Siemens 7SR51 - Application and Setting Notes

Application and Setting Notes
Parameter: Gn Element
•
Default setting: Disabled
This setting is used to allow the element to be switched on and off if it is not required. A separate setting
is provided for each element. These setting can be used to select the number of elements required.
Parameter Value Description
Disabled This element is off and is not available.
Enabled The element is available for use and can be parame-
terize.
Parameter: Gn Measurement
•
Default setting: RMS
Selects whether fundamental frequency RMS or the true RMS value of the measured currents used.
Parameter: Gn 50SOTF-n Setting
•
Default setting: 1 x I
n
(1 ⋅ I
rated
)
The setting of the parameter threshold depends on the respective application e.g. setting above load
curent and below fault current levels.
Parameter: Gn 50GSOTF-n Setting
•
Default setting: 0.5 x I
n
(0.5 ⋅ I
rated
)
The setting of the parameter threshold depends on the respective application e.g. setting below
minimum fault current levels.
Parameter: Gn Delay
•
Default setting: 0 ms
This is the time delay setting for the DTL element. This should be set to suit the individual application.
Parameter: Gn 81HB2 Inhibit
•
Default setting: No
High levels of inrush currents into reactive components such as transformers when they are switched can
result in operation of overcurrent elements. The inrush current can be detected by a high percentage of
second harmonic current content by the 81HBL2 element. This can be configured to inhibit the overcur-
rent element automatically by configuration of this setting.
Parameter Value
Description
No The element is not affected by operation of the
81HBL2 element.
Yes The element is inhibited by operation of the 81HBL2
element and automatically released when the 81HBL2
element resets.
5.16.4
Protection and Automation Functions
5.16 50SOTF Switch onto Fault
Reyrolle 7SR5, Overcurrent Protection Device, Device Manual 243
C53000-G7040-C014-1, Edition 11.2019