Insulation spacer and gas insulation shutoff apparatus using the insulation spacer

An insulating spacer of a gas insulation shutoff apparatus including a grounded tank filled with an insulating gas, a high-voltage conductor provided within the grounded tank, and the insulating spacer supporting and fixing the high-voltage conductor within the grounded tank, the insulating spacer comprising:

• a conductor connected to the high-voltage conductor;
• an insulating structure supporting and fixing the conductor within the grounded tank;
• and
• a nonlinear resistance layer provided on a creepage surface of the insulating structure,
• wherein the nonlinear resistance layer is provided in a portion that is a high-field portion of the creepage surface of the insulating structure, a first end of the nonlinear resistance layer is in contact with the grounded tank, a gap, in which the nonlinear resistance layer is not provided on the creepage surface, is arranged between the conductor and a second end of the nonlinear resistance layer that is opposite to the first end, and the second end is uncovered,
• wherein the nonlinear resistance layer is provided so as to cover a motional range of a metal foreign substance on the creepage surface of the insulating structure, and
• wherein the motional range essentially includes a first range from a bottom surface of the grounded tank to a maximum flying height of the metal foreign substance, and includes a second range from the maximum flying height to a height causing no dielectric breakdown starting from an end of the nonlinear resistance layer,
• wherein the high-field portion has an electric field value of at least 70% of a maximum value of a creeping electric field of the insulating structure, and
• wherein the nonlinear resistance layer has a thickness of at least 20 μm and less than 5 mm.