IEEE C37.121-2012 IEEE Guide for Switchgear—Unit Substation—Requirements

IEEE C37.121-2012 IEEE Guide for Switchgear—Unit Substation—Requirements.
4.3 Unusual service conditions For unit substations that are to be applied under conditions other than those in 4.2, see 11.2 for guidance. 5. Transformer section Transformer sections should meet the requirements of this guide and shall comply with the requirements of their applicable standards, including the standard kVA ratings listed in Table 1. Furthermore, the rated high voltage and rated low voltage shall be used in combination with the standard kVA ratings that are listed in Table 2 and Table 3. Primary unit substation transformers should be of the types in 5.1. Secondary unit substation transformers should be of the types in 5.2. 5.1 Primary unit substation transformers 5.1.1 Liquid-immersed without load-tap-changing These transformers shall meet the following requirements: a) Voltage and kVA combinations as indicated in Column 1, Column 2, and Column 5 of Table 2 b) The requirements of IEEE Std C57.12.10 and IEEE Std C57.12.36™ [B17] 5.1.2 Liquid-immersed with load-tap-changing These transformers are not covered in this guide. 5.1.3 Ventilated dry-type, including those with solid-cast or resin-encapsulated windings These transformers shall meet the following requirements: a) Voltage and kVA combinations as indicated in Column 1, Column 2, and Column 3 of Table 2 b) The requirements of IEEE Std C57.12.01 and IEEE Std C57.12.50 and the requirements for solid cast-resin units 5.1.4 Sealed dry-type These transformers shall meet the following requirements: a) Voltage and kVA combinations as indicated in Column 1, Column 2, and Column 4 of Table 2 b) The requirements of IEEE Std C57.12.01, IEEE Std C57.12.52, and UL 1562
5.2 Secondary unit substation transformers 5.2.1 Liquid-immersed without load-tap changing These transformers shall meet the following requirements: a) Voltage and kVA combinations as indicated in Column 1, Column 2, and Column 5 of Table 3 b) The requirements of IEEE Std C57.12.10 and IEEE Std C57.12.36 [B17] 5.2.2 Ventilated dry-type, including those with solid-cast or resin-encapsulated windings These transformers shall meet the following requirements: a) Voltage and kVA combinations as indicated in Column 1, Column 2, and Column 3 of Table 3 b) The requirements of IEEE Std C57.12.51 5.2.3 Sealed dry-type These transformers shall meet the following requirements: a) Voltage and kVA combinations as indicated in Column 1, Column 2, and Column 4 of Table 3 b) The requirements of IEEE Std C57.12.01 or IEEE Std C57.12.52, and UL 1562 6. Incoming section Incoming sections should meet the requirements of this guide and shall comply with the requirements of their applicable specifying standards. Incoming sections may include the components described in 6.1 to 6.6. NOTE—Figure 1 to Figure 10 are shown with the high-voltage section on the left of the figures and the low-voltage section on the right.
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