4.5.3.2
Function block
Figure 486: Function block
4.5.3.3
Functionality
The residual overvoltage protection function ROVPTOV is used in distribution
networks where the residual overvoltage can reach non-acceptable levels in, for
example, high impedance earthing.
The function starts when the residual voltage exceeds the set limit. ROVPTOV
operates with the definite time (DT) characteristic.
The function contains a blocking functionality. It is possible to block function
outputs, the definite timer or the function itself.
4.5.3.4
Analog channel configuration
ROVPTOV has one analog group input which must be properly configured.
Table 803: Analog inputs
Input
Description
URES
Residual voltage (measured or calculated)
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 804: Special conditions
Condition
Description
URES calculated
The function requires that all three voltage
channels are connected to calculate residu-
al 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.
1MRS759142 F
Protection functions
REX640
Technical Manual
867