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关 键 词：专业生产发电机保护测控装置
行 业：电气 电气成套设备 变电站
发布时间：2020-11-05
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.
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.
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
