Research on Pressure Control Material Based on Granular System in Current Transfer

TiB2 granules have the characteristics of high hardness, small volume resistance and not easy to be oxidized. As a pressure control material, its contact resistance will change significantly under the external pressure. It can be applied in the field of current transfer due to its fast change in resistance, including transfer current limiting and DC transfer breaking. In this paper, the pressure-resistance characteristics of the pressure control material are measured, and the relationship between pressure and resistance is obtained and fitted into a function. Then, a mathematical model of the pressure control material is established in the PSCAD, and the model is series connected with a vacuum interrupter to form a current transfer module. The module is connected in parallel with the current limiting reactor to form a new type of fault current limiter and connected in parallel with the IGBT module to form a DC circuit breaker. The current transfer during the resistance change is studied. The simulation results show that the current can be quickly transferred within a few milliseconds. During the current transfer, overvoltage will generate. Therefore, overvoltage protection and timing control need to be considered.