ABB RELION REX640 Technical Manual page 1063

Protection and control

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1MRS759142 F

Function block

Figure 592: Function block

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.

Analog channel configuration

DOPPDPR has two analog group inputs which must be properly configured.

Table 999: Analog inputs

There are a few special conditions which must be noted with the configuration.

Table 1000: Special conditions

U3P connected to real meas-

Technical Manual

Three-phase currents

Three-phase voltages

See the preprocessing function blocks in this document for the possible

signal sources.

The function can work with the corresponding one volt-

age channel connected if the

"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.

Protection functions

Measurement mode is set to