Operation Principle - ABB RELION REX640 Technical Manual

Section 4
Protection functions
4.1.3.5
350
There are a few special conditions which must be noted with the configuration.
Table 389: 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
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 Operation setting. The
corresponding parameter values are "on" and "off".
The operation of PHPVOC can be described by using a module diagram. All the
modules in the diagram are explained in the next sections.
I_A
I_B
I3P
I_C
ENA_MULT
U_AB
U_BC
U3P
U_CA
ENA_LOW_LIM
BLOCK
GUID-441BAD07-C771-4D40-84C3-E259204FC416 V1 EN
Figure 198: Functional module diagram
Effective start value calculator
The normal starting current above which the overcurrent protection starts is set
through the Start value setting. The Effective start value of the current may need to be
changed during certain conditions like magnetizing inrush or when the terminal
voltages drop due to a fault. Hence, the effective start value calculator module
dynamically calculates the effective start value above which the overcurrent
protection starts.
Four methods of calculating the effective start value are provided in PHPVOC. These
can be chosen with the Control mode setting to be either "Voltage control", "Input
control", "Volt & Input Ctrl" or "No Volt dependency".
Description
The function can work with any two voltage
channels connected but it is recommended to
connect all three voltage channels.
Phase
Level
selection
detector
logic
Effective
start value
calculator
1MRS759142 C
Timer
OPERATE
t
t
START
REX640
Technical Manual