A project has been initiated to improve the delivery of cable ratings calculations through the use of more flexible and accurate Finite Element Analysis (FEA) modelling methods. The project will demonstrate the advantages of finite element analysis of cable rating problems compared to the currently used finite difference method. Analyses performed by BICC (prior to their take over and closure) demonstrated the advantages of this method. FEA is the only readily available method for accurately modelling problems such as cable ratings and can be extended to include phenomena such as thermal dry out. The Auckland black-out demonstrated the need for utilities to understand and be able to model the ratings of their cable systems to avoid thermal runaway and consequent failures.
Rating methods employed in the design of both forced cooled and naturally ventilated cable tunnels. The objectives of this project are to: