TC 122 - UHV AC transmission systems
Standardization in the field of AC transmission technology for highest voltage of the system exceeding 800 kV, particularly the preparation of systems-oriented specifications such as those for planning, design, technical requirements, construction, commissioning, reliability, availability, operation and maintenance. Development of processes for specifying requirements and demonstrating whether the required performance of UHV systems is assured. Responsibility for equipment standards remains with product TCs, except for specific equipment which is not within the scope of an existing TC but is nevertheless essential for the UHV transmission system. The UHV AC Transmission TC will consult and coordinate with the product TCs in all systems-related aspects of equipment standards.
Système de transport UHT en courant alternatif
Normalisation dans le domaine du transport en courant alternatif ultra-haute tension (UHT) au-delà de 800 kV, en particulier élaboration des spécifications sur les aspects système tels que la planification, la conception, les exigences techniques, la construction, la mise en service, la fiabilité, la disponibilité, ainsi que l’exploitation et la maintenance. Ce comité développe des processus pour spécifier les exigences et démontrer que les performances requises pour les systèmes ultra-haute tension (UHT) sont assurées. Les Comités « Produits » gardent la responsabilité de l'établissement des normes d’équipement, à l’exception de celles qui concernent les équipements spécifiques qui ne relèvent pas du domaine d’un Comité existant mais qui sont néanmoins essentiels pour les systèmes de transport UHT. Le Comité en charge des systèmes de transport UHT en courant alternatif consultera et travaillera en coordination avec les Comités « Produits » pour tous les aspects système des normes d’équipement.
General Information
IEC TS 63042-301:2026, which is a technical specification, applies to on-site acceptance tests of electrical equipment with the highest voltages of AC transmission system exceeding 800 kV and its protection and control system.
The electrical equipment exceeding 800 kV includes the following items:
- power transformers;
- circuit-breakers;
- gas insulated switchgear (GIS);
- gas insulated transmission line (GIL);
- surge arresters;
- voltage and current transformers;
- shunt reactors;
- series compensators;
- insulators;
- disconnectors and earthing switches;
- high-speed earthing switches (HSES).
This second edition cancels and replaces the first edition published in 2018. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous edition:
a) new subclause with measurement of short-circuit impedance and load loss for on-site assembly transformer has been added;
b) new subclause with measurement of no-load loss and current for on-site assembly transformer has been added;
c) on-site acceptance test requirement for GIL has been added;
d) new clause with protection and control system on-site acceptance tests has been added.
- Technical specification34 pagesEnglish languagesale 15% off
- Technical specification71 pagesEnglish languagesale 15% off
IEC TS 63042-401:2026, which is a Technical Specification, gives guidance on UHV AC substation maintenance considering system-oriented maintenance issues of UHV AC transmission systems.
It is based on the development and on-site practice of maintenance technology involved in UHV AC transmission systems. It applies to power system planners, equipment suppliers, engineering contractors, maintenance staff and power grid operators.
- Technical specification45 pagesEnglish languagesale 15% off
IEC TS 63042-103:2025, which is a Technical Specification, specifies the basic security and stability requirements for UHV AC transmission systems in planning and design, the security and stability criteria, and security and stability analysis method for the UHV AC transmission systems.
This document is applicable to power grids of UHV AC systems and their associated equipment and connected systems.
- Technical specification26 pagesEnglish languagesale 15% off
IEC TS 63042-202:2021(E) provides common rules for the design of overhead transmission lines with the highest voltages of AC transmission systems exceeding 800 kV, so as to provide safety and proper functioning for the intended use.
This technical specification aims to give the main principles for the design of UHV AC overhead transmission lines, mainly including selection of clearance, insulation coordination and insulator strings design, bundle-conductor selection, earth wire/optical ground wires selection, tower and foundation design, environmental consideration. The design criteria apply to new construction, reconstruction and expansion of UHV AC overhead transmission line.
- Technical specification110 pagesEnglish languagesale 15% off
IEC TS 63042-302:2021(E) applies to the commissioning of UHV AC transmission systems.
It mainly specifies the test purposes, test items, test preconditions, test methods and test acceptance criteria during pre-commissioning and system commissioning. Also, the measurement requirements for system commissioning are specified.
- Technical specification56 pagesEnglish languagesale 15% off
IEC TS 63042-102:2021(E) specifies the procedure to plan and design UHV transmission projects and the items to be considered.
The objective of UHV AC power system planning and design is to achieve both economic efficiency and high reliability, considering its impact on EHV systems.
- Technical specification67 pagesEnglish languagesale 15% off
IEC TR 63042-303:2021(E) specifies measurement methods of UHV AC transmission line power frequency parameters. These measured parameters mainly include sequence parameters, mutual parameters between double-circuit lines, phase parameters and some other related parameters.
- Technical report35 pagesEnglish languagesale 15% off
IEC TS 63042-101:2019(E) specifies reactive power compensation design, voltage regulation and control, and insulation design for the coordination of UHV AC transmission systems.
- Technical specification30 pagesEnglish languagesale 15% off
IEC TS 63042-201:2018(E), which is a Technical Specification, provides common rules for the design of substations with the highest voltages of AC transmission systems exceeding 800 kV, so as to provide safety and proper functioning for the intended use.
- Technical specification60 pagesEnglish languagesale 15% off
IEC TS 63042-301:2018(E) applies to on-site acceptance tests of electrical equipment with the highest voltages of AC transmission system exceeding 800 kV.
- Technical specification34 pagesEnglish languagesale 15% off
IEC TR 63042-100:2016(E), 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.
- Technical report28 pagesEnglish languagesale 15% off
Frequently Asked Questions
TC 122 is a Technical Committee within the International Electrotechnical Commission (IEC). It is named "UHV AC transmission systems" and is responsible for: Standardization in the field of AC transmission technology for highest voltage of the system exceeding 800 kV, particularly the preparation of systems-oriented specifications such as those for planning, design, technical requirements, construction, commissioning, reliability, availability, operation and maintenance. Development of processes for specifying requirements and demonstrating whether the required performance of UHV systems is assured. Responsibility for equipment standards remains with product TCs, except for specific equipment which is not within the scope of an existing TC but is nevertheless essential for the UHV transmission system. The UHV AC Transmission TC will consult and coordinate with the product TCs in all systems-related aspects of equipment standards. This committee has published 11 standards.
TC 122 develops IEC standards in the area of Information technology. The scope of work includes: Standardization in the field of AC transmission technology for highest voltage of the system exceeding 800 kV, particularly the preparation of systems-oriented specifications such as those for planning, design, technical requirements, construction, commissioning, reliability, availability, operation and maintenance. Development of processes for specifying requirements and demonstrating whether the required performance of UHV systems is assured. Responsibility for equipment standards remains with product TCs, except for specific equipment which is not within the scope of an existing TC but is nevertheless essential for the UHV transmission system. The UHV AC Transmission TC will consult and coordinate with the product TCs in all systems-related aspects of equipment standards. Currently, there are 11 published standards from this technical committee.
The International Electrotechnical Commission (IEC) is the world's leading organization for the preparation and publication of international standards for electrical, electronic, and related technologies. Founded in 1906, the IEC provides a global platform for companies, industries, and governments to meet, discuss, and develop the international standards they require.
A Technical Committee (TC) in IEC is a group of experts responsible for developing international standards in a specific technical area. TCs are composed of national member body delegates and work through consensus to create standards that meet global industry needs. Each TC may have subcommittees (SCs) and working groups (WGs) for specialized topics.