by Andrew Dillon, Chief Executive Officer, Energy Networks Australia
In June, almost 50 million people were left without power in Argentina. Energy Networks Australia CEO Andrew Dillon takes a closer look at the events causing this catastrophic blackout, and considers the likelihood of an event like this occurring in Australia.
How can a significantly interconnected grid with high levels of synchronous generation just collapse?
That’s what happened on Father’s Day, 16 June 2019, in Argentina. At 7.07am, a failure on the grid left about 48 million people in the dark.
The learnings from Argentina’s mistakes may help Australia strengthen its own grid.
What happened to make the grid go down?
Expenditure on Argentina’s grid had been cut for some time. Transmission faults were known to occur causing partial blackouts.
The grid collapse, in this case, was catastrophic. Customers were left in the dark and were requested to limit water use. The extent of the disruption can be seen by a massive drop in demand, Figure 1, which slowly recovers 12 hours later.
Preliminary views suggest that problems on two 500kV transmission lines disrupted the flow of electricity from two hydro-schemes.
A short circuit disconnected a 500kV transmission line that runs from the city of Colonia Elía to Belgrano in Buenos Aires. It appears at the same time an automated system disconnected a 500kV line that runs from Mercedes to Colonia Elía. A third 500kV transmission line had been out of service since mid-April to relocate a tower.
Water levels in the Yacyreta Dam and Salto Grande Dam were high. Early Sunday morning both of these hydroelectric facilities were producing electricity at near maximum capacity, although demand was low.
A further 1000MW was being imported across the interconnector from Brazil on a high voltage direct current link. This meant that with one line down, high levels of power were being transferred south on the remaining lines.
It is possible that transient instability occurred in the north-west region and the Yacyreta hydro plant (3700 MW) tripped, possibly causing a fast frequency drop. It appears that the Salto Grande hydro plant (1900 MW) also tripped due to instability.
The 500kV lines to the Buenos Aires load centre went down, due to the large deficit in generation. Frequency plummeted, and the system collapsed.
It would be expected that the automated systems in place to shed load or generation to suit demand should have isolated the issue associated with a short circuit. It is not yet clear why this didn’t occur.
The Argentinean President Marci has promised a full investigation of the incident. No report had been released at the time of writing.
How do our grids compare and what can we learn?
Argentina has a higher level of synchronous generation and a lower level of renewables compared with Australia. It also has more interconnectors and a higher level of meshing than we do. Australia’s grid operates with much higher penetration of variable renewables.
The Australian Energy Market Operator (AEMO) has investigated major incidents across the world to learn from them, and no doubt will be doing the same in the case of Argentina.
Australia’s grid is rapidly transforming from relatively few large coal generators to more widely distributed and renewable energy sources.
Control schemes may need to be reviewed in light of an evolving, more dynamic grid.
Australia’s historical electricity demand is 33 per cent greater than Argentina’s and on a per capita basis, is 140 per cent higher.
Both countries rely on interconnection.
Though we may not know the final conclusions for some time, it’s likely a critical transmission failure resulted in 48 million customers in Argentina losing power.
