JB/T 8990-1999 (English Version) PDF

Scope: This standard specifies the modal test analysis and natural frequency measurement methods and evaluation criteria for the stator end windings of large steam turbine generators. This standard is applicable to the stator end windings of large turbine generators with rated power of 300 MW and above and rated speeds of 3000 r/min and 3600 r/min (including air cooling, double water cooling, full hydrogen cooling, water hydrogen cooling, etc.) Modal test analysis and natural frequency measurement and evaluation. When large turbine generators undergo type testing in the manufacturing plant, modal test analysis of the stator end windings should be performed. When measuring natural frequencies in a power plant, if it is found that most wire rods have natural frequencies close to the frequency of electromagnetic interference, modal test analysis must also be done. For large turbine generator products, the natural frequency of the stator end winding must be measured before leaving the factory and after overhaul. In power plants, when there are abnormal conditions (for example, sudden short circuit, coil wear or looseness, etc.), natural frequency measurement must be done. For turbine generators below 300 MW, it is decided according to the specific circumstances whether to perform natural frequency measurement after overhaul. Imported units can also refer to this standard.

JB/T 8990-1999 history

1999 JB/T 8990-1999 Model test analyses and natural frequency measurement methods of large turbo - generators on stator end windings and evaluation criteria