4.8.2.2 Function block
Figure 592: Function block
4.8.2.3 Functionality
The reverse power/directional overpower protection function DOPPDPR can be
used for generator protection against delivering an excessive power beyond the
generator's capacity to the grid, against the generator running like a motor, and
against the motor running like a generator and for protecting a motor which
consumes more reactive power due to loss of field. It can also be used in feeder
protection for indicating overload on the distribution system, to indicate that a
customer is supplying power into the grid and for protecting the transformer from
delivering an excessive load.
The function starts and operates when the measured power exceeds the set limit
and in a specified direction. The operate time characteristics are according to
definite time (DT).
This function contains a blocking functionality. It is possible to block the function
outputs, timer or the function itself.
4.8.2.4 Analog channel configuration
DOPPDPR has two analog group inputs which must be properly configured.
Table 999: Analog inputs
Input Description
I3P Three-phase currents
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 1000: Special conditions
Condition Description
U3P connected to real meas-
urements
The function can work with the corresponding one volt-
age channel connected if the
Measurement mode
is set to
"PhsAB", "PhsBC", "PhsCA", "PhsA", "PhsB" or "PhsC".
The function requires that at least two (the third voltage will
be derived) or all three voltage channels are connected for
the other measurement modes.
1MRS759142 F Protection functions
REX640
Technical Manual
1063
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