Functions
2.15 Monitoring Functions
SIPROTEC, 7SD610, Manual
C53000-G1176-C145-6, Release date 02.2011
210
2.15.1.4 Monitoring the Phase Angle of the Positive Sequence Power
This monitoring function allows determining the direction of power flow. You can monitor the phase angle of the
complex power, and generate an indication when the power phasor is inside a settable segment.
One example of this application is the indication of capacitive reactive power. The monitoring indication can
then be used to control the overvoltage protection function. For this purpose, two angles must be set, as shown
in Figure 2-92. In this example, ϕA = 200° and ϕB = 340° has been set.
If the measured phase angle Ï•(S
1
) of the positive sequence power is within the area of the P-Q plane delimited
by the angles ϕA and ϕB, the indication „ϕ(PQ Pos. Seq.)“ (No. 130) is output. The angles ϕA and ϕB can
be freely set in the range between 0° and 359°. The area starts at ϕA and extends in a mathematically positive
sense as far as the angle ϕB. A hysteresis of 2° is provided to prevent erroneous indications which might
emerge at the threshold limits.
Figure 2-92 Characteristic of the Positive Sequence System Phase Angle Monitoring
The monitoring function can also be used for the display of negative active power. In this case the areas must
be defined as shown in Figure 2-93.
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