Answering questions that may arise related to the meaning of portions of an IEEE standard concerning specific applications.

IEEE Standards Interpretation for ANSI C57.12.10™-1997 Standard Requirements for Liquid-Immersed Power Transformers

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January 2005

Interpretation Request #1
Clauses: 5.5, 5.5.1, 5.5.2, and 5.5.3

Clause 5.5 Ground Pads. Does part of this section refer to the ground pads on the lower exterior walls of the transformer tank and another part refer specifically to ground pads on the top of the tank? Or does 5.5.1 refer to pads on the exterior walls of the tank, and 5.5.2 and 5.5.3 refer to pads on top of the tank?

Interpretation Response
Clause 5.5 of the IEEE Std C57.12.10-1997 defines the specific construction, location, and quantity of tank ground pads. Clause 5.5.1 describes how the pad shall be constructed and attached to the tank. Clause 5.5.2 describes the quantity and location of the pad for transformers 2500 kVA and smaller, while clause 5.5.3 does the same for the two pads required for transformers larger than 2500 kVA. These pads shall be located near the base, per clause 5.5.1. All other ground pads are specified by the user. For example, ground pads for surge arresters can be specified by the user per clause 9.12 or per the user's own requirements.