Siemens 7SR51 Device Manual page 297

Parameter: 1Ph/3Ph Power
•
Default setting: 3Ph
The relay measures the power components on each phase individually and provides the 3 phase sum
values. This setting is used to define whether the 55-n protection element operates from the 3 phase
value of power factor or from any of the individual phases. If it is required to provide a signal for all
phases beyond a threshold, the element should be set to 1 phase operation but the Under/Over
Operation should be reversed to suit with an inversion applied to the output signal in suitable logic.
Parameter: Dir. Control
•
Default setting: Non-Dir
The operating threshold can be applied as magnitude value only when set as Non-Dir or can be applied
to only leading or lagging power factor e.g. when set as Lagging the element will not operate during
leading power factor conditions. The element operates for both forward and reverse power flow.
[dw_7SR5_function55ApplicationAndSettingNotes, 1, en_US]
Parameter: Setting
•
Default setting: 0.85
This sets the operating threshold as a power factor magnitude value.
Parameter: Delay
•
Default setting: 1 s
This is the time delay setting for the DTL element. This should be set to suit the individual application.
Reyrolle 7SR5, Overcurrent Protection Device, Device Manual
C53000-G7040-C014-1, Edition 11.2019
Protection and Automation Functions
5.21 55 Power Factor
297