FUNCTION CHARACTERISTICS
80
NA30 - Manual - 04 - 2022
Residual overvoltage - 59N
Preface
Two operation thresholds, independently adjustable (U
E
>, U
E
>>) with adjustable delay (t
UE
>, t
UE
>>).
The first one (U
E
>) 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
E
>) may be inhibited by start of the second threshold (U
E
>>).
Operation and settings
The residual voltage (U
E
) is compared with the setting values (U
E
>, U
E
>>); a start is issued when the
residual voltage overcomes the adjustable threshold (START); after expiry of the associated operate
time (t
UE
>, t
UE
>>) a trip command is issued; if instead the voltage drops below the threshold, the
element is restored.
The first threshold (U
E
>) may be programmed with definite or inverse time according the following
characteristic curve:
t=0.5 t
UE
> / [(U
E
/U
E
>
inv
) - 1] or
Where:
U
E
: measured residual voltage
t: operate time
U
E
>
inv
: threshold setting
t
UE>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
E
>
inv
• Minimum operate time: 0.1 s
• Range where the equation is valid: 1.1 ≤ U
E
/U
E
>
inv
≤ 4
• If U
E
>
inv
pickup ≥ 0.5 U
En
, the upper limit is 2 U
En
.
The first residual overvoltage element can be programmed with definite or inverse time character-
istic by setting the UE> Curve parameter (DEFINITE, INVERSE) available inside the Set \ Profile
A(or B) \ Residual overvoltage-59N \ UE> Element \ Setpoints menu.
Each element can be enabled or disabled by setting ON or OFF the UE> Enable parameter inside
the Set \ Profile A(or B) \ Residual overvoltage-59N \ UE> Element \ Setpoints menu and/or the State
parameter inside the Set \ Profile A(or B) \ Residual overvoltage-59N \ UE>> Element \ Definite time.
For both elements, a block of the U
E
> and U
E
>> threshold may be select when the 74VT function is
active (external). The blocking enabling parameters 74VText59N is available inside the Set \ Pro-
file A(or B) \ Residual overvoltage-59N \ Common configuration menu.
[1]
The first threshold trip (U
E
>) may be inhibited by start of the second threshold (U
E
>>) by setting ON
the UE> Disabling by UE>> start (UE>disbyUE>>) parameter available inside the Set \ Profile A(or
B) \ Residual overvoltage-59N \ UE>> Element \ Setpoints menu.
Note 1 The operating time must be adjusted to a greater value than the 74VT activation time (internal or binary input)
t-int-F59N.ai
U
E
U
E
>>
t
UE
>
t
UE
>>
U
E
>
t
TRIP
General operation time characteristic for the residual overvoltage elements - 59N
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