Test Cases Library of Power System Sustained Oscillations

Natural oscillation case ND_9 (Back to the homepage)

This case contains single source at generator 11 contributing to three different unstable modes.


System model:

  • All generators are in GENCLS model.
  • Parameter D for generator 11 equals -10.
  • Parameter D for all other generators equals 4.
  • All loads are in constant MVA model.


    • Disturbance:

  • A three-phase short circuit is added at bus 79 at 0.5s and cleared after 0.05s.


    • Small signal analysis:

  • The local mode at 1.63Hz has a negative damping of -0.40%.
  • The inter-area mode at 0.69Hz has a negative damping of -1.81%.
  • The inter-area mode at 0.46Hz has a poor damping of -0.86%.
    • Mountain View

    Figure 1. WECC 179-bus power system