Thytronic XMR-V 4V User Manual

96
FUNCTION CHARACTERISTICS
— Undervoltage - 27
Preface
Two operation thresholds, independently adjustable with adjustable delay.
The first one may be programmed with definite or inverse time, while the second threshold operates
with definite time characteristic.
Each threshold may be separately enabled or disabled.
The first threshold trip may be inhibited by start of the second threshold.
Operation and settings
The fundamental frequency of a selectable voltages, phase to ground (U
L1
, U
L2
, U
L3
) or phase-to-pha-
se voltages (U
12
, U
23
, U
31
) are utilized:
Each of three voltages compared with the setting values. The start and trip logic may be selected
OR or AND.
With OR selection, a start is issued when at least one of the three voltages goes down the adjustable
threshold (START); with AND selection, a start is issued when all the three voltages go down the
adjustable threshold.
After expiry of the associated operate time a trip command is issued; if instead the voltages exceed
the threshold, the element is restored.
The first threshold may be programmed with definite or inverse time according the following cha-
racteristic curve:
t=0.75 t
U<inv
/ [1-(U/U<
inv
)]
Where:
t
: operate time
U<
inv
: threshold setting
t
U<inv
: operate time setting
For the inverse time characteristic, following data applies:
• The operate time setting is referred to an input voltage equal to 1/4 of the pickup value.
• Asymptotic reference value (minimum pickup value): 0.9 U<
• Minimum operate time: 0.1 s
• Range where the equation is valid: 0 ≤ U/U<
inv
≤ 0.9
The first undervoltage element can be programmed with definite or inverse time characteristic by
setting the U<Curve parameter (
DEFINITE,INVERSE) available inside the Set \ Profile A (or B) \
Undervoltage-27 \ U< Element \ Setpoints menu.
Each element can be enabled or disabled by setting ON or OFF the
U<Enable parameter inside
the Set \ Profile A (or B) \ Undervoltage-27 \ U< Element \ Setpoints menu and/or the State parame-
ter inside the Set\Profile A (or B) \ Undervoltage-27 \ U<< Element \ Definite time.
The voltage measurement type (Phase-to-phase or phase-to-neutral) and the operating logic (AND
or OR), is adjustable inside the Set \ Profile A (or B) \ Undervoltage-27 \ Common configuration menu
by means the
Utype27parameter; the allowed setting are Uph-ph (phase-to-phase) or Uph-n
(phase-to-neutral).
The corresponding unit are p.u. U
n
for Uph-ph setting and p.u. E
n
for Uph-n setting.
U
12
=|U
L1
-U
L2
|
U
23
=|U
L2
-U
L3
|
U
31
=|U
L2
-U
L1
|
General operation time characteristic curve for the undervoltage elements - 27
U
U<< U<
0.9U<
t
U
<<
t
t
U
<
TRIP
XMR-D EQUIPMENT MANUAL
Ed. 2.9 - 02/2021

Thytronic XMR-V 4V Specifications

General

Brand	Thytronic
Model	XMR-V 4V
Category	Protection Device
Language	English