An evaluation of dynamic thermal ratings for load accommodation in power distribution networks

Abstract

This thesis presents an evaluation of the use of Dynamic Thermal Ratings (DTRs) to provide additional network headroom for load consumer connections in electrical power distribution networks. The requirement for additional headroom can come from a number of sources including, limitations in the current network configuration, the need to provide connections to new consumers at minimal cost and to provide additional capacity in the transition to the low carbon economy. DTRs are a method by which the current carrying capacity of power system components such as transformers and overhead lines can be estimated in real-time through analysis of the surrounding meteorological conditions. The use of this technique has typically shown significant increases in available network capacity, however much of this work has considered such benefits in the context of increasing the capacity for wind generation connections. This research differs in its analysis of such benefits with regards to customer connection. Analysis of the present overhead line rating standards in the UK has shown that the system potentially over estimates the level of risk at which the network is operated. A set of adjusted ratings which meet these criteria are presented in this thesis. A generic, temperature sensitive load synthesis method is presented in order to estimate the benefits of DTRs within distribution networks. Through the use of such time-series load profiles the additional requirements of such an approach are exposed and analysed. Implementation of such a system has been shown to deliver additional network capacity for customer connections in both fit and forget and active network management scenarios.