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7.1.3.4
Voltage instability mitigation
This setting is very much dependent on the power system characteristics, and thorough
studies have to be made to find the suitable levels.
7.1.3.5
Backup protection for power system faults
The setting must be below the lowest occurring "normal" voltage and above the highest
occurring voltage during the fault conditions under consideration.
7.1.3.6
Settings for Two step undervoltage protection
The following settings can be done for two step undervoltage protection (UV2PTUV ,27).
GlobalBaseSel
: Selects the global base value group used by the function to define (
IBase
),
(
VBase
) and (
SBase
).
ConnType:
Sets whether the measurement shall be phase-to-ground fundamental value,
phase-to-phase fundamental value, phase-to-ground RMS value or phase-to-phase RMS
value.
Operation
:
Disabled/Enabled
.
UV2PTUV (27) measures selectively phase-to-ground voltages, or phase-to-phase
voltage chosen by the setting
ConnType
.
This means operation for phase-to-ground voltage if:
(%)
(
)
3
<
×
V
VBase kV
EQUATION1711 V1 EN
(Equation 81)
and operation for phase-to-phase voltage if:
Vpickup
(%) VBase(kV)
<
×
EQUATION1991-ANSI V1 EN
(Equation 82)
Characteristic1
: This parameter gives the type of time delay to be used for step 1. The
setting can be.
Definite time/Inverse Curve A/Inverse Curve B
. The choice is highly
dependent of the protection application.
OpModen
: This parameter describes how many of the three measured voltages that should
be below the set level to give operation for step
n
(
n
=step 1 and 2). The setting can be
1
out of 3
,
2 out of 3
or
3 out of 3
. It is sufficient that one phase voltage is low to give
1MRK 511 286-UUS A
Section 7
Voltage protection
153
Application manual
Summary of Contents for REC650 ANSI
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Page 66: ...Section 3 1MRK 511 286 UUS A REC650 setting examples 60 Application manual...
Page 71: ...IED IED ANSI05000460 V2 EN 1MRK 511 286 UUS A Section 4 Analog inputs 65 Application manual...
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