1. Voltage:
(1) The normal range of fluctuation of the generator voltage is ± 5% Ue, the maximum operating voltage shall not exceed 10% of the rated voltage. The voltage is varies within the normal range, at this moment, the power is in rated value and the rated output of the generator is unchanged.
(2) When the generator voltage drops by 5% Ue, the stator current is allowed to increase by 5% Ie, if the voltage continues to decrease, the stator current must not exceed 10% of Ie. In case of emergency, in order to adjust the allowable current fluctuation ± 10 % Ie of the system voltage , at this moment,, the rotor current must not exceed the rated value.
2. Current:
During generator normal operation, the three-phase unbalanced current shall not exceed 10% Ie, and any one phase shall not exceed the rated value.
3. Cycle:
Generator cycle allowable range of variation is ± 0.5HZ. Within this range, each valve of the generator rated value is unchanged.
4. Power:
Generally the generator is operating over 0.95 of phase-lag, in order to ensure the static stability of the generator, the ratio of generator reactive power load and active load shall be in 3 / 4 to 1 / 2,  holding power within the range of 0.8-0.95 of phase-lag.
5. Leading-phase operation of the generator is not allowed.
6. Temperature:
(1) The generator inlet air temperature shall be kept in 20 ℃ -40 ℃, the lowest temperature of the inlet air to the air cooler is subject to no condensation of water droplets, the highest normally not exceed 40 ℃, under exceptional circumstances, it shall not exceed 55 ℃ .
(2) The generator outlet air temperature is not specified, but in general the inlet and outlet temperature difference should be in 20 ℃ -30 ℃ , if significant temperature difference increases, it indicates that the generator cooling system is not working properly, it is required to take measures to analyze the reasons for eliminating.
(3) As for the temperature-rise of each part of the generator, it is specified that the temperature rise of stator winding of iron core shall not exceed 80 ℃, the rotor winding temperature –rise shall not exceed 90 ℃, normally the stator temperature does not exceed 90 ℃.
(4) The oil inlet temperature of lubrication oil of the generator bearings is 35 ℃ -45 ℃, and the oil outlet temperature shall not exceed 65 ℃, which are the same with those of the steam turbine.