DIN EN IEC 62271-202:2024-03

This part of IEC 62271 specifies the service conditions, rated characteristics, general structural requirements and test methods of enclosed high-voltage prefabricated substations. These prefabricated substations are cable-connected to AC high-voltage networks with an operating voltage up to and including 52 kV and power frequencies up to and including 60 Hz. They can be manually operated from inside (walk-in type) or from outside (non-walk-in type). They are designed for outdoor installation at locations with public accessibility and where protection of personnel is provided. These prefabricated substations can be situated at ground level or partially or completely below ground level. The last are also called "underground prefabricated substations". In general, two types of prefabricated substations are considered in this document: - high-voltage switchgear prefabricated substations; - high-voltage/low-voltage transformer prefabricated substations (step-up and step-down). A high-voltage switchgear prefabricated substation comprises an enclosure containing in general the following electrical components: - high-voltage switchgear and controlgear; - auxiliary equipment and circuits. A high-voltage/low-voltage transformer prefabricated substation comprises an enclosure containing in general the following electrical components: - power transformer(s); - high-voltage and low-voltage switchgear and controlgear; - high-voltage and low-voltage interconnections; - auxiliary equipment and circuits. However, relevant provisions of this document are applicable to designs where not all these electrical components exist (for example, a prefabricated substation consisting of power transformer and low-voltage switchgear and controlgear). The listed electrical components of a high-voltage/low-voltage transformer prefabricated substation can be incorporated in the prefabricated substation either as separate components or as an assembly type CEADS according to IEC 62271-212. This document only covers types with natural ventilation. However, the relevant provisions of this document also apply to types with other forms of ventilation, with the exception of the rated power of the prefabricated station and the associated enclosure class, the continuous current tests and all heating-related requirements, for which an agreement between the manufacturer and the operator would be required. IEC 61936-1 contains general rules for the design and erection of high-voltage power installations. It also specifies additional requirements for external connections, erection and operation at the site of prefabricated high-voltage stations according to IEC 62271-202, which are considered to be part of such an installation. High-voltage stations that are not prefabricated are dealt with in IEC 61936-1 in a general form. Prefabricated stations with high-voltage switchgear and/or switching devices may contain instrument transformers in accordance with IEC 61869 (all parts). These stations are not prefabricated high-voltage/low-voltage transformer substations. The standard differs from DIN EN 62271-202 (VDE 0671-202):2015-02 as follows: a) the content and structure of the entire document have been revised in line with IEC 62271-1:2017; b) the title and scope have been modified to include prefabricated stations containing high-voltage switchgear and/or controlgear; c) CEADS have been included as a possible component of a medium-voltage/low-voltage prefabricated station; d) 7.2.101 now takes into account the possible effects of elements in the environment on the dielectric strength of high-voltage components such as high-voltage switchgear and/or switching devices or high-voltage connections with a non-metallic housing or without a grounded shield; e) A new informative Annex G has been added with a test procedure for evaluating the effects of solar radiation on temperatures inside the enclosure, together with instructions for its application; f) a new informative Annex H has been added for the appropriate consideration of the installation conditions of electronic devices; g) the rated power of a prefabricated station is now defined as a rated value with three parameters. See 5.101.1; h) minimum dimensions for access doors to the prefabricated station in 6.104.4 and for the clear height of service aisles in 6.105.3 have been introduced; i) the continuous current test procedures (heating tests) have been revised/clarified where necessary; j) Figure D.1, which includes the load factor of mineral oil-filled power transformers in the housing, has been corrected.