Corona performance of a compact 230-kV line

Permitting requirements and the acquisition of new rights-of-way for transmission facilities has become increasingly difficult for most utilities, including Puget Sound Power and Light Company. In order to maintain a high degree of reliability of service while being responsive to public concerns regarding the siting of high voltage (HV) transmission facilities, Puget Power has found it necessary to more heavily rely upon the use of compact lines in franchise corridors. Compaction does, however, precipitate increased levels of audible noise (AN) and radio and TV interference (RI and TVI) due to corona on the conductors and insulator assemblies. Puget Power relies upon the Bonneville Power Administration (BPA) Corona and Field Effects computer program to calculate AN and RI for new lines. Since there was some question of the program´s ability to accurately represent quiet 230 kV compact designs, a joint project was undertaken with BPA to verify the program´s algorithms. Long-term measurements made on an operating Puget Power 230 kV compact line confirmed the accuracy of BPA´s AN model; however, the RI measurements were much lower than predicted by the BPA and other programs. This paper also describes how the BPA computer program can be used to calculate the voltage needed to expose insulator assemblies to the correct electric field in single test setups in HV laboratories