光纤差动保护原理
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光纤差动保护原理
光纤电流差动保护是一种基于克希霍夫基本电流定律的保护方式,它通过光纤传输通道实时传递采样数据,利用本地和对侧电流数据按相进行差动电流计算,从而判断是否发生区内故障并进行跳闸保护。相比于其他保护形式,光纤电流差动保护具有灵敏度高、动作简单可靠快速、能适应电力系统震荡、非全相运行等优点。同时,由于两侧的保护装置没有电联系,提高了运行的可靠性。
光纤分相电流差动保护的典型构成如图1所示,其差动保护一般采用双斜率制动特性,以保证发生穿越故障时的稳定性。制动特性曲线采用不同的制动斜率,可以在小电流时提高灵敏度,在电流大时提高可靠性。当线路末端发生区外故障时,采用较高斜率的制动特性更为可靠。在光纤分相电流差动保护中,线路两侧电流大小相等方向相反时,差电流为零,反之则不为零,当满足电流差动保护的动作特性方程时,保护装置会发出跳闸令快速将故障相切除。
光纤电流差动保护以其可靠稳定的光纤传输通道保证了传送电流的幅值和相位正确可靠地传送到对侧,因此在电力系统的主变压器、线路和母线上得到广泛应用。通过光纤传输通道实时传递采样数据,光纤电流差动保护实现了保护实现单元化,原理简单,不受运行方式变化的影响。
程序。该元件的启动门槛为定值加上浮动门槛,延时30ms以确保相电流突变量元件的优先动作。
3.1.4利用TWJ的辅助启动元件
该元件通过TWJ信号传输实现对侧启动,当本侧未启动且对侧启动时,TWJ信号发出,本侧启动元件动作。同时,为了确保对侧启动元件不受到本侧故障影响,需要在对侧设置QDS信号,当QDS=1时,对侧启动元件才能动作。
分相电流差动保护采用专用光缆或2M数字通道传输三相电流及其他数字信号,使用专用光缆作为通信媒介时,传送速率可达1Mbps,内置式光端机不需要任何光电转换设备即可独立完成光电转换过程。差动继电器动作速度快,跳闸时间小于25ms,即使在经过大接地电阻故障,故障电流小于额定电流时,也能在30ms以内正确动作。零序电流差动保护提高了整个装置的灵敏度,增强了耐过渡电阻能力。 分相电流差动保护主要由差动CPU模件和通信接口组成,差动CPU模件完成采样数据读取、滤波、数据发送、接收、数据同步、故障判断、跳闸逻辑出口;通信接口完成与光纤的光电物理接口功能,另外专门加装的PCM复接接口装置则完成数据码型转换,时钟提取等同向接口功能。
保护启动元件包括相电流突变量启动元件、零序辅助启动元件、低电压启动元件和利用TWJ的辅助启动元件。相电流突变量启动元件作为主要启动元件,启动门槛由突变量启动定值加上浮动门槛确定,零序电流辅助启动元件和静稳破坏检测元件作为辅助启动元件。低电压辅助启动元件用于弱馈负荷侧,利用TWJ的辅助启动元件通过TWJ信号传输实现对侧启动。保护启动元件用于启动故障处理程序及开放保护跳闸出口。
This device has long-distance jumping n and two remote
signal channels。which can be used to achieve long-distance
jumping and remote signal ns。When used for long-distance
jumping。after the opening is confirmed for 8ms。it is packaged
together with digital n and sampling data。encoded。and CRC
checked。and then sent to the opposite side after being XXX。after receiving the data from the opposite side。it is CRC checked。decoded and the long-distance jumping signal XXX。Only when the long-distance jumping signal from the opposite side is received
three times in a row。the exit tripping is confirmed。When long-distance jumping is used for direct tripping。it can be locked by
local start-up XXX control word is set to long-distance jumping
through local start-up interlock。if no tripping occurs within
500ms after receiving the long-distance jumping signal from the
opposite side。the n will send a message of "long-term unreturned
tripping signal"。Also。when used for remote signal n。after the
opening is confirmed for 5ms。it is sent to the opposite side
through the same processing as long-distance jumping signal.
XXX:
1) According to the n of the two sets of n。as long as one set
of n is put into n。it is required that the operating power supplies
(in the n screen) of the two sets of n are in the operating n。The
reason is that the GPSL603 XXX control device。while the WXH-803 XXX with an n box。Because of the inseparability of these
two。the above requirements are made.
2) When the WXH803 device has a fault or needs to。all n。the tripping outlet pressure plate should be disconnected first。and then the DC power supply should be disconnected。When the
device sends a "Alarm I" signal。it is generally caused by
hardware abnormalities。incorrect values。and sampling errors。etc。which will also lock the +24V power supply of the n outlet
loop。It is XXX.
3) XXX at the same time。When the channel is abnormal or
faulty。XXX。If only one side of the differential pressure plate is
withdrawn。the other side will give a "XXX" message and lock
the XXX.
4) When the device is restarted after being tripped。only the
tripping outlet pressure plate should be disconnected。and the
reclosing method should be consistent with the reclosing method
of the other operating reclosing。It is not allowed to be placed in
the "disabled" n alone.
GPSL603 XXX:
During normal n。the "n" indicator light is on and the other
indicator lights are off。The reasons for the device alarm and the
XXX:
Event name
RAM error
XXX
XXX
XXX
AD error
XXX drift exceeds limit
XXX
XXX
Flash memory error
Internal power supply is low
PT reverse sequence
CT imbalance
CT reverse sequence
Load asymmetry
PT n
XXX XXX.
WXH803 device abnormal alarm and its handling: When normal。the "n" light is green and always on。the
"Alarm I"。"Alarm II" and other tripping lights are not lit。The
reasons for the abnormal alarm of the device and its XXX:
Signal light
Display XXX
Fault reason
XXX
Handling measures: alarm。call for help。shut down for
maintenance。lock n。call for help。check PT circuit。check CT
circuit。switch to valid value zone。re-enter correct values。for
maintenance.
Note: The article has been edited for XXX.