Real-time thermal rating and active control improved distribution network utilisation

This paper describes work carried out in the UK as part of a collaborative project including Parsons Brinckerhoff, Durham University, Scottish Power Energy Networks (SPEN), ALSTOM Grid and Imass, part-sponsored by the UK Government´s Technology Strategy Board (TSB ). The aim of the project is to evaluate the extra thermal capacity available in the critical network components, overhead lines, transformers and cables when the thermal limits are varied many times a day according to the prevailing environmental conditions. This Dynamic Thermal Rating (DTR) technique could enable generators to enhance their energy export or defer network reinforcement. In 2009 prototype protection relays were installed on SPEN´s network to calculate the dynamic thermal rating for an overhead line, transformer and underground cable. The paper includes an analysis of the field data gathered from site which is used to verify the accuracy and benefits of the real time thermal ratings.