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Load
shedding
control
ST_FRQ
OPR_FRQ
Restore
detection
Under
frequency
detection
df/dt
detection
ST_FRG
OPR_FRG
ST_REST
START
U3P
BLOCK
BLK_REST
OPERATE
RESTORE
MAN_RESTORE
Blocking
logic
dF/dt
F
Figure 516: Functional module diagram
Underfrequency detection
The underfrequency detection measures the input frequency calculated from the
voltage signal. An underfrequency is detected when the measured frequency drops
below the set value of the
Start value Freq setting.
The underfrequency detection module includes a timer with the definite time (DT)
characteristics. Upon detection of underfrequency, operation timer activates the
ST_FRQ
output. When the underfrequency timer has reached the value set by
Operate Tm Freq, the
OPR_FRQ
output is activated if the underfrequency condition
still persists. If the frequency becomes normal before the module operates, the
reset timer is activated. If the reset timer reaches the value set by
Reset delay time,
the timer resets and the
ST_FRQ
output is deactivated.
df/dt detection
The df/dt detection measures the input frequency calculated from the voltage
signal and calculates its gradient. A high df/dt condition is detected by comparing
the gradient to the
Start value df/dt setting. The df/dt detection is activated when
the frequency gradient decreases at a faster rate than the set value of
Start value
df/dt.
Protection functions
1MRS759142 F
930
REX640
Technical Manual
Содержание RELION REX640
Страница 1: ... RELION PROTECTION AND CONTROL REX640 Technical Manual ...
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Страница 3: ...Document ID 1MRS759142 Issued 2023 02 07 Revision F Copyright 2023 ABB All rights reserved ...
Страница 167: ...Figure 62 Signal outputs in power supply module 1MRS759142 F Basic functions REX640 Technical Manual 167 ...
Страница 184: ...Figure 84 mA channels working as mA outputs Basic functions 1MRS759142 F 184 REX640 Technical Manual ...
Страница 1868: ...Figure 989 ANSI extremely inverse time characteristics General function block features 1MRS759142 F 1868 REX640 Technical Manual ...
Страница 1869: ...Figure 990 ANSI very inverse time characteristics 1MRS759142 F General function block features REX640 Technical Manual 1869 ...
Страница 1870: ...Figure 991 ANSI normal inverse time characteristics General function block features 1MRS759142 F 1870 REX640 Technical Manual ...
Страница 1874: ...Figure 995 ANSI long time inverse time characteristics General function block features 1MRS759142 F 1874 REX640 Technical Manual ...
Страница 1875: ...Figure 996 IEC normal inverse time characteristics 1MRS759142 F General function block features REX640 Technical Manual 1875 ...
Страница 1876: ...Figure 997 IEC very inverse time characteristics General function block features 1MRS759142 F 1876 REX640 Technical Manual ...
Страница 1877: ...Figure 998 IEC inverse time characteristics 1MRS759142 F General function block features REX640 Technical Manual 1877 ...
Страница 1878: ...Figure 999 IEC extremely inverse time characteristics General function block features 1MRS759142 F 1878 REX640 Technical Manual ...
Страница 1882: ...Figure 1002 RI type inverse time characteristics General function block features 1MRS759142 F 1882 REX640 Technical Manual ...
Страница 1885: ...Figure 1004 UK rectifier inverse time characteristic 1MRS759142 F General function block features REX640 Technical Manual 1885 ...
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