MT 29 - TC 17/SC 17C/MT 29

IEC 62271-202:2022 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.
This third edition cancels and replaces the second edition published in 2014. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous edition:
the whole document contents and structure are reviewed with due consideration of IEC 62271-1:2017;
modification of the title and scope to include high-voltage switchgear prefabricated substations;
inclusion of CEADS as a possible component of MV/LV prefabricated substation;
in 7.2.101, the possible influence of surrounding elements on the dielectric performance of high-voltage components as high-voltage switchgear and controlgear and high-voltage interconnections non-metal-enclosed or without earthed screen are now considered;
new informative Annex G with testing procedure to evaluate the impact of solar radiation in temperatures inside the enclosure and how to apply it;
new informative Annex H for appropriate consideration of installation conditions of electronic equipment;
the rated power of a prefabricated substation is now defined as a three-parameter rated value. See 5.101.1;
minimum dimensions for access doors to the prefabricated substation in 6.104.4 and for free height of operation aisle in 6.105.3 have been introduced;
continuous current (temperature rise) test methods have been revised/clarified where necessary;
Figure D.1, which shows the mineral-oil-immersed power transformer load factor inside the enclosure, has been corrected.

IEC 62271-202:2022 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.
This third edition cancels and replaces the second edition published in 2014. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous edition:
the whole document contents and structure are reviewed with due consideration of IEC 62271-1:2017;
modification of the title and scope to include high-voltage switchgear prefabricated substations;
inclusion of CEADS as a possible component of MV/LV prefabricated substation;
in 7.2.101, the possible influence of surrounding elements on the dielectric performance of high-voltage components as high-voltage switchgear and controlgear and high-voltage interconnections non-metal-enclosed or without earthed screen are now considered;
new informative Annex G with testing procedure to evaluate the impact of solar radiation in temperatures inside the enclosure and how to apply it;
new informative Annex H for appropriate consideration of installation conditions of electronic equipment;
the rated power of a prefabricated substation is now defined as a three-parameter rated value. See 5.101.1;
minimum dimensions for access doors to the prefabricated substation in 6.104.4 and for free height of operation aisle in 6.105.3 have been introduced;
continuous current (temperature rise) test methods have been revised/clarified where necessary;
Figure D.1, which shows the mineral-oil-immersed power transformer load factor inside the enclosure, has been corrected.
The contents of the corrigendum of August 2023 have been included in this copy.

IEC 62271-202:2014 specifies the service conditions, rated characteristics, general structural requirements and test methods of high voltage/low voltage or low voltage/high voltage prefabricated substations, which are cable-connected, to be operated from 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, and 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. This second edition cancels and replaces the first edition published in 2006. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
a) regarding 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;
b) testing procedure for short time and peak withstand current tests are specified more precisely;
c) assessment of electromagnetic fields is considered including a type test (optional) according IEC/TR 62271-208:2009;
d) influence of the product on the environment is considered (Clause 12);
e) internal arc test requirements have been adapted to IEC 62271-200:2011 and requirements for the assessment of pressure relief volumes below the floor / ground has been assigned;
f) 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);
g) for the calculation of the load factor of dry-type transformers in an enclosure the insulation systems according to IEC 60076-1:2011, Tables B.1 and B.2 are worked out in detail.
This publication is to be read in conjunction with IEC 62271-201:2007. The contents of the corrigendum of April 2015 have been included in this copy.