Interconnection & Demonstration

1301_ODonnell_T_0017a-web

Interconnection & Demonstration
Examining interconnection technologies and characteristics which may play a crucial role in realising ambitious targets for renewable energy which is by its nature locally uncertain and variable.

Strand Lead: Dr Terence O’Donnell

Renewable energy is by its nature locally intermittent and variable, which gives rise to considerable challenges for its large scale integration into existing power systems. However this local variability could be off-set by ensuring that local deficits in energy are made up for by importing energy from remote locations where there is currently an excess. This idea has led to the concept of what is referred to as the “European Supergrid” , i.e. an electricity transmission system which would cater for the transmission of large quantities of power from one end of the continent to another or for example from remote offshore locations to load centres. In this way the problems associated with the variability of renewable energy can be mitigated by widespread geographical integration. Most scenarios which envisage a low carbon, high renewable content power system, recognise that fact that grid interconnection between different regions has an important role to play in the realisation of ambitious renewable energy targets. Establishing the feasible extent of such interconnection or super grid involves the investigation of technical, economic and social issues.

This strand is concerned with investigating some of the technical issues around the implementation of such interconnection. The research questions revolve around the topology, control and technology for such a grid. For example High Voltage Direct Current (HVDC) transmission is emerging as one of the preferred approaches to implementing such interconnection and this raises many questions regarding how mixed AC-DC system would be structured, operated and controlled and how they would interact. The integration of offshore wind energy is also an important element in achieving renewable energy targets, so that a significant portion of any future interconnection will be offshore. The strand is therefore also concerned with questions concerning the interconnection of offshore wind farms.

One of the key enabling technologies is Power Electronics. At the heart of any such grid are the power electronics based converters which convert AC to DC, DC to AC and perhaps DC-DC. The transient response, control strategies and interactions of these converters with the grid is a critical area for investigation. The activities of the strand have therefore got a particular focus on power electronics and control issues.

Future demonstration activities will be supported by the development of a real time digital simulation with hardware in the loop capability. This system allows a real time, computer based simulation of portions of the grid, to be interfaced with actual equipment (e.g. relays, controllers, power electronics, etc), so that the interaction between the equipment and grid can be studied in real time. This equipment can be used to develop, test and validate new control techniques or new equipment on a simulated grid before any such techniques would be deployed in a real situation.