| The desire to maximize the power transfer on power utility right-of-ways has led to changes in transmission line design. One result is the "Compact" transmission line. While compact transmission lines maximize power transfer in the corridor, an undesirable effect is that insulators and hardware (e.g., conductor clamps, tangents and deadends) used on these lines are subjected to higher surface electric fields than on conventionally designed lines. These higher fields result in enhanced corona effects including electromagnetic interference, audible noise and the material deterioration of composite insulators.; Current design practice is to retrofit problem areas on these lines after installation has been accomplished. It would be better if hardware for compact lines were adequately designed prior to installation. To do this it is necessary to predict conditions for which corona streamers are initiated, and to develop a design strategy based on these conditions. To investigate this process, two electrodes were designed, one using an electric field optimization technique and the second, using a corona onset criterion, with the additional constraint that the volume of material in each electrode must be the same. The electrodes were manufactured from Oxygen Free High Conductivity (OFHC) copper, and analyzed to predict the corona performance of each.; The electrodes were then tested in the Washington State University high voltage laboratory and the results compared with the predicted values. The measured results compared favorably with the predicted values. The results show that it is possible to design high voltage hardware using a criterion other than an electric field criterion, and to achieve a measurable improvement in the corona voltage for the electrode. These techniques can then be applied to the design of hardware for compact transmission lines. |
