Digital simulation of source-insulator interaction in HVDC pollution tests

A technique is presented for digital computer simulation of the interaction between a polluted insulator and a high-voltage, direct-current test source. Both uncontrolled and feedback-controlled voltage-double sources are considered. The polluted insulator is represented by one or more arcs in series with the wet conducting layer. The arc is represented by a simple dynamic equation, and an attempt is made in the model to account for thermal phenomena in the unbridged wet layer. The simulation technique is then used to investigate the effect of the DC source parameters on the error obtained in the insulator flashover voltage. Both the effects of maximum and mean dynamic voltage drops are studied. It is shown that the approach applies well for both controlled and uncontrolled sources, while the effect of an external damping resistor is treated separately. Wherever possible the simulation results are compared to experiments, and in view of the complexity of the problem, the agreement is satisfactory