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关 键 词:专业定做发电机保护测控装置加工
行 业:电气 电气成套设备 变电站
发布时间:2020-11-12
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
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.
2.3.3 impulse voltageIn the normal test atmospheric conditions, device power input circuit, the AC input circuit, output contact circuit and loop between, can withstand the 50s of the standard lightning wave short-time impulse voltage test, open test voltage 5kV.
2.3.4 resistance to damp heat resistance
The device can withstand the damp heat test specified in the twenty-first chapter of the GB7261. The highest temperature test + 40 DEG C, maximum relative humidity of 95%, the test time for 48 hours, each cycle lasted 24 hours of cyclic damp heat test, at the end of the test within 2 hours before according to the requirement 2.3.1, measure the circuits between the conductive circuit foreign Lufei charged metal part and the shell, electrical contact between the insulation resistance is not less than 1.5m ohm, medium compressive strength of not less than 75% of the 2.3.2 provisions of the dielectric strength test voltage amplitude.
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.