scope:

This standard sets performance requirements for liquid insulated distribution and power transformers, both naturally cooled and transformers utilizing forcibly circulated cooling medium. The standard limits Approval for the naturally cooled transformers rated from 5 to 10,000 kVA and 35 kV class or lower.

This standard applies to any component intended for use as a protective device and that is normally provided as part of the transformer assembly. Use of components previously Approved as individual protective devices shall not automatically result in an Approved transformer assembly.

Purpose

This standard states Approval requirements for transformers insulated with less or nonflammable liquids.

Approval criteria may include, but are not limited to, performance requirements, marking requirements, examination of manufacturing facilities, audit of quality assurance procedures, and a follow-up program.