I run my loadflow using fixed slope newton raphson but it converges after 15 iterations, does it mean that my results on the model is unstable?
Hi JConto,
I have initialized my dynamic data and initial conditions are ok but I got some reports for my overloaded machines see below. How do I go about reducing solving this overloaded machine problems? OVERLOADED MACHINE SUMMARY: BUS# X-- NAME --X BASKV ID MW MVAR QMAX QMIN ETERM CURRENT PF MVABASE X T R A N GENTAP ZONE AREA SWING 505 OLORUNSOGOG10.500 1 41.9 23.0 23.0 -15.0 0.9474 50.4 0.8766 52.3 1 1 2501 KAINJI8 16.000 1 57.5 -29.8 25.0 -30.0 1.0000 64.8 0.8876 85.0 1 3 2701 KAINJI10 16.000 1 57.5 -29.8 25.0 -30.0 1.0000 64.8 0.8876 85.0 1 3 3001 KAINJI9 16.000 1 57.5 -29.8 25.0 -30.0 1.0000 64.8 0.8876 85.0 1 3 16013 OLORUNSOGOG15.000 1 41.9 23.0 23.0 -15.0 0.9339 51.2 0.8766 52.3 17 1 16029 OLORUNSOGON10.500 1 126.0 60.0 60.0 -40.0 0.9786 142.6 0.9029 157.0 13 1 16030 PAPALANTO GE10.500 1 126.0 60.0 60.0 -40.0 0.9786 142.6 0.9029 380.0 13 1 16034 OLORUNSOGOG15.000 5 41.9 23.0 23.0 -15.0 0.9339 51.2 0.8766 52.3 13 1 16035 OLORUNSOGOG13.800 1 41.9 23.0 23.0 -15.0 0.9339 51.2 0.8766 52.3 13 1 16036 OLORUNSOGOG13.800 5 41.9 23.0 23.0 -15.0 0.9339 51.2 0.8766 52.3 13 1 16037 OMOTOSHOGTB15.000 5 41.9 23.0 23.0 -15.0 0.9681 49.4 0.8766 52.3 13 2 16038 OLORUNSOGOG15.000 1 41.9 23.0 23.0 -15.0 0.9339 51.2 0.8766 52.3 13 1 16039 OLORUNSOGOG15.000 5 41.9 23.0 23.0 -15.0 0.9339 51.2 0.8766 52.3 13 1 26000 OMOTOSO G-BU15.000 2 41.9 23.0 23.0 -15.0 0.9939 48.1 0.8766 52.3 22 2 26006 OMOTOSO GEN 15.000 1 41.9 23.0 23.0 -15.0 0.9939 48.1 0.8766 52.3 20 2 26007 OMOTOSHOGTB15.000 5 41.9 23.0 23.0 -15.0 0.9681 49.4 0.8766 52.3 23 2 36012 SHIROHYD1 16.000 1 150.0 79.0 79.0 -30.0 0.9787 173.2 0.8848 174.0 30 3 86012 AFAM VI - 4 11.500 1 200.0 124.0 124.0 -83.0 1.0315 228.1 0.8499 210.0 80 8 86032 ALAOJIGTB1 15.000 5 112.5 -48.8 84.4 -56.3 0.9247 132 ...
I have tried running the dynamic simulation but after introducing a fault, the psse freezes and tries to reboot itself or it says network not converge at time =0.02. I have my initial conditions ok, I have removed all gen P and Q limits but I still do not have dynamic solution. I am really confused
All machines in you overload table are at their Qlimit. A fault imposed higher reactive infusion, but having no margin, the system enters into a voltage collapse condition. Try reducing the load in the system and perform a PV analysis to identify the voltage margins. test: Add an Statcom.
Hi Jconto, I have tried everything you said but still no head way. Please send me your email address so you can look at it and see how you can assist. thank you
dynamic flatstart is a time-consuming effort. I will take a look at your data set but unless it is an obviuos fix, do not expect a quick answer. My email is jcpotencia@mail.com
Hi Jconto, Please do know the procedure to model the PV system on PSSE for the dynamic solution?
Load flow convergence in a given number of iterations does not correlate with model instability. It is simple an indication of how far the initial network states (V and angles) are from producing a mismatch (in P and Q) within the tolerance specified in the tool. Model instability is tested with dynamic tools, mainly, a dynamic simulation.
When a dynamic simulation gives 'network not converged' errors, you can try the following:
review the (newest) models parameters for anomalies. Data entry errors.
lower delta t, integration stepsize.
check that bus voltages (V, angle) and Gens P & Q are within limits in the base case. Check the 'SUSPECT CONDITIONS' entries after the STRT activity.
Start from a known dynamic set that 'flatstart', it gives var's flat lines to a no-disturbance test, and then sequentially add the new models and repeat the flatstart until the problem is identified or no problem is found. Once all new models are added and you still get a flatstart, then you are ready for a full dynamic simulation. Post your findings.
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Thank you for your reply. I ran the loadflow and it converge in 15 iterations after which I proceeded to run the dynamic simulation with all dynamic models included. I followed the normal process of dynamic simulation but I keep getting the results on 'network not converged at time'.