The AEMC has made a rule that makes significant changes to technical performance standards for generators seeking to connect to the national electricity grid, and the process for negotiating those standards. 

Generators play an important role in helping AEMO and network businesses keep the power system secure. This can include having the technical capability to help control power system voltage and frequency, and the ability to stay connected when there are major disturbances to the power system. 

The AEMC has made a rule that establishes a flexible approach to setting standards that enables targeted, least-cost ways of connecting new generators. The rule also amends a number of the standards themselves.

This rule builds on AEMO’s comprehensive toolkit to manage system security. For example, AEMO can already stop a generator from dispatching its power into the grid at any time if system security is at risk. However, along with other recent system security rules, these changes help AEMO keep the system secure in a lower-cost, more efficient way, rather than having to use ‘last resort’ constraint powers.

Final determination

On 27 September 2018 the AEMC  published a rule determination for this rule change request, including making a rule.

A changing energy mix is creating new challenges for keeping the power system in a secure state at the least cost to consumers. In particular, the ability to effectively control frequency and voltage on the power system is diminishing as synchronous generating systems exit the market and new asynchronous generating systems and distributed energy resources enter the market. 

To address these issues the rule improves and clarifies the negotiating process to agree levels of technical performance when connecting generators, customers and market network service providers. Under the rule, negotiations can occur more efficiently so that each connection has a level of performance that balances system security and cost based on the needs of the local system. 

The rule also changes the technical requirements for connecting generators, including the requirements for generating systems to be able to:

• control their active power output, to limit their contribution to frequency and voltage disturbances 
• supply and absorb reactive power for the control of voltage where this service is needed on the power system 
• inject and absorb reactive current during disturbances, and
• maintain operation in the face of certain frequency and voltage disturbances (including faults and contingency events).

Stakeholder technical working group

A technical working group comprising AEMO, generators, network businesses and power systems engineers worked with the AEMC throughout the project to systematically review each technical standard. The AEMC also held a stakeholder workshop on 26 June 2018 to enable a broader group of technical experts to provide their input on the draft rules.

Background

On 11 August 2017 AEMO submitted a rule change request seeking changes to the access standards for generating systems in the National Electricity Rules (NER). AEMO also requested changes to the negotiating framework that translates those access standards into the standard of performance required of the physical equipment that makes up and connects to the power system.

Due to the changing generation mix in the power system, AEMO considered that the current access standard settings in the NER and the negotiating framework to set performance standards are not adequate to ensure the ongoing security of an evolving power system.

To address these issues, AEMO proposed:

• amending or introducing a number of access standards for connecting generators, including those relating to voltage control and reactive power provision, disturbance ride through, system strength, active power control and remote monitoring and control
• amending the process for negotiating performance standards
• implementing transitional arrangements applying the changes to any performance standards agreed on or after 11 August 2017.

Assessment of this rule change request forms part of the AEMC’s broader package of system security work, which includes a range of measures to address a transforming power system with reduced inertia and system strength.

This rule change request also covers part of recommendation 2.1 made by the Finkel Panel in its review into the future security of the national electricity market to “review and update the connection standards in the NER in their entirety”. This rule change request relates to the connection standards for generators, and not for other equipment such as market network service providers and certain large customers. However, the changes to the negotiating process will affect all of these types of connections.