Overexcitation Protection Oepvph; Identification; Function Block; Functionality - ABB RELION REX640 Technical Manual

1MRS759142 C
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REX640
Technical Manual

Overexcitation protection OEPVPH

Identification

Function description
Overexcitation protection

Function block

GUID-AD96FD45-4B1A-4A5F-90CD-7F208FF6182D V1 EN
Figure 435: Function block

Functionality

The overexcitation protection function OEPVPH is used to protect generators and
power transformers against an excessive flux density and saturation of the magnetic
core.
The function calculates the U/f ratio (volts/hertz) proportional to the excitation level
of the generator or transformer and compares this value to the setting limit. The
function starts when the excitation level exceeds the set limit and operates when the
set operating time has elapsed. The operating time characteristic can be selected to be
either definite time (DT) or overexcitation inverse definite minimum time
(overexcitation type IDMT).
This function contains a blocking functionality. It is possible to block the function
outputs, reset timer or the function itself.

Analog channel configuration

OEPVPH has two analog group inputs which all must be properly configured.
Table 764: Analog inputs
Input
I3P
U3P
See the preprocessing function blocks in this document for the
possible signal sources.
Protection functions
IEC 61850 IEC 60617
identification identification
OEPVPH U/f>
Description
Three-phase currents
Three-phase voltages
Section 4
ANSI/IEEE C37.2
device number
24
801