Table 72. Load shedding (LSHDPFRQ)
Characteristic
Value
Operation accuracy
f<
±10 mHz
df/dt
±100 mHz/s (in range |df/dt| < 5 Hz/s)
± 2.0% of the set value (in range 5 Hz/s < |df/
dt| < 15 Hz/s)
Start time
f<
< 80 ms
df/dt
< 120 ms
Reset time
< 150 ms
Operate time accuracy
±1.0% of the set value or ±30 ms
Table 73. Load shedding (LSHDPFRQ) main settings
Parameter
Function
Value (Range)
Step
Load shed mode
LSHDPFRQ
Freq<
Freq< AND df/dt
Freq< OR df/dt
-
Restore mode
LSHDPFRQ
Disabled
Auto
Manual
-
Start value Freq
LSHDPFRQ
0.800...1.200 x Fn
0.001
Start value df/dt
LSHDPFRQ
-0.200...-0.005 x Fn
0.005
Operate Tm Freq
LSHDPFRQ
80...200000 ms
10
Operate Tm df/dt
LSHDPFRQ
120...200000 ms
10
Restore start Val
LSHDPFRQ
0.800...1.200 x Fn
0.001
Restore delay time
LSHDPFRQ
80...200000 ms
10
Transformer Protection and Control
1MRS757846 A
RET620
Product version: 2.0
44
ABB