Function Block - ABB RELION REX640 Technical Manual

Section 4
Protection functions
4.8.3.2
4.8.3.3
4.8.3.4
970

Function block

GUID-38A8793B-4FAD-45CA-B71C-1F32A6155727 V1 EN
Figure 525: 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 907: Analog inputs
Input
I3P
U3P
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 908: Special conditions
Condition
U3P connected to real measurements
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
Description
Three-phase currents
Three-phase voltages
Description
The function can work with any two phase voltage
channels connected but it is recommended to
connect all three voltage channels.
1MRS759142 C
REX640
Technical Manual