Test Cases Library of Power System Sustained Oscillations

Forced oscillation case F_6_2 (Back to the homepage)

In this forced oscillation case, the source of oscillations is at generator 79.

System model:

Generator 79 is in GENROU model.

All other generators are in GENCLS model.

Parameter D for all generators equals 4, except for generator 79 whose D equals 0.

All loads are in constant MVA model.

Small signal analysis:

All natural modes have reasonably good damping.

External force:

Forced oscillation is injected into excitation system as a rectangular wave at generator 79 with a fundamental frequency at 0.2Hz.

Figure 1. Block diagram of the external force

Figure 2. WECC 179-bus power system

Generator angle oscillations for the case F_6_2 are shown in Fig.3. Many generators across the system have comparable magnitude of oscillations. Magnitudes of excited harmonics are different for different generators which makes practically impossible to identify the source of oscillations looking at the graph.

Figure 3. Generator angles in the case F_6_2. Blue curve represents the source of oscillation at generator 79.