BS EN 62271-202:2014

What is BS EN 62271‑202‒ High-voltage/low-voltage prefabricated substation about?

BS EN 62271‑202 is a part of an international multi-series standard that covers general specifications for high-voltage switchgear and control gear.

BS EN 62271‑202 specifies the service conditions, rated characteristics, general structural requirements, and test methods of high voltage/low voltage or low voltage/high voltage prefabricated substations. These are cable-connected, that are to be operated from the inside (walk-in type) or outside (non-walk-in type) for alternating current of rated voltages above 1 kV and up to and including 52 kV on the high voltage side.

BS EN 62271‑202 also specifies prefabricated substations that include an operation for one or more transformers for service frequencies up to and including 60 Hz for outdoor installation at locations with public accessibility and where protection of personnel is provided.

Prefabricated substations can be situated at ground level or partially or completely below ground level.

In general, a prefabricated substation comprises an enclosure containing the following electrical components:

• Power transformers
• High voltage and low voltage switchgear and controlgear
• High voltage and low voltage interconnections
• Auxiliary equipment and circuits

However, relevant provisions of BS EN 62271‑202 are applicable to designs where not all these electrical components exist such as an installation consisting of a power transformer and low voltage switchgear.

Note: Non-prefabricated substations should comply with the applicable requirements of IEC 61936-1:2010.

Who is BS EN 62271‑202‒ High-voltage/low-voltage prefabricated substation for?

BS EN 62271‑202 on High-voltage/low-voltage prefabricated substation is useful for:

• Fabricators of high-voltage/low voltage switchgear and controlgear substations
• Designers and developers of high-voltage/low voltage switchgear and controlgear substations
• Installers/ certification providers for high-voltage/low voltage switchgear and controlgear substations
• Regulatory authorities for high-voltage/low voltage switchgear and controlgear substations
• Dealers and distributors of high-voltage switchgear and controlgear

Why should you use BS EN 62271‑202‒ High-voltage/low-voltage prefabricated substation?

Prefabricated substations are defined as a type-tested assembly comprising an enclosure containing in general transformers, low-voltage and high-voltage switchgear, connections, and auxiliary equipment to supply low-voltage energy from a high-voltage system or vice versa.

BS EN 62271‑202 presents you with all the features that should be outfitted in the high-voltage/low-voltage prefabricated substation. It gives information about the accessible location of these substations, to the public and helps the users ensure the protection of persons according to the specified service conditions.

BS EN 62271‑202 stipulates the specified characteristics, ratings, and relevant test procedures, and pays particular attention to the specification concerning the protection of persons, both operators, and the general public. It talks about the use of type-tested components and suitable design and construction of the enclosure in order to ensure the safety of the persons.

Thus, BS EN 62271‑202  describes the correct design and performance of the prefabricated substation, which are verified by means of relevant type tests, including internal arc tests.

What’s changed since the last update?

BS EN 62271‑202:2014 supersedes BS EN 62271-202:2007, which is withdrawn. The main technical changes compared to the first edition are the following:

• Regarding the temperature-rise test an alternative method for liquid-filled transformers is (re)introduced and the temperature-rise test method for dry-type transformers is specified more precisely
• The testing procedure for a short time and peak withstand current tests are specified more precisely Assessment of electromagnetic fields is considered including a typing test (optional) according to CLC/TR 62271-208:2010
• The influence of the product on the environment is considered (Clause 12)
• Internal arc test requirements have been adapted to EN 62271-200:2012 and requirements for the assessment of pressure relief volumes below the floor/ground has been assigned
• The method for defining the load factor in an enclosure for liquid-filled transformers is extended with different temperature rises for the transformer outside the enclosure (Annex DD)
• For the calculation of the load factor of dry-type transformers in an enclosure the insulation systems according to EN 60076-1:2011, Tables B.1 and B.2 are worked out in detail