The rotor low voltage action criterion equation is： Kf×Vfd/125 < (P-Pt)/866 3.5 Over load protection Generator stator winding protective reaction of load generator stator winding overload or fault caused by overcurrent caused overheating winding, discrimination protection generator winding B phase current size, when the current is higher than setting value when the delay send alarm **. 3.6 compound voltage over current protection Generator compound voltage over-current protection is as a generator of symmetric and asymmetric short-circuit fault back-up protection, protection discriminant generator three-phase current, AC phase voltage and negative sequence voltage, when any phase current is greater than the fixed value, and AC phase voltage less than fixed value or negative sequence voltage is greater than the fixed value export protection settings have two period of time delay, a movement in solution column or splitting demagnetization, off action to stop, protection can choose to take the current memory function. 3.7 inverse time overcurrent protection Generator anti time limit over current protection of the generator stator winding current size, the protection of the winding due to the current too large and lead to the stator winding overheating, the protection of the three-phase current size of the judge, from three parts: Three、Software function deion 3.1. differential quick break protection When any phase difference current is greater than the value of the differential speed, the protection action is stopped. Fast removal of generators in the case of a serious fault in the area of the generator. Differential speed determine the value should be able to avoid the external fault of the maximum unbalanced current, and taking into account the current transformer saturation factor, generally take 3 to 8 times the rated current
3.2.Ratio differential protection Using the conventional ratio differential principle, the equations of motion are as follows: Id > Icd （Ir Ir0） Id - Icd > Kcd ·(Ir- Ir0) (Ir ≥ Ir0) At the same time to meet the above two equations, the ratio of the differential element action. Among them, Id for the differential current, Ir for the braking current, Kcd for Ratio braking coefficient, Icd is the threshold value of the differential current, and Ir0 is the turning point of the current value. It is proposed that the turning point in the component current Ir0 is set to 1 times the rated current of the high voltage side to ensure that the turn to turn short circuit in the braking current is less than the rated current Ie Ir, there is no braking effect. Differential current threshold criterion should not be too small, it is recommended to take Icd = (0.3 ~ 0.5) Ie. The setting of the ratio braking coefficient can be carried out according to the following formula: Kcd = Kk (Ktx / Fwc + Fph) Among them, Kk is the reliable coefficient, take 1.3 ~ 1.5 Ktx for the same type coefficient, take 1 Fwc for the current transformer to allow the error, take 0.1 The Fph for the current caused by current transformer unbalanced relative error is 0.05. Ratio braking coefficient Kcd recommended range of 0.3 to 0.7.Id ＝∣ Two technical parameter 2.1 Rated parameters 2.1.1Rated DC voltage： 220V or 110V (order indicated) 2.1.2 Rated AC data： a) Phase voltage V
