Simulation Research On New Electro - Compensated Electrode Based On Ansoft Maxwell 's Calculation Capacitance

To establish one new vertical calculable cross capacitor standard with movable and fixed guard electrodes is one of the hottest issues in current international metrological research. It can combine the quantized hall resistance standard together for measuring the fine structure constant more accurately. In the meantime, it is not only the unique standard apparatus at the level of a few parts in one hundred million but also the traceability source of ac impedance system including capacitors, inductors and ac resistors. This paper is focused on the key technology problems of novel national calculable cross capacitor. The theoretical analysis about the generation mechanism of the end effect error, which is the maximum uncertainty source, will be carried on. The simulation of the two-dimensional electrical field distribution inside this capacitor by adopting our unique electrical auxiliary electrode instead of international common modified cone-end spike for compensating the end effect error should be also undertaken with electromagnetic finite element analysis software(Ansoft Maxwell),and the effect of a variety of installation errors on the value of cross capacitance. On basis of the simulation results, the optimum design of electrical auxiliary electrode can be manufactured. One side of the new electrical compensation electrode mainly include a electrode shell with 38 ° taper type transition surface electrode shell,a auxiliary electrode, a PTFE isolating spacer,a internal plane mirror. The optimal compensation voltage of the auxiliary electrode should be negative. To different size of the end of the new electrical compensation electrode, the optimal compensation voltage is different. To get the specific voltage value, it needs the further measurement by using the actual model. At the same time, the paper gives the explanation of the measurement and analysis method of the experimental data when explore new electric compensation electrode structure by using the actual model of calculable cross capacitor.