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Contact the manufacturer of each type of equipment and request updated/modern models (not obsolete or old default models). For governor, ask for deadband parameters and corresponding model with deadbands. From the exciter manufacturer also get data for the over-excitation limiter and under-excitation limiter and corresponding models. For the stabilizer, models are found on tuning report of such stabilizer.
If only generic models are available, do extensive model validation tests matching measured/recorded (pmu or better) machine performance curves with PSSe model simulation response to same event.