l include the transformers and arc suppression coi
4.1.1 The power transformers shal ls.
4.1.2 Aseismatic appraisal for power transformers shall focus on examination of the installation methods,the connections between the lead wires and external wires,and the strength of the conservator racks and the radiator cantilevers.
4.1.3 In the areas where the aseismatic precautionary intensity is 7 degree and above,aseismatic calculation shall be made in accordance with Chapter 5 of this standard.
4.1.4 Aseismatic appraisal for transformers and arc suppression coils shall meet the following requirements:
1 The transformer and arc suppression coil shall be securely fixed to the foundation.
2 Flexible conductoring shall be provided between the transformer and the external bus.
3 The transformer conservator rack shall be free of any visible deformation,and shall be securely fixed with the main body of the transformer and the conservator.
4 The cantilever radiator of the transformer and the connections shall be in good conditions.
4.1.5 The connection pipe between the independent oil cooler and the main body of the transformer shall be provided with shut-off valve and flexible fitting near to the transformer.
4.1.6 The power transformers installed on the electric poles shall be provided with fixing devices.
4.1.7 If the transformers and arc suppression coils fail to meet the aseismatic appraisal requirements in this section,aseismatic measures shall be taken in accordance with the following provisions:
1 In addition to displacement limit measures,the transformers and arc suppression coil shall be directly bolted or welded to the foundation.
2 If flexible conductors are used for the transformer bushings,proper slack shall be provided.If the insulation clearance fails to meet the specified requirements,spring clamp fittings may be used.If rigid bus is used and the size of bus section is larger than 50mm×5mm,flexible fittings shall be provided.If the aseismatic precautionary intensity is 6 degree or 7 degree,flexible fittings should be provided for the power transformers of 10kV and below.And if the aseismatic precautionary intensity is 8 degree or 9 degree,flexible conductor shall be provided.
3 The cantilever radiator of the transformer may be supported by the angle steel rack installed on the main body of the transformer or fixed circularly around the radiator by using flat steel strips.
4.1.8 The connection pipe between the independent oil cooler and the main body of the transformer shall be provided with shutoff valve and flexible fitting near to the transformer,and the distance from the radiator,oil-submerged pump and connection pipe to the foundation shall not be less than 200mm.
4.1.9 The bottom of transformers installed on electric pole shall be bolted to the lower beam.In the area where the aseismatic precautionary intensity is 8 degree and above,fixing devices should be also provided between the upper portion of the transformer and the electric pole.