U=-3U0
Operate region
RCADir
ROADir
Ipickup
I=3Io
mta line
F
en05000253.vsd
IEC05000253 V1 EN
Figure 273:
CVGAPC, IcosPhi&U directional operating principle
where:
RCADir is -75°
ROADir is 50°
Note that it is possible to decide by a parameter setting how the directional feature
shall behave when the magnitude of the measured voltage phasor falls below the pre-
set value. User can select one of the following three options:
•
Non-directional (operation allowed for low magnitude of the reference voltage)
•
Block (operation prevented for low magnitude of the reference voltage)
•
Memory (memory voltage shall be used to determine direction of the current)
It shall also be noted that the memory duration is limited in the algorithm to 100 ms.
After that time the current direction will be locked to the one determined during
memory time and it will re-set only if the current fails below set pickup level or voltage
goes above set voltage memory limit.
Voltage restraint/control feature
The overcurrent protection step operation can be made dependent of a measured
voltage quantity (see table
). Practically then the pickup level of the overcurrent
step is not constant but instead decreases with the decrease in the magnitude of the
measured voltage quantity. Two different types of dependencies are available:
•
Voltage restraint overcurrent (when setting parameter
VDepMode_OC1
=
Slope
)
1MRK502052-UEN B
Section 11
Multipurpose protection
581
Technical manual
Summary of Contents for Relion REG670
Page 1: ...Relion 670 series Generator protection REG670 2 0 IEC Technical manual ...
Page 2: ......
Page 44: ...38 ...
Page 58: ...52 ...
Page 80: ...74 ...
Page 106: ...100 ...
Page 482: ...476 ...
Page 548: ...542 ...
Page 570: ...564 ...
Page 600: ...594 ...
Page 608: ...602 ...
Page 630: ...624 ...
Page 862: ...856 ...
Page 1094: ...1088 ...
Page 1226: ...1220 ...
Page 1250: ...1244 ...
Page 1297: ...1291 ...