Increasing renewable penetration on islanded networks through active network management : a case study from Shetland

The drive to reduce reliance on fossil fuel generation in meeting power system demand is encouraging network operators to develop novel methods of making greater use of available network capacity whilst maintaining stability and security. Challenges relating to network stability are particularly acute on islanded networks. The Northern Isles New Energy Solutions (NINES) project is implementing novel techniques for managing the power network on the Shetland Islands in the UK. Active Network Management is used to monitor and control the network and new wind generation in real time, and flexible demand is scheduled to minimise the use of conventional generation by reducing wind curtailment and minimising system losses. The flexible demand devices deployed also have the ability to respond to frequency therefore supporting system stability. This paper presents the development of two novel modelling techniques used in the design and deployment of NINES – an ‘envelope of stability wind generation’ and the use of Dynamic Optimal Power Flow to schedule flexible demand. A case study is presented which shows that an ANM scheme managing flexible demand has the potential to increase wind capacity connected on Shetland from the existing 4MW to 16.1MW. The management of domestic demand flexibility is shown to contribute up to 6.5GWh towards the reduction in conventional generation or up to 16.6GWh if domestic demand provides frequency response