Deviation of Post-Fault Steady State of a Power System Model from Initial Conditions in Simulations of Self-Cleared Faults

摘要

In dynamic simulation of a self-cleared fault, it is expected that the initial conditions and the post-fault steady state conditions should be the same. However, simulations with large power system models have provided evidence that deviations of the post-fault steady state conditions from the initial conditions may exceed thresholds set in industry requirements. This paper discusses industry requirements and outlines factors likely causing excessive deviations: nonlinearity of the mathematical model; severity of the fau distortions introduced by numerical integration; initial and end transients; unintended changes in the system topology and operation; and real simulation environments. Assessments of deviations observed in power system simulations have suggested that industry requirements may need to be less stringent.