Model Study of HVDC Electric-Field Effects. Final Report

摘要

Energized scale models of HVDC transmission lines and converter stations can be used as design tools to determine the electric field distribution in their vicinity. To prove the method, an energized scale model of a +-400-kV HVDC test line and that of the Arrowhead +-250-kV converter station have been designed and built in order to compare the electric field distribution of the full-scale facilities with that of the models. Linear scale factors were 1/50 for the line and 1/33.33 for the station. The report reviews instrumentation, modeling and scaling problems and their solutions, calibration and verification tests, and discusses the accuracy of the model measurements. Comparison of corresponding ground level electric field strength test ranges shows that the agreement between full-scale and model measurements is good. Techniques were developed for full-scale and model conductor tests in laboratories, and for field and model experiments. An experimental method (the method of images) for determining the corona onset voltage of actual bipolar HVDC transmission lines with single conductors was developed. Additional experiments were conducted in various areas of the model converter station in various modes. Features studied were: electric field and ion current profiles under energized (in bipolar and unipolar modes) and partially deenergized conditions, effects of ground wires, effects of shielding, measurements on the end wall of the converter building. The feasibility of worst case open-circuit voltage and short-circuit current measurements on model objects and vehicles, and that of the measurement of the distortion of the electric field due to the presence of model vehicles was demonstrated. (ERA citation 06:020180)