Frequency stability provision from battery energy storage system considering cascading failure s with applications to separation events in Australia

The increasing penetration of non-synchronous generators, accompanied by retiring/displacement of synchronous generators has created a number of new operational issues in the Australian National Electricity Market (NEM) network, such as low-inertia conditions. Low-inertia power systems are likely to experience relatively large frequency variations following a generation/load mismatch. This is evidenced by a recently occurred event in the Australian National Electricity Market (NEM) grid, which led to cascading failures and electrical separation of the two states of Queensland and South Australia from the rest of the NEM. This paper first provides an extensive description of the event occurred on 25^th August 2018, whose high-level dynamic behaviour was simulated in a NEM reduced test system. Secondly, the use of grid-scale battery energy storage system (BESS) in providing primary frequency response (PFR) is investigated as a potential countermeasure to cascading failures. Simulation results show BESS could have potentially avoided under-frequency load shedding (UFLS).