Limit advice

AEMO is responsible for the calculation of the limit equations in the Victorian region as a part of its Victorian transmission network service provider (TNSP) role. These limit equations describe the capability of the power system under both system normal and outage conditions in the Victorian region.

Oscillatory stability limits are a NEM-wide phenomenon and AEMO calculates these limits in consultation with other TNSPs.

This transfer limit advice document describes the oscillatory stability limits under system normal and outage conditions for the NEM.

Tasmania and South Australia (either operating as an island or at risk of islanding) can operate at low inertias, unlike the other NEM regions. Low inertia can have a large effect on FCAS requirements, therefore AEMO calculates these requirements taking into account both the inertia and demand. Due to this being a complex, iterative calculation AEMO has used multiple variable regression analysis to calculate these requirements.

System strength reflects the sensitivity of power system variables to disturbances. It indicates inherent local system robustness, with respect to properties other than inertia. This document summarises the combinations of synchronous generators that would provide sufficient system strength to withstand a credible fault and loss of a synchronous generator, at different non-synchronous generation levels.