Test Cases Library of Power System Sustained Oscillations

Natural oscillation case ND_5 (Back to the homepage)

This case contains single source, one unstable inter-area mode and two poorly damped local and inter-area modes, where the oscillation source is generator 11.


System model:

  • All generators are in GENCLS model.
  • Parameter D for generators 6 and 11 equals 3 and -8, respectively.
  • 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 30 at 0.5s and cleared after 0.05s.

  • Small signal analysis:

  • The local mode at 1.63Hz has a negative damping of -0.48%.
  • The inter-area mode at 0.70Hz has a negative damping of -0.19%.
  • The inter-area mode at 0.46Hz has a poor damping of 0.69%.
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    Figure 1. WECC 179-bus power system