ABB RELION REX640 Technical Manual page 1079

Protection and control

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1MRS759142 F

Function block

Figure 602: Function block

Functionality

The under power factor function MPUPF is used to provide out-of-step and loss of,

or under excitation protection for small synchronous motors and generators. The

function calculates the power factor and uses a threshold of under power factor as

an indication of an out-of-step and/or loss of excitation condition.

In addition, the function can be applied as a power factor controller.

The function contains a blocking functionality. It is possible to block function

outputs, timers or the function itself.

Analog channel configuration

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

Table 1018: Analog inputs

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

Table 1019: Special conditions

U3P connected to real meas-

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.

Operation principle

The function can be enabled and disabled with the

corresponding parameter values are "on" and "off".

Technical Manual

Three-phase currents

Three-phase voltages

See the preprocessing function blocks in this document for the possible

signal sources.

The function requires that any two voltage channels are con-

Protection functions

Operation setting. The