Parameter: 1Ph/3Ph Power
•
Default setting: 3Ph
The setting can be applied as a single phase or 3 phase power level. The nameplate rating of 3 phase
plant (e.g. motors and transformers) is usually the 3 phase rating.
Parameter: Power (Measurement)
•
Default setting: Real
This parameter is used to specify the measured power type real power (P), reactive power (Q) or apparent
power (S).
Parameter: Dir.Control
•
Default setting: Non-Dir
When set to Non-Dir the scalar value of the measured power is compared to the setting value.
Forward operation refers to positive measured value of:
V ⋅ I ⋅ cos θ (real power)
V ⋅ I ⋅ sin θ (reactive power)
V ⋅ I (apparent power)
Reverse operation refers to negative measured value of the above.
Parameter: Setting
•
Default setting: 1 x S
n
(1 ⋅ S
rated
)
The setting is input as a multiple of the rated/nominal secondary apparent power (S
rated
) since all power
measurements include the measurement of V ⋅ I.
rated (nominal) 3 phase power =
Rated/nominal current and voltage values are defined in the CT/VT config menu.
Parameter: Delay
•
Default setting: 1 s
The function has a definite time delayed operate characteristic.
Parameter: UC Guard
•
Default setting: Off
Parameter: UC Guard Setting
•
Default setting: 0.2 x I
n
(0.2 ⋅ I
rated
)
Power measuring elements can be blocked where all phase currents fall below this setting.
Parameter: VTS Inhibit
•
Default setting: No
Settings Example
Directional power protection is often applied to motor or embedded generator applications to detect loss of
load, loss of generation or back feeds. For these applications, Real power may be a more appropriate oper-
ating quantity.
Protection and Automation Functions
5.4 32 Power Protection
Reyrolle 7SR5, Overcurrent Protection Device, Device Manual 165
C53000-G7040-C014-1, Edition 11.2019
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