Application And Setting Notes - Siemens 7SR51 Device Manual

Protection and Automation Functions
5.18 51G Time-Delayed Earth Fault – Measured

Application and Setting Notes

5.18.4
Parameter: 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
Disabled
Enabled
Parameter: Measurement
•
Default setting: RMS
Selects whether fundamental frequency RMS or the true RMS value of the measured currents used.
Parameter Value
RMS
Fundamental
Parameter: Dir. Control
•
Default setting: Non-Dir
This setting is used to define whether the element will operate for earth faults detected in the Forward
or Reverse direction based on the 67G directional element decision or for any earth fault regardless of
the 67G direction. This allows the earth fault protection to have different current and time settings for
forward, reverse and non-directional faults by using three 67G function elements.
This parameter is not provided in devices that do not have voltage inputs or for current inputs that are
not polarized by the voltage inputs.
Parameter Value
Non-Dir
Forward
Reverse
270
Description
This element is switched out and is not available.
The element is available for use and can be parame-
terized.
Description
Select this method of measurement if it is required to
consider the effects of harmonic currents. This
method may be required if there are significant
harmonic content such as at capacitor banks or filter
networks. This method is required for correct grading
with fuses or electromechanical overcurrent relays.
This method is used if harmonic components are not
to be considered in the current evaluation. This
method may be required for correct grading with
devices which do not provide true RMS measurement.
This method may be preferred for unbalance type
protection where the unbalance applies at funda-
mental frequency and the risk of errors in transient
response measurement can be avoided.
Description
Select this setting if the element is to operate regard-
less of the current direction or presence of voltage.
Select this setting if the element is to operate only in
a forward direction
Select this setting if the element is to operate only in
a reverse direction
Reyrolle 7SR5, Overcurrent Protection Device, Device Manual
C53000-G7040-C014-1, Edition 11.2019