Assessment of the last-in-first out principle of access for managing the connection of distributed wind generators

Recent projects in the UK have investigated different connection arrangements for managing distributed wind generators to maintain thermal limits and a number of principle of access for generators to the limited distribution network capacity have been investigated. However, principle of access to manage voltage limits have not received as much attention. This study aims to evaluate the current practice for connecting ‘non-firm’ distributed wind generators under both voltage and thermal constraint conditions. It addresses the issue by developing a representative model of a UK 11 kV radial distribution feeder comprising a mix of urban and rural sections using time-step optimal power flow simulations. The results indicated that when the principle is applied under both network constraint conditions, it can lead to inefficient use of network capacities and reduced renewable energy yields.