| In this dissertation work, a dynamic model that computes with reasonable accuracy the pollution flashover voltages of insulators energized with dc voltage is developed. Obenaus' basic concept was adopted for this purpose. The salient feature of this model is its capability to handle the actual geometry of practical insulators, contrary to majority of the previous models where only strips of electrolytes were used. The model is validated for its accuracy against independent researchers' data and a good correlation has been obtained.; The model is used to study the various behaviors of the insulators, such as the diameter effect, and the profile's effect. The order of merit of a number of insulators in line with the experimental results have been found. This is done by selecting a common base, such as mm/kV (leakage length per unit flashover voltage) or kV/m (flashover voltage per unit string length). For this purpose, a variety of insulators, such as suspension, station post, long rod and pin type were considered. Given the insulator type and the system voltage, the model can also predict the pollution severity up to which it can be safely operated. The model is capable of performing the equivalent flat plate model of actual insulators too to accuracy of {dollar}-{dollar}10%. The model is refined to reflect the field conditions by accounting for the various types of nonuniform distribution of the pollutants. Both single and strings of insulator were considered for this purpose.; The ultimate goal of this work is the day-to-day application of this model in the transmission design of both lines and converter stations. Accordingly, the use of the model as a Design Tool to select type and number of insulators for transmission lines has been demonstrated. This was performed for both uniform and nonuniform pollution severities. Additionally, the model is also capable of reflecting the surface properties by means of the surface resistance. The model could also be extended to predict the ac flashover voltages by using the appropriate arc propagation criteria applicable for ac. (Abstract shortened by UMI.)... |
