The Danish government’s vision for 2025 is to integrate 50% renewable energy into the power system. To this end, Energinet.dk has launched a project aimed at ensuring that the high degree of security of supply and the well-functioning market are maintained in step with the integration of 50% renewable energy into the power system. This is done by developing, testing and implementing a full-scale demonstration of a new intelligent monitoring and control concept for the Danish power system in a physical grid area.
The concept breaks new ground in that Energinet.dk is developing an intelligent monitoring system capable of collecting online measurements from all facilities such as 60/10 kV substations, local CHP plants and wind turbines. Online measurements provide a second-by-second snapshot of the operating conditions in the area and form the basis for making decisions on the required ancillary services that are to ensure continuous operational reliability and a well-functioning market.
As a brand new feature, Energinet.dk is developing and testing a system control unit, popularly called the 'cell controller'. Using intelligent automation, the cell controller can activate the distributed production units in the cell area and gather them in so-called virtual generators. The technology will enable the creation of new markets as the virtual generators can place bids in the existing markets and offer ancillary services such as reactive power control as well as voltage and frequency control. This is not possible today. Ultimately, the cell controller will be developed to a stage where it will be able to perform fully automatic controlled transition to island operation to prevent a blackout in the cell area and synchronisation back to normal parallel operation with the main power system, the operating situation permitting – all to the benefit of security of supply and the market.
The cell project is carried out in close collaboration with Syd Energi Net, and construction, testing and demonstration of a dedicated SmartGrid concept are done in Syd Energi Net's grid area. As such, several wind turbines, local CHP plants and electricity consumers are involved in the project. The vision for SmartGrid is to ensure a power system featuring optimum balance between environmental aspects, market services and security of supply – or renewable energy, price-sensitive demand and new technologies. The entire 60 kV and 10 kV distribution grid in Holsted, Southern Jutland, has been chosen as a test area and is considered a cell in this context – hence the project name: the Cell Project. The Cell Project also makes use of Syd Energi Net’s modern data communications network based on optical-fibre technology, which ensures safe and high-speed data transfer.
The monitoring and control system has already been established in two thirds of the Holsted area providing access to online operational measurements there. The first full-scale live test of the cell controller has now been carried out successfully in the power system near Billund and Hejnsvig. The monitoring system for the remaining Holsted area is planned to be set up in 2009, and the cell controller functionality will be developed and refined in parallel towards the second live test in 2010 and the third and final live test in 2011, which is planned to culminate with the entire Holsted area being in controlled island operation.
The just-ended live test has provided a great deal of new knowledge which will now be used in the further development of the cell controller, which, together with other current and new development initiatives, will form the framework of a new concept for controlling a power system featuring 50% renewable energy in 2025.
The major subcontractors in the project are Spirae Inc. on data communications and control systems, Energynautics G.m.b.H. on system stability simulation and Siemens A/S on power system stabilising units.