The impact of network splitting on fault levels and other performance measures

The fault level rating of installed equipment in urban areas is a common restriction on the expansion of distributed generation (DG). One option for reducing fault level is to split the network at selected points by, for example, opening bus section circuit breakers that are normally run closed. This paper presents studies performed to evaluate the impact of network splitting on fault levels and various network performance measures such as reliability and power quality. Four generic test networks were used that reflect typical operating conditions and configurations of UK distribution networks, although the results are generally applicable to other networks. The studies provide valuable guidance on the potential benefits and costs of network splitting and so contribute to the debate on how to accommodate more DG on existing networks. Other issues like network operation and maintenance must also be considered when assessing if a particular network splitting option is acceptable from both a network and generation perspective.