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 ＝∣
1.3 function configurationFunction configuration of SAI3880D digital generator differential protection deviceDifferential quick break, ratio brake differential, CT disconnection locking differential, CT disconnection alarm, stator overvoltage protection, stator ground fault protection, overload alarm, anti time overcurrent protectionFunction configuration of backup protection device for SAI3881D digital generatorTransverse differential protection, loss of excitation protection, rotor one point grounding protection, rotor two points grounding protection composite voltage over current protection, inverse time negative sequence overcurrent protection, Pt disconnection alarm, non electricity protection (generator water shutoff, and the generator thermal, generator excitation accident, main steam valve closed),
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
2.2.4 precision of various components
Current component: <5%
Voltage components: <5%
Time element: 0s-1s, the error is not more than 40ms;
1s above, the error is not more than < + 2.5%;
Frequency deviation: <0.02Hz
2.2.5 the entire set of action time (including the inherent time of the relay)
Time of motion of a fast moving segment:
1.2 times the value of the entire set of measurement, not more than 50ms
2.2.6 transient transcendence
No more than 5%
2.2.7 og measurement loop accuracy
Measurement and control device for installing special measurement sub module:
Current, voltage: 0.2
Power and electric degree: 0.5
2.3 insulation performance
2.3.1 insulation resistance
Device for charged and uncharged part and a casing and electrical contact of the circuit between the open circuit voltage of 500V megohm meter measuring the insulation resistance value, normal test atmospheric conditions, the circuits of each class of insulation resistance should not be less than 100m ohm.
2.3.2 medium strengthUnder normal test conditions, the device can withstand the frequency of 50Hz, voltage 2000V lasted 1 minutes of power frequency voltage withstand test without breakdown flashover and component damage. During the test, the other circuit is connected to the ground with the other circuit when the voltage is applied.
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