, while the load as a PQ bus I have tried to run a load flow simulation on the scheme, but it seems I have no convergence.

What I have noticed is that: -By removing the PI section line, while maintaining all the rest, the load flow actually converges to a solution. Of course, same goes if remove both PI section line and the transformer. -By reducing the load (up to 14MW and up to 14Mvar) the system still converges, even if I keep the PI section line. -By replacing the load (a R-L parallel load) with an R-L series load (of equal P and Q) the system still converges.

Could you please help me figuring out what the problem is? Thanks in advance, Davide

[Franklin Ngo]

Hello,

I checked your system. Your problem is about transient stability. The maximum power: Pmax = E'*Eb/X ( for more details, please read the chapter 13. transient stability. - 13.1 an elementary view of transient stability - book: [prabha kundur] power system stability and control). Your power is too large, then your impedance have to be reduced. Please check the attached file.

[Kamilu Sanusi]

@Franklin Ngoplease I am similar problem, on IEEE 9 bus system, if i set my load as constant impedance load, the active power injected at the generator bus becomes greater than the specified mechnical power input. The active and reactive power PL & QL of the load also rises.

Please what is the likely problem, all other loads are okay

Thank you

Answer 1

[Willim]

Thank you for sharing the problem. I would like to contact you if you would like to help each other in this problem.