This part of IEC 63042, which is a Technical Report, specifies the reference for the standards and guidelines for UHV AC transmission systems. This document provides an overview of these standards as well as guidelines. This document is developed to clarify standardization items and/or guideline items for UHV AC transmission systems. It describes the items to be considered for each stage of planning, design, construction, commissioning, operation, and maintenance during the development of IEC publications for UHV AC transmission systems. NOTE Based on this IEC/TR 63042-100, TC 122 will prepare the standards and guidelines for UHV AC transmission systems, but it is not limited by the framework of the TR. A systematic approach is necessary for the preparation of systems-oriented specifications such as those for planning, design, technical requirements, construction, commissioning, reliability, availability, operation, and maintenance.