A key raison d’être of a grid connected microgrid is to be able to ‘island’.
For example, a community may want to power itself from local generation and storage and use the grid for backup. Alternatively, the local resources could be used as backup in case of failure of the main grid.
Key issues are the technology underlying the islanding and for utilities, the ability of the microgrid to deliver in terms of power quality and reliability and the impact on the main grid.
Nice Smart Valley
One of the use cases investigated by French distribution system operator (DSO) Enedis in the Nice Grid project was microgrid islanding. This is now being developed further in the Nice Smart Valley demonstration, which is part of the EU supported InterFlex initiative to move the earlier findings towards industrialisation.
“Our aim in Nice Smart Valley is to make the islanding process more automated and also to involve customers,” explains project manager Thomas Drizard from Enedis.
“A major challenge is to take out the human intervention and to be able to island remotely from the central control room so that the concept becomes replicable.”
Drizard says the microgrids will be implemented on two islands, including one close to Cannes which is connected to the mainland with a 10kV cable that is at risk of damage from for example, a ship’s anchor.
“In this case the microgrid would need to be able to power the island until the connection is repaired.”
The technology partner in the project is power solution provider Socomec, which developed the microgrid control solution for Nice Grid.
“In Nice Grid we tested the technology and in Nice Smart Valley we are further developing it to demonstrate that it works on a larger scale and with additional functionalities,” says Socomec Infrastructure Marketing Manager, Nadège Clerc.
Drizard comments that a range of customers are on the islands including residential and others such as a monastery.
As part of the project, which runs from 2017 to 2019, customers will be supplied with solar PV as the local generation resource alongside battery storage.
“It is important that islanding is operated in an area that makes sense for the distribution grid,” Drizard concludes. “The grid is quite stable in France but there are still some interesting use cases and these are also applicable elsewhere.”