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.
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)the maximum phase current of a side is less than 20% of the rated current, it is not sentenced to the side;
2)2) the maximum value of the phase current is greater than 120% of the rated current of the side;
3)3) served as the start of one side of the current than before the start of the increase.In the case of the above three conditions are not satisfied, such as one side at the same time meet the following conditions, then sentenced to CT break:
1)only one phase current is zero;
2) the remaining two phase currents are equal before starting the current.
3.3.2 differential current limit alarmIf the difference is greater than 15% of the rated current, after more than 10s discriminant, issued a warning **. Differential current limit, but not locked differential protection. The function and the monitoring function of the AC sampling circuit of the protection device
3.4 loss of magnetic protection
Generator loss of excitation protection for generator excitation current abnormal decrease or disappear completely lost magnetic fault protection, by the generator stator impedance as the main criterion, combined with low voltage and generator excitation system low voltage as auxiliary criterion, and have TV disconnection locking function, TV break send alarm **.
Its action logic is as follows:
-/gjigcb/-
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