专业订制发电机保护测控装置*代理 南瑞

深圳南网国瑞科技有限公司

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 ＝∣

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.
3.9 inverse time negative sequence overcurrent protectionPower system occur asymmetric short-circuit and three-phase load imbalance may be the negative sequence current flowing in the stator winding of the generator, and produce harmonic current in the rotor, rotor surface overheating caused, generator's inverse time negative sequence over the protection of rotor flow under the situation not long overheated rotor insulation degradation caused damage to the generator, discrimination protection of generator stator negative sequence current size, consists of three parts:
1) under the time limit: when the negative sequence current is greater than the lower bound value but does not meet the start value of the anti time limit, the alarm signal is delayed by the lower limit;
2) inverse time: when the negative sequence current is larger than the inverse time start value, according to the inverse time lag action equation I22-K t is equal to or larger than a action, type: I2-- generator negative sequence current standard? Value, K - generator operation value of negative sequence current in the standard, a generator rotor surface bear negative sequence current capability of constant;
3) the upper bound limit: when the negative sequence current is greater than the upper bound limit, the upper limit is delayed by the time delay.

device overview
SAI3880D series digital generator protection device with high performance chip supports universal hardware platform, easy to maintain; the Ethernet communication, high-speed data transmission and reliable. Complete localization of Chinese display technology, simple operation.
Based on waterproof, dust, anti vibration design, can be run in a variety of field conditions.
Suitable for capacity of 50MW and below the fire and hydro generator protection.
1.2 main features of the device
An Motorola 32 bit microcontroller technology, the stability and speed of products is guaranteed
The protection. The 14 bit a / D converter, optional measurement module dedicated to the A / D conversion accuracy is up to 24 bits and the measurement indicators easily reach
The purpose of configuration with high capacity RAM and Flash Memory, can record 8 to 50 recorded reports, record the number of events is not less than 1000
An independent tuning of 32 sets of protection setting value, safe and convenient switch
In high precision clock chip, and equipped with GPS hardware circuit for the whole time, system clock synchronization
It is equipped with high speed Ethernet communication interface, and the integration of IEC870-5-103 standard communication protocol
In the electrical design with the machine, no adjustable device
In high grade, quality assurance component selection
An excellent anti-interference performance, panel or installed in the switch cabinet without other anti-jamming module
The purpose of self diagnosis function perfect
The chassis design of waterproof and dustproof and anti vibration.
The purpose of debugging conceptual design
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 signal;
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.
2.5 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)
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.