ITEE Innovation Expo 2008 : Project Details

Electric field modelling of the 500 kV transmission line insulator

Background Powerlink Queensland is looking to introduce 500kV powerlines into the transmission network. These need to be tested to ensure they will not be produce excessively high electric fields, as this can cause unwanted effects such as corona. This can reduce the insulator lifetime and produce radio interference or audible noise. Also want to make sure the voltage rating of insulator disks is not exceeded. Easiest and cheapest way to do this is computer simulation. Scope This thesis uses the program COULOMB to model the various types of 500kV insulator structures (strain, suspension and vee-string) that Powerlink intend to use to ensure that the electric field at any point along the insulators does not reach excessively high levels. Results The electric fields produced are not excessively high in these strain insulators – however it would be nice if it were smaller to reduce the chance of corona occurring (such as in heavy rain). This could be achieved several ways: - Use multiple-string (twin, triple, quad) insulators rather than single string insulators. - Use a different corona ring. - Use a corona ring at the dead end.