Submission 152
Spatial Variability and Parameter Sensitivity of RoCoF Following System Splits in Low-Inertia Power Systems
02 GIW26-152
Presented by: Simon Eberlein
Cascading failures in interconnected power systems can culminate in a system split, causing severe active power imbalances and critical local frequency and rate-of-change-of-frequency (RoCoF) excursions within the resulting
islands. While normative withstand requirements and protection schemes such as under-frequency load shedding and RoCoF relays are typically derived from
center-of-inertia (COI) or otherwise aggregated frequency signals, local RoCoF at individual buses can deviate substantially from this aggregate
value. This paper investigates the spatial and parametric behavior of local RoCoF following a system split using a meshed ten-bus test system that replicates the dynamics of a larger interconnected system after separation. Parameter studies covering voltage, inertia magnitude and spatial distribution, breaker opening delay, active power imbalance, boundary power exchange, and line length reveal that the maximum local RoCoF varies non-monotonically with distance from the split, peaking close to the separation boundary, reaching a minimum at the electrical center of the island, and rising again at remote buses due to the system's oscillatory dynamics. Averaged frequency signals are found to systematically underestimate the true local maximum RoCoF. The filter time constant used in RoCoF post-processing and the inertia distribution are
identified as the parameters with the strongest influence.