ABB RELION REX640 Technical Manual page 915

1MRS759142 F
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.
4.5.10.5 Operation principle
The function can be enabled and disabled with the
corresponding parameter values are "On" and "Off".
The operation of PHVPTOV can be described with a module diagram. All the
modules in the diagram are explained in the next sections.
U3P
INITIALIZE
RESET
BLOCK
Figure 512: Functional module diagram
Average calculation
The module calculates the average voltage magnitude variation for each of the three
input phase voltages. The calculation is done in three successive aggregations.
• 10/12-cycle voltage input samples are aggregated to calculate the 10/12-cycle
RMS voltage.
• 10/12-cycle RMS voltages are aggregated over a time period of T
refresh value.
• Refresh values are aggregated over a time period T
voltage magnitude.
The
phase voltages for protection.
Calculation of 10/12-cycle RMS voltage
The 10/12-cycle RMS voltage is calculated for each of the three input voltages by
applying the standard RMS formula using the voltage samples over a range of 0.2
s. Depending on the
earth or phase-to-phase voltage samples.
Calculation of RMS refresh voltage
The RMS refresh voltage is calculated by aggregating the U
voltage over a time period of T
Time interval .
REX640
Technical Manual
U_A_AB
U_B_BC
Average
U_C_CA
calculation
Blocking
logic
Voltage selection setting is used for selecting phase-to-earth or phase-to-
Voltage selection setting, voltage samples are either phase-to-
Phase
Level
selection
detector
logic
. The time period T
refresh
Protection functions
Operation setting. The
Timer
t
refresh
to get the average RMS
average
/ U
10cycles 12cycles
depends on the setting
refresh
OPERATE
START
to get the
RMS
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