The invention relates to a method and a device for reducing the grounding impedance of a
transformer substation
grounding grid by additionally arranging a
capacitor module. The device comprises a plurality of
capacitor grounding devices, wherein each
capacitor grounding device comprises a plurality of capacitor units, an
epoxy resin cylinder, a damp-proof sealing ring, a connecting conductor and ametal disc; and the capacitor units are connected in series to operate, the capacitor units are wrapped by the
epoxy resin cylinders, the connecting conductors are used for connecting the capacitor units and penetrating through the
epoxy resin cylinders, sealing rubber pads are used at the joints of the connecting conductors and the upper ends and the lower ends of the epoxy resin cylinders, andthe
metal discs are used at the
tail ends of the capacitor grounding devices. According to the method and device, the
inductance component proportion of the grounding impedance of the
transformer substation
grounding grid is measured by using a grounding
impedance testing instrument, the specific
inductance value of the
transformer substation
grounding grid is obtained, then the number of the required capacitor grounding devices is obtained, after
simulation calculation
verification, the corresponding number of capacitor grounding devices are welded to the transformer substation grounding gridto reduce the
inductance component of the transformer substation grounding grid, and the effect of reducing the grounding impedance of the transformer substation grounding grid is achieved.