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U.S. Department of Energy
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Long-term system dynamics simulation methods. Final report

Technical Report ·
OSTI ID:5835145

The focus of long-term dynamic simulations is to analyze the effects of wide excursions of voltage, frequency and power flows for extended periods of time on the bulk power system. The emphasis on modeling the sequence of system events over an extended period of time that follows a major disturbance distinguishes long-term dynamics from transient and midterm stability analysis where the effects of inter-machine oscillations on synchronous machines is the primary focus. The assumption of a uniform system frequency during quiscent system conditions makes it possible to use a numerical stepsize of one or more seconds for long-term studies, as opposed to a fraction of a cycle for transient/midterm stability, and to simulate the voltage and frequency effects of such system events as automatic load shedding and unit tripping for long periods of time. Both the time frame and the type of system events of interest in long-term dynamic studies establish the modeling and simulation requirements for a long-term program and the need for system data to validate the models and program. The sequence of system events that occur during the long-term time frame may introduce step changes in the system, i.e., load shedding, which cause transients that must be modeled on the transient stability time scale. This is the basis for the requirements that a long-term program have an adequate interface with a transient stability program.

Research Organization:
Boeing Computer Services Co., Tukwila, WA (USA)
OSTI ID:
5835145
Report Number(s):
EPRI-EL-3894; ON: TI85920514
Country of Publication:
United States
Language:
English