Gas insulated apparatus

A gas insulated apparatus comprising:

• a grounded metal tank in which an insulating gas is enclosed;
• a conductor disposed in the grounded metal tank, a voltage being applied to the conductor;
• and
• a non-linear resistance layer disposed on at least part of an inner surface of the grounded metal tank and made from an insulating material containing a plurality of particles of a single non-linear resistance material, the insulating material being a single material arranged in a single layer, the non-linear resistance layer comprises:
• a first portion immediately under a metal foreign object and containing an entirety of at least one of the particles, the first portion configured to become a conductive portion when a voltage higher than or equal to a threshold is applied to the metal foreign object, the metal foreign object contacting the insulating material,
• a second portion, formed between the grounded metal tank and the first portion of the non-linear resistance layer and under the metal foreign object, the second portion contains an entirety of at least another one of the particles, the second portion configured to maintain insulation when the voltage higher than or equal to the threshold is applied to the metal foreign object,
• wherein the non-linear resistance layer has a total thickness that is larger than a sum of a thickness of the conductive portion of the first portion of the non-linear resistance layer and a diameter of the at least another one of the particles in the second portion of the non-linear resistance layer, and
• wherein the plurality of particles of the single non-linear resistance material directly contact the insulating material and the plurality of particles of the single non-linear resistance material are distributed in the insulating material, and there is no contact between the plurality of particles of the single non-linear resistance material and the metal foreign object.