The use of 11 kV distance protection to increase generation connected to the distribution network

Targets introduced by the UK government state that by 2010, 10% of the total UK electrical energy should be supplied from renewable sources, in addition to the 10 GWe of combined heat and power (CHP). These targets will lead to the increased connection of distributed generation (DG) to the distribution network. This increase will eventually cause problems with existing protection schemes. To maintain the achieved and desired growth of DG capacity, a new approach to the protection of 11 kV circuits needs to be considered. A new type of scheme based on distance protection is described in this paper. Results are presented indicating the performance of the new scheme when subjected to DG current infeed.