4.5.6.2 Function block
Figure 492: Function block
4.5.6.3 Functionality
The positive-sequence undervoltage protection function PSPTUV is used to detect
positive-sequence undervoltage conditions. PSPTUV is used for the protection of
small power generation plants. The function helps in isolating an embedded plant
from a fault line when the fault current fed by the plant is too low to start an
overcurrent function but high enough to maintain the arc. Fast isolation of all the
fault current sources is necessary for a successful autoreclosure from the network-
end circuit breaker.
The function starts when the positive-sequence voltage drops below the set limit.
PSPTUV operates with the definite time (DT) characteristics.
The function contains a blocking functionality. It is possible to block function
outputs, the definite timer or the function itself.
4.5.6.4 Analog channel configuration
PSPTUV has one analog group input which must be properly configured.
Table 830: 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 831: Special conditions
Condition Description
U3P connected to real measurements The function can work with any two voltage
channels connected but it is recommended
to connect all three voltage channels.
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.
Protection functions
1MRS759142 F
880 REX640
Technical Manual
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