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 ＝∣
2.2 Main technical performance
Precise working range of 2.2.1 sampling circuit (10% error)
Voltage: 0.4 V ~ 120V
Current: 0.08In20In
2.2.2 contact capacity
Signal circuit contact current carrying capacity 400VA
Signal circuit contact fault arc capacity 60VA
2.2.3 tripping current
Breaker trip current 0.5A~4A (order indication)
The circuit breaker closing current 0.5A~4A (the order stated)
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
2.5 mechanical properties
2.5.1 vibration
The device can withstand the vibration endurance test of the I level of 16.3 in the GB7261.
2.5.2 impact
The device can withstand the impact endurance test of the I level of 17.5 in the GB7261.
2.5.3 collision
The device can withstand the impact endurance test of the GB7261 level of I in the eighteenth chapter.
2.6 environmental conditions
A) ambient temperature: Work: -40 C ~ 85.
Storage: 25 degrees to +70 degrees Celsius, in the limit value does not apply the amount of incentive, the device does not appear irreversible change
After the temperature is restored, the device should be able to work properly.
Relative humidity: the maximum monthly average relative humidity of 90%, while the average monthly average of.
The lowest temperature is 25 DEG C and no condensation surface. When the maximum temperature of +40 degrees Celsius, the average maximum relative humidity
Degree no more than 50%.
(c) atmospheric pressure: 86 to 106kPa (relative altitude below 2km)
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
AC measurement
A group of three-phase current, three-phase voltage and zero sequence voltage, power, frequency, power, power factor
Switch input
11 way switch input, can be the whole set of non electric power for "trip" or "alarm", the first 4 non electricity can be arbitrarily set trip exit
Switch output
8 way switch contact output, the 4 switch jump closing control
control loop
Jump control circuit, circuit breaker hand jump, hand closing operation and hop position indication
1)under the time limit: when the three-phase current is greater than the lower limit of the value of any phase, but not meet the anti time limit start value, press the lower limit delay action on the alarm **;
2) inverse time: when the three-phase current any phase current is larger than the inverse time starting value, according to the inverse time lag action equation I2-1 t is greater than or equal to K acts, type: I for the generator current standard? Value, K - generator stator winding allows thermal time constant.
3) the upper bound limit: when the three-phase current is greater than the upper limit value, the time limit is delayed by the time limit.
3.8 transverse differential protection
Generator transverse differential protection is usually used for the reaction of generator stator winding inter turn short circuit and a parallel windings open welding, protection from the generator neutral point between two branch imbalance fundamental current, but current is greater than fixed value setting delay action on the alarm or trip.
2.4 electromagnetic compatibility
2.4.1 electrostatic discharge reactance
Through the GB/T 17626.21998 standard, electrostatic discharge immunity test IV.
2.4.2 radio frequency electromagnetic field radiated immunity
Through the GB/T 17626.31998 standard, RF electromagnetic field immunity test level 3.
2.4.3 electric fast transient pulse group immunity
GB/T 1998 - 17626.4 standard, electrical fast transient pulse group immunity test.
2.4.4 surge (impact) immunity
Through the GB/T 1999 - 17626.5 standard, surge (impact) immunity test 3.
Conduction disturbance degree of 2.4.5 RF field induction
Through the GB/T 17626.61998 standard, RF induction level 3 test conducted
2.4.6 power frequency magnetic field immunity
Through the GB/T 1998 - 17626.8 standard, the power frequency magnetic field immunity 5 level test
2.4.7 pulse magnetic field immunity
Through the GB/T 1998 - 17626.9 standard, the pulse magnetic field immunity 5 level test.
2.4.8 damped oscillatory magnetic field immunity
Through the GB/T 1998 - 17626.10 standard, damped oscillatory magnetic field immunity test 5 levels of test.
2.4.9 oscillation wave immunity
Through the GB/T 1998 - 4 standard, 17626.12 - level oscillation wave immunity test.
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.
3.10 stator overvoltage protection
For generator, in particular to a hydro generator, after load rejection due to the speed control of speed control system can not keep up, is easy to appear the stator voltage exceeds the allowed range of over voltage phenomena; at this point to be equipped with over voltage protection, protection from the generator terminal voltage when any phase of more than setting value by setting the delay action to stop.
3.11 stator ground protection
Generator stator grounding protection can for the generator neutral point ungrounded or via arc suppression coil grounding grounding, protection from the generator end opening of the delta winding voltage when open delta windings voltage greater than setting value by setting the exit delay.
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