Insulation Performance of Graphene Reinforced Copper Chromium Contact Material in a Vacuum Environment

Graphene reinforced copper matrix composite material (GR/Cu composite material) exhibits excellent physical and chemical properties and ablation resistance in SF6 circuit breakers, but has not yet been applied in vacuum circuit breakers. From the state-of-art, there is no research on dielectric properties of the vacuum gaps with GR/Cu electrodes. The objective of this study is to experimentally determine the electrical dielectric performance of a Gr-CuCr composite contact material in a vacuum interrupter (VI). The electrode material includes Cu60Cr40(GR-0wt%), Cu60Cr40(GR-1wt%), and Cu60Cr40 (GR¬3wt%). The contacts are mounted in the 24 kV commercial VIs, with the contact diameter set to 72 mm. Within the range of 1wt% to 3wt% graphene content, the power frequency breakdown voltage decreases as the graphene content increases. Compared to Cu60Cr40(GR-0wt%), Cu60Cr40 (GR1wt%) exhibits a reduction in power frequency breakdown voltage ranging from 5.9% to 21.6%. For Cu60Cr40 (GR-3wt%), the decrease in power frequency breakdown voltage is more pronounced, ranging from 17.6% to 21.6%. In terms of the 50% breakdown voltage across contact gap distances of 3-13mm, the order from highest to lowest is Cu60Cr40(GR-0wt%) > Cu60Cr40(GR-1wt%) > Cu60Cr40(GR-3wt%). These research findings offer valuable theoretical and technical insights to support the adoption of graphene reinforced copper matrix composite material in vacuum switches.