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I'm seeing deviations in flat runs in dynamics when I break up my psspy.run() commands.

The reason I'm concerned is this behaviour is not expected. My understanding is that I can break a simulation up into multiple segments, even if nothing happens between the two.

For example, if I do a flat 30 second run with just one psspy.run() command, all machine angles are flat and are consistent with each other:

psspy.run(  tpause  = 30,
            nprt    = 0,
            nplt    = 5,
            crtplt  = 0
            )

However, if I do a 30 second run, broken up into multiple parts, one of the machine's angles starts to deviate after the first psspy.run() command (for 1 second of initialization):

psspy.run(  tpause  = 1.0,
            nprt    = 0,
            nplt    = 5,
            crtplt  = 0
            )
# [Do contingency actions here]
psspy.run(  tpause  = 30,
            nprt    = 0,
            nplt    = 5,
            crtplt  = 0
            )

I have a list of contingencies that is used as an input for a dynamics simulation loop. The first "contingency" is a no fault run to compare the other contingencies against. So in the code above, the [Do contingency actions here] segment would be:

• A non-operation for the "no fault" contingency.
• A series of actions for other contingency tests.