Abstract: As a core international standard governing medium and high-voltage electrical equipment, IEC 62271-200:2021 “High-voltage switchgear and controlgear – Part 200: AC metal-enclosed switchgear and controlgear for rated voltages above 1 kV and up to and including 52 kV” has comprehensively upgraded the technical requirements for AC metal-enclosed switchgear and controlgear. This article elaborates on the scope of application, key technical revisions and practical guiding value of the standard, aiming to provide technical reference for engineers, manufacturers and relevant practitioners in the power industry to accurately grasp and implement the standard.

1. Introduction

AC metal-enclosed switchgear and controlgear are crucial components in power transmission and distribution systems, undertaking the functions of power distribution, control and protection. With the continuous development of the power industry and the increasing demand for power supply reliability and safety, the relevant technical standards are constantly being optimized and upgraded. Released in May 2021, IEC 62271-200:2021 is the third edition of this standard, which cancels and replaces the second edition (IEC 62271-200:2011) and constitutes a major technical revision. This revision not only aligns with the latest technical development trends of the industry but also further improves the safety, reliability and standardization of equipment, playing an important guiding role in the global power equipment manufacturing and application fields.

2. Scope of Application of IEC 62271-200:2021

IEC 62271-200:2021 is applicable to prefabricated AC metal-enclosed switchgear and controlgear assemblies, with clear limitations on the key parameters of the equipment. Specifically, the rated voltage of the applicable equipment is above 1 kV and up to and including 52 kV, the service frequency is up to and including 60 Hz, and it can be installed both indoors and outdoors. It should be noted that the assemblies covered by this standard can include air-insulated and/or fluid-filled compartments, which covers most of the common AC metal-enclosed switchgear types in the current power system. This clear scope of application helps to ensure the pertinence and effectiveness of the standard, avoiding ambiguity in the application process.

3. Key Technical Revisions of IEC 62271-200:2021

Compared with the 2011 edition, IEC 62271-200:2021 has made a series of significant technical revisions, involving clause numbering, definition supplements, test content adjustments, etc. The main key revisions are as follows:

3.1 Alignment with IEC 62271-1:2017 and Definition Supplements

To enhance the consistency and coherence of the entire IEC 62271 series of standards, the 2021 edition adjusts the clause numbering to align with IEC 62271-1:2017, including adopting the subclause names of clause 3. At the same time, in clause 3, specific definitions of “in service”, “normal operating condition” and “normal use” are added. These definitions further clarify the working state and application scenarios of the equipment, providing a clear basis for the design, testing and operation of the equipment, and avoiding misunderstandings caused by ambiguous terms in practical applications.

3.2 Adjustment of Internal Arc Testing Content

The internal arc testing content of pole-mounted switchgear is removed from this standard, as this part of the content is now covered by the specific standard IEC 62271-214:2019. This adjustment optimizes the content structure of the standard, making the division of labor between standards more reasonable and avoiding duplication of content. In addition, the 2021 edition also introduces a 1-second rule for criterion 4 during internal arc tests (IAC tests), which specifies the judgment criteria for ignition caused by hot gases and glowing particles, further improving the accuracy and strictness of internal arc testing. For switchgear with protrusions, the standard also gives a more precise description of internal arc tests in Annex A, providing detailed guidance for the testing of such special-structured equipment.

3.3 Improvement of Earthing Circuit Requirements

The 2021 edition provides a more precise description of the earthing circuit, including the addition of ratings and test requirements for the earthing circuit. The earthing system is an important part of ensuring the safety of electrical equipment and personnel. The improvement of these requirements helps to enhance the reliability of the earthing circuit, effectively preventing electric shock accidents caused by poor earthing and improving the overall safety performance of the equipment.

3.4 Optimization of Mechanical Tests and Main Circuit Resistance Measurement

In terms of type testing, the 2021 edition reduces the number of mechanical tests on interlocks and gives a more precise description of the forces applied during type testing (see clause 7.102). This optimization not only reduces the test burden of manufacturers on the premise of ensuring test effectiveness but also improves the accuracy and repeatability of the tests. In addition, regarding the resistance measurement of the main circuit, the 2021 edition stipulates that it is only necessary to measure before the continuous current test (as a reference for routine tests) and no longer needs to measure after the continuous current test. The reason for this revision is that the resistance value measured after the temperature rise test (which is part of the continuous current test) has no practical significance, and re-measurement will not provide new effective information.

3.5 Update of Normative References and Improvement of LSC Category Description

The 2021 edition updates the normative references, referring to a series of updated standards such as IEC 62271-100:2021, IEC 62271-103:2021, IEC 62271-105:2021 and IEC 62271-106:2021. At the same time, in clause 7.101.2, it also considers IEC 62271-107:2019 and IEC/IEEE 62271-37-013:2015, ensuring that the standard keeps pace with the latest technical achievements in the industry. In addition, the standard gives a more precise description of the Loss of Service Continuity (LSC) category and adds an explanatory flowchart in Annex D, which helps engineers and operators better understand and judge the service continuity level of the equipment, providing a basis for the rational selection and configuration of equipment in power systems.

4. Practical Application Significance of the Standard

The implementation of IEC 62271-200:2021 has important practical significance for the power industry. Firstly, in terms of safety, the standard further improves the requirements for internal arc testing, earthing circuits and other key safety links, which helps to reduce the risk of accidents such as electric arcs and electric shocks, and better protect the safety of operators and equipment. Secondly, in terms of reliability, the optimization of test requirements and the improvement of technical indicators help to improve the stability and durability of equipment, reduce the failure rate of equipment during operation, and ensure the reliable supply of power. Thirdly, in terms of standardization, the alignment of the standard with other related standards and the supplement and clarification of terms help to unify the technical requirements and test methods of global AC metal-enclosed switchgear, facilitating the international circulation of products and technical exchanges and cooperation. Finally, for manufacturers, the standard provides clear design and production guidelines, helping to optimize the product structure, improve production efficiency and enhance the market competitiveness of products.

As an important international standard in the field of AC metal-enclosed switchgear, IEC 62271-200:2021 has achieved comprehensive technical upgrades and optimizations compared with the previous edition. Its clear scope of application, scientific and reasonable technical requirements and detailed test guidelines provide important support for the healthy development of the global power industry. For relevant practitioners in the power industry, it is crucial to accurately grasp the core content and technical revisions of the standard, and effectively implement the standard in equipment design, manufacturing, testing and operation. In the future, with the continuous progress of power technology, it is believed that the standard will be further revised and improved to adapt to the new development needs of the industry.

References

[1] IEC. IEC 62271-200:2021 High-voltage switchgear and controlgear – Part 200: AC metal-enclosed switchgear and controlgear for rated voltages above 1 kV and up to and including 52 kV[S]. Geneva: International Electrotechnical Commission, 2021.

[2] NSAI. I.S. EN IEC 62271-200:2021 High-voltage switchgear and controlgear – Part 200: AC metal-enclosed switchgear and controlgear for rated voltages above 1 kV and up to and including 52 kV[S]. Dublin: National Standards Authority of Ireland, 2021.

[3] Payapress. IEC 62271-200: Internal Arc, LSC and Type Tests[EB/OL]. https://payapress.com/iec-62271-200-internal-arc-lsc-and-type-tests/, 2025.