IEEE C37.122-2010 IEEE Standard for High Voltage Gas-Insulated Substations Rated Above 52 kV.
5.1 Requirements for liquid in switchgear Subclause 5.1 of IEEE Std C37.100.1-2007 applies. 5.2 Requirements for gases in switchgear Subclause 5.2 of IEEE Std C37.100.1-2007 applies with the following addition: For compliance with local regulations, refer to 5.20.4 of this standard. 5.3 Grounding and bonding of switchgear Subclause 5.3 of IEEE Std C37.100.1-2007 applies with the following additions: 5.3.1 Grounding of enclosures The metallic enclosure shall be equipped with ground pads providing for connections to the ground grid, sized for the short-circuit current at each location which corresponds to the current specified for the installation. The ground pad shall conform to a hole pattern in accordance with ANSI/NEMA CC 1. All metal parts that do not belong to a main or auxiliary circuit shall be grounded. For the interconnection of enclosures, frames, etc., bolting or welding is acceptable to provide electrical continuity. Connections shall meet the requirements of IEEE Std 80 and IEEE Std 367. The continuity of the grounding circuits shall be assured, taking into account the thermal and electrical stresses caused by the current they may carry. The grounding system shall prevent step and touch voltages exceeding the limits defined in IEEE Std 80. 5.3.2 Grounding of high-voltage circuit All high-voltage parts where access is required or provided shall be capable of being grounded during maintenance. 5.3.3 Bonding of enclosures The various sections of the enclosure shall be electrically connected (bonded) together to provide a continuous current path through the entire length. Single-phase enclosures require bonding interconnections installed between the three-phase enclosures to provide a path for longitudinal continuous currents induced in the enclosures. Each of these bonding interconnections shall be connected to the ground grid as directly as possible by conductors capable of carrying the rated short-circuit current and the portion of the continuous current that flows into the ground.
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