CHARACTERISTICS
49
NV10B - Manual - 04 - 2022
Overvoltage - 59
Preface
Two operation thresholds, independently adjustable (
U
>,
U
>>) with adjustable delay (
t
U
>,
t
U
>>).
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 (
U
>) may be inhibited by start of the second threshold (
U
>>). .
Operation and settings
The fundamental frequency of input voltages are utilized.
Each of three voltages is compared with the setting values (
U
>,
U
>>).
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 overcomes the adjustable threshold (START); after expiry of the as-
sociated operate time (
t
U
>,
t
U
>>) a trip command is issued; if instead the voltages drops below the
threshold, the element is restored.
With
AND
selection, a start is issued when all the three voltages overcomes the adjustable thresh-
old; after expiry of the associated operate time (
t
U
>,
t
U
>>) a trip command is issued; if instead the
voltage drops below the threshold, the element is restored.
The first threshold (
U
>) may be programmed with definite or inverse time according the following
characteristic curve:
t
=0.5
t
U
>
inv
/ [(
U
/
U
>
inv
) - 1]
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 1.5 of the pickup value.
• Asymptotic reference value (minimum pickup value): 1.1
U
>
inv
• Minimum operate time: 0.1
s
• Range where the equation is valid: 1.1 ≤
U
/
U
>
inv
≤ 4
• If
U
>
inv
pickup ≥ 0.5
U
n
, the upper limit is 2
U
n
.
The first overvoltage 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) \
Overvoltage-59 \
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) \ Overvoltage-59 \
U
> Element \ Setpoints
menu and/or the
State
parameter
inside the
Set \ Profile A(or B) \ Overvoltage-59 \
U
>> Element \ Definite time
.
The operating logic (AND or OR) is adjustable inside the
Set \ Profile A(or B) \ Overvoltage-59 \ Com-
mon configuration
menu by means the
Logic59
parameter
;
the allowed settings are
OR
(at least
one voltage larger than threshold) or
And
(all three voltage must be larger than threshold).
The first threshold trip (
U
>) may be inhibited by start of the second threshold (
U
>>) by setting
ON
the U> Disabling by U>> start (
U>disbyU>>
) parameter available inside the
Set \ Profile A(or B) \
Overvoltage-59 \ U>> Element \ Setpoints
menu.
t-int-F59.ai
U
U
>>
t
U
>
t
U
>>
U
>
t
TRIP
General operation time characteristic for the overvoltage elements - 59
