The AEMC today made 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 the Australian Energy Market Operator and network businesses keep the lights on. This can include having the technical capability to control their voltage and frequency, and the ability to stay connected even when there is a major disturbance to the power system.
A large number of new generators like wind and solar farms are set to connect to the grid in coming years. Today’s new rules provide a flexible approach to setting the required technical standards so these new generators can join the power system at the lowest possible cost while maintaining system security.
Under the new rules, a connecting generator’s technical requirements are matched to local power system needs rather than a one-size-fits-all approach. This is key to keeping costs down for consumers.
This targeted approach will enable the standards to be negotiated for each connection – tailored to local circumstances. For example, if provision of voltage control is not an issue in a particular area because there are plenty of generators already providing this capability, then new generators connecting to that part of the system will not have to pay for unnecessary voltage control capability.
The new rules also tighten some standards where needed and set clearer roles and responsibilities so all parties – generators, networks and AEMO – know what they have to do when negotiating the required standards for a particular region.
This major piece of work is the result of a rule change request from AEMO and months of cross-industry collaboration. A team of technical experts comprising AEMO, generators, network businesses and power systems engineers worked with the AEMC throughout the project to systematically review each technical standard.
The new rules start on 5 October 2018, except for those generators which have already started the connection application process. For these generators, the rules include transitional arrangements to finalise their access standards with networks and AEMO by 1 February 2019.
These new rules for generator technical performance standards build 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 the AEMC’s other recent system security rules, these changes enable AEMO to keep the system secure in a lower-cost, more efficient way, rather than having to use ‘last resort’ constraint powers. We are working with AEMO and other stakeholders to evolve the frameworks where problems and areas for improvement are identified.
This rule change addresses a key recommendation from the Finkel review to update generator connection standards in the National Electricity Rules. It also marks the completion of all of the security-related recommended actions in the Finkel review that the AEMC is responsible for.
AEMC system security and reliability action plan
The AEMC has a system security and reliability action plan to provide AEMO with the tools it needs to manage a power system with a growing share of renewables and other forms of capacity. This includes new rules which started in July 2018 to make networks maintain minimum levels of system strength and inertia.
Media: Bronwyn Rosser, Communication Specialist, 0423 280 341; firstname.lastname@example.org
EXPLAINER OF TECHNICAL TERMS
How are reliability and security managed in the national electricity market?
To keep the lights on, the power system needs to be:
- secure – able to operate within defined technical limits, even if there is an incident such as the loss of a major transmission line or large generator
- reliable – have enough generation capacity, network capacity and demand response to supply customers.
The Australian Energy Market Operator (AEMO) is responsible for operating the power system in a secure and reliable state in accordance with standards and guidelines, including those set by the AEMC’s Reliability Panel.
What is a secure power system?
The power system is in a secure and safe operating state if it is capable of withstanding the failure of a single network element or generating unit.
Security events are caused by sudden equipment failure (often associated with extreme weather or bushfires) that results in the system operating outside of defined technical limits, such as voltage and frequency.
What is a reliable power system?
A reliable power system has sufficient generation and network capacity to meet the consumer load in that region.
Reliability events are caused by insufficient generation or network capacity to meet consumer load.
Reliability events due to insufficient generation and interconnector capacity are usually predicted ahead of time by supply and demand forecasting. The associated consumer load shedding may be shared across parts of the national electricity market.
What is power system inertia?
The ability of the system to resist changes in frequency is determined by the inertia of the power system. Inertia is provided as a consequence of having spinning generators, motors and other devices that are synchronised to the frequency of the system. Historically, in the national electricity market, plentiful inertia has been provided by synchronous generators, such as coal and gas-fired power stations and hydro plant.
However, some new generation technologies, such as wind turbines and solar photo-voltaic panels, are not synchronised to the grid and have low or no physical inertia, and are therefore currently limited in their ability to dampen rapid changes in frequency.
What is system strength?
Non-synchronous generators do not contribute to system strength as much as synchronous generating units. System strength is a measure of the current that would flow into a fault at a given point in the power system.
Reduced system strength in certain areas of the network may mean that generators are no longer able to meet technical standards and may be unable to remain connected to the power system at certain times.