Hi,
When working with MATPOWER and setting up your power system case file (such as `case9.m`), there are several common issues that can lead to non-convergence during power flow analysis. Here's a checklist and some tips to help you troubleshoot your `case9.m` file:
1. Verify Data Entries:
- Bus Data:
- Ensure that the bus types are correctly specified: 1 for PQ bus, 2 for PV bus, and 3 for the reference (slack) bus.
- Double-check that all voltage magnitudes and angles are in per unit (p.u.) and degrees, respectively.
- Ensure that load (Pd, Qd) and generation (Pg, Qg) values are correctly converted to p.u. based on the system base power.
- Generator Data:
- Check that the generator's active and reactive power limits (Pmax, Pmin, Qmax, Qmin) are reasonable and in p.u.
- Ensure that generator voltage setpoints are correct.
- Branch Data:
- Confirm that branch impedances (resistance and reactance) and line charging susceptance are correctly specified in p.u.
- Verify that the branch tap settings are correct, especially if there are transformers in the system.
2. Base MVA:
- Ensure that the system MVA base (`baseMVA`) is correctly set in your `case9.m` file. This value is crucial for converting all other values to p.u.
3. Check for Data Consistency:
- Make sure that there are no mismatches between the number of buses, generators, and branches specified.
- Ensure that all buses referenced in the branch and generator data exist in the bus data.
4. Initial Guesses:
- Sometimes, providing good initial guesses for voltage magnitudes and angles can help with convergence. Ensure that these are reasonable.
5. MATPOWER Options:
- Check the MATPOWER options for the power flow solver. Sometimes adjusting tolerances or using a different solver can help.
6. Common Errors:
- Ensure there are no negative or zero values where they are not allowed (e.g., negative impedances or zero base MVA).
- Verify that the slack bus is correctly identified and that there is only one slack bus.
Debugging Tips:
- Run MATLAB with Debugging Enabled: Use MATLAB's debugging tools to step through your code and verify each part of your data.
- Compare with Known Working Cases: If possible, compare your `case9.m` with a known working case file to spot potential discrepancies.
- MATPOWER Output: Carefully read the output and warnings from MATPOWER when it fails to converge.
