ABB RELION REX640 Technical Manual page 1072

Protection and control

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Protection functions

Directional reactive power undervoltage protection

DQPTUV (ANSI 32Q,27)

Identification

Function description

Directional reactive power under-

voltage protection

Function block

Figure 598: Function block

Functionality

The directional reactive power undervoltage protection function DQPTUV is used at

the grid connection point of distributed power generating units as stipulated by

various grid codes to prevent voltage collapse of the grid due to network faults.

DQPTUV measures phase voltages and current at the grid connection point. The

generating facility is disconnected from the network with a specific time delay if all

phase voltages decrease and remain at or below the specified limit and if reactive

power is simultaneously consumed (that is, under-excitation operation).

DQPTUV contains a blocking functionality to block function outputs, timer or the

function itself.

Analog channel configuration

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

Table 1009: Analog inputs

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

Three-phase currents

Three-phase voltages

See the preprocessing function blocks in this document for the possible

signal sources.

identification

1MRS759142 F

ANSI/IEEE C37.2

device number

Technical Manual