This article was originally published on 20 December 2019 in Energy:2030 Issue 24.
The Australian Energy Market Commission (AEMC) issued its final report on 12 December following a black system event, setting out recommendations on measures to enhance the resilience of the power system.
On 28 September 2016, there was a black system event in which around 850,000 South Australia customers lost electricity supply. The event highlighted issues with the National Electricity Rules (NER) system security frameworks and the AEMC was commissioned to conduct a review on any systematic issues that contributed to the loss of power or affected the response to it.
Since the event, AEMC said there have been a number of reforms made to enhance resilience, including for improved system strength, inertia and emergency frequency control. The Australian Energy Market Operator (AEMO) has also updated and revised operational actions. Taking account of these reforms, the AEMC has identified operational approaches to enhancing power system resilience as an area where there are further opportunities for development, in particular in relation to “indistinct” events. These are the risks associated with distributed events that act on multiple generation and network assets in an affected area over time, rather than from the failure of a specific asset.
The AEMC has made recommendations for changes to the NER framework for power system security in three areas.
The first is the implementation of a general power system risk review. This will implement a holistic review process to identify emerging risks to the power system from all sources. It will act as the “front-end” risk identification process to inform risk management actions through other mechanisms. The review will be carried out on an annual basis and be integrated with existing planning frameworks. It will involve AEMO and the transmission and distribution network service providers.
The AEMC recommended introducing “protected operation” as a new operational tool for AEMO. This will allow it to adjust the settings of the power system during abnormal conditions, such as extreme weather, to account for the increased risk that the system could be impacted. It will also enable it to take additional actions such as constraining generator dispatch, limiting inter-connector flows or directing certain generators to run. Because operating in protected mode could come at significant cost to consumers, AEMO will consult on the nature of the indistinct events it will protect the system against, what actions it will take to do so and the triggers for those actions.
In addition to the pre-defined measures, “ad-hoc” protected operation would enable AEMO to take action necessary as an emergency measure, with public reporting after the fact.
The review also recommended clarifying that AEMO and market participants must continue to comply with the NER during a period of market suspension, except in accordance with specific provisions for flexibility. These would give AEMO flexibility to determine that compliance with a rule would create a material risk to its ability to maintain power system security during a period of spot market suspension. This provision would have arrangements for transparency included.
As well as the proposed measures, AEMO recommended a programme of future work. This should look at how to better account for non-credible contingencies in the network planning process, whether the existing system standards are fit for purpose or new standards are required, and if enhancements are needed to the frameworks for load shedding and system restoration.
The concept of a protected mode, while it gives the market operator more flexibility than it currently has to manage the system, still appears very prescribed by GB standards, where incentive arrangements play a key role.
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