Technical Data; Load-Shedding And Restoration Lshdpfrq; Identification; Function Block - ABB RELION REX640 Technical Manual

Section 4
Protection functions
4.6.1.10
4.6.2
4.6.2.1
4.6.2.2
4.6.2.3
846

Technical data

Table 813: FRPFRQ Technical data
Characteristic
Operation accuracy f>/f<
df/dt
Start time f>/f<
df/dt
Reset time
Operate time accuracy

Load-shedding and restoration LSHDPFRQ

Identification

Function description
Load-shedding and restoration

Function block

GUID-28B919DC-0884-4DDB-A6C4-27C80809B50E V1 EN
Figure 456: Function block

Functionality

The load-shedding and restoration function LSHDPFRQ is capable of performing
load-shedding based on underfrequency and the rate of change of the frequency. The
load that is shed during the frequency disturbance can be restored once the frequency
has stabilized to the normal level.
The measured system frequency is compared to the set value to detect the
underfrequency condition. The measured rate of change of frequency (df/dt) is
compared to the set value to detect a high frequency reduction rate. The combination
of the detected underfrequency and the high df/dt is used for the activation of the load-
shedding. There is a definite time delay between the detection of the underfrequency
Value
±5 mHz
±50 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)
<80 ms
<120 ms
<150 ms
±1.0% of the set value or ±30 ms
IEC 61850 IEC 60617
identification identification
LSHDPFRQ UFLS/R
1MRS759142 C
ANSI/IEEE C37.2
device number
81LSH
REX640
Technical Manual