Prefabricated Substation National Standard
(1) Rated voltage: for high-voltage switchgear and control equipment, according to GB/T 11022. For low-voltage switchgear and control switchgear, according to GB/T 14048.1 and GB 7251.1.
(2) Rated insulation level: for high-voltage switchgear and control equipment, according to GB/T 11022; for low-voltage switchgear and control equipment, according to GB/T 14048.1 and GB 7251.1. The minimum rated impulse withstand voltage of low-voltage switchgear and control equipment shall be at least the given value of Class IV overvoltage in Table 1 of GB/T 16935.1-1997.
(3) Rated frequency and number of phases: according to GB/T 11022, GB/T 14048.1 and GB 7251.1.
(4) Rated current and temperature rise: The rated current is in accordance with GB/T 11022 and GB 7251.1. The temperature rise of high-voltage switchgear and control switchgear is in accordance with GB/T 11022, and the temperature rise of low-voltage switchgear and controlgear is in accordance with GB 7251.1.
(5) Rated short-time withstand current: for high-voltage switchgear and control switchgear, according to GB/T 11022; for low-voltage switchgear and control switchgear, according to GB 7251.1; for transformers, according to IEC 76-5 and GB 6450.
(6) Rated short-circuit duration: for high-voltage switchgear and control equipment, according to GB/T 11022; for low-voltage switchgear and control equipment, according to GB 7251.1.
(7) Rated power supply voltage of operating mechanism and auxiliary circuit: for high-voltage switchgear and control switchgear, according to GB/T 11022; for low-voltage switchgear control equipment, according to GB 7251.1.
(8) Rated power frequency of operating mechanism and auxiliary circuit: for high-voltage switchgear and control equipment, according to GB/T 11022; for low-voltage switchgear control equipment, according to GB 7251.1.
(9) The rated maximum capacity of the prefabricated substation: The rated maximum capacity of the prefabricated substation is the maximum rated value of the transformer specified when the substation was designed.
(10) Grounding: In addition to GB/T11022, it should also meet the following requirements. A grounding conductor shall be provided connecting each element of the prefabricated substation. The current density of the grounding conductor, such as copper conductor, should not exceed 200A/mm2 when the rated short-circuit duration is 1s, and should not exceed 125A/mm2 when the rated short-circuit duration is 3s; but its cross-sectional area should not be less than 30mm2. Its ends should have suitable terminals for connection to the grounding system of the installation.
(11) Auxiliary equipment: For low-voltage devices (such as lighting, auxiliary power supply, etc.) in prefabricated substations, if applicable, according to GB/T 14821.1 or GB7251.1 Protection class: prevent personnel from touching dangerous parts and prevent foreign objects from entering and moisture immersion protection of the device is required.
(12) Main wiring design and primary equipment selection The protection level of the prefabricated substation enclosure should not be lower than the IP23D in GB4208. The higher protection level can be specified according to GB4208.
