Consultation starts on expedited rule change to increase transparency of system restart plans

09 January 2018

The AEMC has released a consultation paper on a proposed rule change to clarify how AEMO shares information about system restart plans with generators, networks and other key parties involved in restoring the electricity system after a widespread blackout.  

AEMO is responsible for maintaining power system security. Following a large-scale blackout AEMO coordinates the restart and restoration process, using emergency procedures set out in a system restart plan.

Under the National Electricity Rules a system restart plan is classified as confidential information. AEMO proposes amending the rules to give it express authority to share and discuss system restart plans with relevant parties including generators contracted to provide system restart services, network businesses and jurisdictional system security coordinators.

As the AEMC considers this to be a non-controversial rule change proposal, we are proceeding under an expedited process, with a final rule due in February 2018.

Subject to any objections to the expedited process, there will only be one round of consultation. Objections to the use of the expedited process must be lodged by 23 January 2018.

Submissions on the rule change request are due by 6 February 2018.

Media: Bronwyn Rosser, Communications Specialist, 0423 280 341 or (02) 8296 7847.

Background

What happens in a system black event?

A large-scale blackout of the power system is called a system black event. These events are extremely rare.

System black events can occur when a sudden, unexpected loss of a major source of supply causes very rapid changes in system frequency which undermines the security of the electrical system. Generators and networks automatically disconnect or ‘trip’ when there is a very rapid change in frequency in order to protect equipment and personnel from harm.

If supply from the system is lost, most generators are not capable of independently restarting if they have tripped off. They need power from the grid to start running again.

How is the system restarted?

Restart services put energy back into the grid after a power outage so generators can start producing electricity again. Some generators have specialised equipment that allows them to restart without an external ‘kick start‘. These generators provide what are called system restart ancillary services. AEMO contracts system restart ancillary services from generators throughout the power system.

Following a system black event AEMO coordinates the restart and restoration process:

  • Transmission network companies work with AEMO to establish network paths to generators.
  • Transmission network companies work with the distribution network providers to prepare blocks of load to be reconnected progressively.
  • Distribution network providers prepare local networks to have power restored and coordinate reconnection with the transmission business.
  • AEMO and the transmission and distribution network companies must coordinate the restoration process with each state’s system security coordinator. These are known as jurisdictional system security coordinators.