The AEMC today commenced consultation on three rule change requests that relate to how electricity generators operate their equipment to help control the frequency in the power system. 

Stable frequency is an important part of maintaining a secure power system. Frequency varies whenever electricity supply does not exactly match consumer demand and uncontrolled changes in frequency can cause blackouts.

Chief amongst the proposed changes is the introduction of a mandatory obligation for all registered generators in the national electricity market to help to control power system frequency. Further proposed changes would see the removal of incentives which may have caused generators to become less responsive to frequency over time. 

Two of the rule change requests were submitted by AEMO, and the other by Dr Peter Sokolowski, a power systems academic from RMIT University.

Each of these rule change requests builds on previous work undertaken by AEMO and the AEMC. In particular, the AEMC’s Frequency control frameworks review, which concluded in July 2018, and AEMO’s incident report into the Queensland and South Australia system separation event on 25 August 2018, have both provided an important foundation for understanding and assessing the issues.

These reports found that, in recent years, the control of frequency in the power system has been deteriorating. This deterioration is mainly due to the detuning of the frequency responsiveness from existing synchronous generating plant. At the same time the increased connection of variable generating technologies makes the task of managing power system frequency following system disturbances more challenging.  

The final report of the AEMC’s Frequency control frameworks review highlighted several issues with the existing market and regulatory arrangements for frequency control, and included a collaborative work plan that set out a series of actions that would be progressed by the AEMC, AEMO and the AER to address issues related to frequency control in the national electricity market over the short, medium and long term. 

AEMO’s rule change requests are related to this work plan. In particular, the action that AEMO communicates whether there is a need to implement interim measures to address the deterioration in frequency performance before a longer-term mechanism for frequency control is implemented.

The Commission acknowledges the immediate need to improve frequency performance in the power system and sees the three rule change requests as an opportunity to improve power system security, which the AEMC has identified as one of the five key priority areas for reform in the national electricity market.

In determining a solution, the Commission will seek to address system security first and foremost. When the fundamental system security needs are met, the Commission will seek to investigate further improvements to the frequency control arrangements to increase the overall economic efficiency of frequency control in the national electricity market.

Submissions on the consultation paper are due by 31 October 2019.

This work is part of the AEMC's system security and reliability action plan.

Media: Prudence Anderson, Communication Director, 0404 821 935 or (02) 8296 7817