IEEE C50.13-2005 – IEEE Standard for Cylindrical-Rotor 50 Hz and 60 Hz Synchronous Generators Rated 10 MVA and Above.
Abstract: The requirements in this standard are applied to 50 Hz and 60 Hz, two-pole and fourpole, cylindrical-rotor synchronous generators driven by steam turbines and/or by combustion gas turbines. The drive may be direct or through a gearbox or other device that permits different speeds for the turbine and the generator. The generators covered by this standard are to have rated outputs of 10 MVA and above.
Keywords: ac generator, combustion gas turbine generator, cylindrical-rotor generator, steam turbine generator, synchronous generator, turbine generator.
The requirements in this standard apply to all 50 liz and 60 Hz, two-pole and four-pole, cylindrical-rotor synchronous generators driven by steam turbines and/or by combustion gas turbines. The drive may be direct or through a gearbox or other device that permits different speeds for the turbine and the generator.
The generators covered by this standard are to have rated outputs of 10 MVA and above. Cylindrical-rotor, two-pole and four-pole generators below this rating are generally covered by NEMA MG 1-2003.
4. Operational requirements
4.1 Service conditions and steady-state duty
4.1.1 Matching the generator to the turbine power output
Because of the wide range of possible cycles, especially when combustion turbines are used, it is important to examine the match between the generator output and the turbine output very carefully, to ensure that the generator is capable of accepting the maximum output that the turbines are capable of producing. Generators are typically rated at a single point in the output range, defined by the cold gas temperature in the machine (see 5.1). Particular care must be taken if the generator primary coolant is supplied from heat exchangers, as is commonly the case if a water source is used as a secondary coolant.
4.1.1.1 Simple cycle steam turbines
The power output of a steam turbine operating in a simple cycle configuration is relatively independent of the ambient conditions of temperature (humidity, etc.). The generator for this type of’ steam turbine is given a base rating that is usually dependent on the output of the steam turbine with the steam valves wide open and with the boiler at overpressure. It is usually sufficient to ensure that the generator capability (at rated power factor and maximum expected secondary coolant temperature) is sufficient at this operating condition.
4.1.1.2 Simple cycle combustion turbines
Combustion gas turbines fbr simple cycle power plants usually carry two power ratings, base capability and peak capability, that correspond to different combustion temperatures. Generators for these turbines are generally designed for both base capability and peak capability.
Power output from a combustion turbine that operates without any form of power augmentation is a strong function of the inlet air-mass flow rate, and thus is a strong function of the inlet air temperature and atmospheric pressure. If the inlet air is the ambient air at the site, then the combustion turbine output is strongly dependent on the ambient air temperature, falling off as the ambient temperature rises. The generator must match the turbine output over the designated ambient-temperature range.IEEE C50.13 pdf download.