69
NV10P - Manual - 01 - 2015
CHARACTERISTICS
Negative sequence overvoltage - 59V2
Preface
The protection has an adjustable threshold and defi nite time characteristic.
Enabling or disabling is provided by means ThySetter.
Operation and settings
The negative sequence voltage is calculated as:
U
2
=(
U
L1
+e
-j120°
·
U
L2
+e
+j120°
·
U
L3
)/3 where
U
L1
,
U
L2
and
U
L3
are the phase-ground for versions with in-
puts from electronic sensors, or
U
2
=(
U
12
+e
-j120°
·
U
23
+e
+j120°
·
U
31
)/3 where
U
12
,
U
23
e
U
31
are the voltages for versions with in-
puts from inductive VTs phase-to-phase, or by direct measurement of line voltages and with
e
-j120°
=-1/2-j√3/2, e
j120°
=-1/2+j√3/2.
For versions with voltage inputs from phase to earth measurement, the thresholds are expressed
in pu
E
n
, for versions with phase-to-phase inputs from inductive VTs or direct measurement, the
thresholds are expressed in pu
U
n
.
The negative sequence voltage is compared with the threshold (
U
2>def
).
A start is issued when the negative sequence voltage overcomes the adjustable threshold (START).
After expiry of the associated operate time (
t
U2
>) a trip command is issued; if instead the voltage
drops below the threshold, the element is restored.
The element can be enabled or disabled by setting
ON
or
OFF
the
State
parameter inside the
Set \
Profi le A(or B) \ Negative sequence overvoltage-59V2 \ U2> Element \ Defi nite time
menu.
The element can be disabled in the case of connection of the measuring inputs (TV or TV-I-NI) down-
stream of the Device Interface when the DI is open.
The threshold disabling is selected by setting
ON
the
U2>disbyCB_OPEN
parameter, inside the
Set \ Profi le A(or B) \ Negative sequence overvoltage-59V2 \ U2> Element \ Setpoints
menu.
Breaker failure (BF)
The negative sequence overvoltage element can produce the Breaker Failure output if the
U2>BF
parameter is set to
ON.
The parameter ia available inside the
Set \ Profi le A(or B) \ Negative sequence overvoltage - 59V2 \
U2> Element \ Setpoints
menu.
[1]
All the parameters can be set separately for
Profi le A
and
Profi le B
.
Logical block (Block1)
Note 1 The common settings concerning the Breaker failure protection are adjustable inside the
Breaker Failure - BF
menu.
U
2
U
2
>
def
t
t
U 2
>
def
TRIP
General operation time characteristic for the negative sequence overvoltage element - 59V2
U
2
U
2
>
def
t
t
U 2
>
def
TRIP
General operation time characteristic for the negative sequence overvoltage element - 59V2
all-597V2.ai
U2> Element
Start U2>
Trip U2>
t
U2> def
U
2
>
def
State
Block1
BLK1U2>
&
U2>BLK1
Start U2>
&
U2>BF
Trip U2>
&
U2>BF
U
2
General characteristic for the negative sequence overvoltage element - 59V2
all-597V2.ai
U2> Element
Start U2>
Trip U2>
t
U2> def
U
2
>
def
State
Block1
BLK1U2>
&
U2>BLK1
Start U2>
&
U2>BF
Trip U2>
&
U2>BF
U
2
General characteristic for the negative sequence overvoltage element - 59V2
