ABB RELION REX640 - 4.5.5.5 Operation principle

4.5.5.4 Analog channel configuration
NSPTOV has one analog group input which must be properly configured.
Table 821: Analog inputs
Input Description
U3P Three-phase voltages
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 822: Special conditions
Condition Description
U3P connected to real measurements The function requires that any two voltage
channels are connected.
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.
4.5.5.5 Operation principle
The function can be enabled and disabled with the Operation setting. The
corresponding parameter values are "On" and "Off".
The operation of NSPTOV can be described using a module diagram. All the modules
in the diagram are explained in the next sections.
OPERATE
Level
detector
BLOCK
START
t
Timer
U3P
U
2
Blocking
logic
Figure 491: Functional module diagram
Level detector
The calculated negative-sequence voltage is compared to the set Start value setting.
If the value exceeds the set Start value , the level detector enables the timer.
Protection functions
1MRS759142 F
876 REX640
Technical Manual