Grid stability and resilience | Syncons+flywheels in SA grid
The South Australian grid operator, ElectraNet, which enjoys a large contribution from renewables on its system, is now benefitting from the operation of four synchronous condensers (plus flywheels). These should help it address shortfalls in system strength and inertia
Above: First synchronous condenser arrives at Davenport (Photo: GE)
ElectraNet, South Australia’s transmission system operator – which has to manage more than 50% renewables on its grid – now has four synchronous condensers in operation to help it, two at Robertstown, about 135 km northeast of Adelaide, and two at Davenport, near Port Augusta – the first such large scale machines to be installed on the South Australian network. The two synchronous condensers installed at Davenport have been designed and manufactured by GE, and those at Robertstown by Siemens Energy. All the synchronous condensers are equipped with flywheels. ElectraNet chief executive, Steve Masters, said the growth of renewables within the South Australian power network had created a shortfall in system strength and inertia which needed to be addressed to ensure electricity users continued to receive a secure and reliable power supply. “In the past, system strength has been provided
GE units Siemens units
by traditional power sources such as gas-fired units, but as more renewable energy enters the grid, traditional power sources operate less often, creating the shortfall. When there is a shortfall, the Australian Energy Market Operator (AEMO) directs generators to address it, which is costly and ultimately adds to a customer power bill.” In the 12 months up to October 2021, when the new synchronous condensers became operational, the cost of these directions had been about $34 million, he estimated, which is paid for by power customers. “With the synchronous condensers now in operation, costly AEMO directions can be avoided.”
Above: Flywheel on test bench, Mülheim (Photo: Siemens Energy)
Cooling system
Stator Exciter
A shortfall in system strength (which relates to the ability of a power system to manage minor fluctuations in supply or demand while maintaining stable voltage levels) was declared
by AEMO on 13 October 2017 and a shortfall in inertia (affecting the ability of the power system to manage fluctuations in supply or demand while maintaining stable system frequency) was declared on 24 December 2018.
In June 2019, ElectraNet applied for contingent project funding to the Australian Energy Regulator, after the AER endorsed ElectraNet’s economic assessment for the project in February 2019. While the overall project cost was estimated at $181.8 million, ElectraNet required a lesser amount of $166 million, as the project would allow the TSO to defer or replace several other projects for which it had already received funding. This was approved by the Australian Energy Regulator in August 2019.
The overall project cost is currently put at about $190 million.
Rotor
Above: Core components of a GE synchronous condenser, without flywheel
Left hand picture: synchronous condenser in place at Robertstown, flywheel to the right and pony motor far right. Right hand picture: the two buildings in which the Robertstown synchronous condenser systems are housed (Photos: Siemens Energy)
22 | January/February 2022|
www.modernpowersystems.com
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