See the preprocessing function blocks in this document for the possible
signal sources.
There are a few special conditions which must be noted with the configuration.
Table 556: Special conditions
Condition
Description
URES calculated
The function requires that all three voltage
channels are connected for calculating the re-
sidual voltage. Setting
VT connection
must
be "Wye" in that particular UTVTR.
Improper analog channel configuration causes a validation error if the analog
channels are not completely configured or they do not match with certain settings.
For troubleshooting, check the contents of this chapter and also the preprocessing
blocks in this document. The configuration can be written to the protection relay
once the mismatch is corrected.
4.2.3.5
Operation principle
The function can be enabled and disabled with the
Operation setting. The
corresponding parameter values are "On" and "Off".
The operation of INTRPTEF can be described with a module diagram. All the
modules in the diagram are explained in the next sections.
BLK_EF
OPERATE
BLOCK
START
Timer 2
t
Timer 1
Transient
detector
Fault
indication
logic
Level
detector
IRES
URES
Io
Uo
Figure 273: Functional module diagram
Level detector
The Level detector module is used only when selected
Operation mode is "Transient
EF". The module compares the measured residual voltage to the set
Voltage start
value. If the measured value exceeds the set
Voltage start value, the module reports
the exceeding of the value to the Fault indication logic.
Transient detector
The Transient detector module is used for detecting transients in the residual
current and residual voltage signals.
The transient detection is supervised with a settable current threshold. With
a special filtering technique, the setting
Min operate current is based on the
1MRS759142 F
Protection functions
REX640
Technical Manual
483