1. Vaughan Roberts UK Session 4 – Block 4 Barcelona 12-15 May 2003 1 ACTIVE NETWORKS FOR THE ACCOMMODATION OF DISPERSED GENERATION

2. Vaughan Roberts UK Session 4 – Block 4 Barcelona 12-15 May 2003 2 The existing technical and regulatory structure of distribution networks is incapable of supporting this evolution Customers are used to having a “stiff” network but this tends to become too expensive Generation increases fault levels Security of supply requires different approach Voltage stability may become an issue What’s happening to the network ? Slowly but steadily “embedded” generators are starting to be added.

3. Vaughan Roberts UK Session 4 – Block 4 Barcelona 12-15 May 2003 3 The answer: a different concept of network operation message 1: The network of the future does not supply power; it supplies connectivity message 2: The “infinite network” as customers used to know it no longer exists

4. Vaughan Roberts UK Session 4 – Block 4 Barcelona 12-15 May 2003 4 Improve reliability by interconnection The network becomes a NETwork at last ! There is always more than one path Active management of “congestion” Prevent propagation of an overload by isolating the “sick” part of the network

5. Vaughan Roberts UK Session 4 – Block 4 Barcelona 12-15 May 2003 5 Network subdivided into cells acting as ‘independent’ islands (example) Transmission Network MV Cell HV Cell

6. Vaughan Roberts UK Session 4 – Block 4 Barcelona 12-15 May 2003 6 We’re not there yet: R&D agenda More dynamic reliability model Efficient planning requires a mature market for embedded generation. How to bridge the present immature phase ? Tools for voltage control Algorithms to (re-)configure networks automatically for optimal power flow and losses Concepts for protection Cost of system services to be quantified