ABB REL650 series, Applications Manual

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A positive value of current, power, and so on (forward) means that the quantity has a
direction towards the object. - A negative value of current, power, and so on (reverse)
means a direction away from the object. See figure
35 .
Protected Object
Line, transformer, etc
Forward Reverse
Definition of direction
for directional functions
Measured quantity is
positive when flowing
towards the object
e.g. P, Q, I
Reverse Forward
Definition of direction
for directional functions
e.g. P, Q, I
Measured quantity is
positive when flowing
towards the object
Set parameter
CTStarPoint
Correct Setting is
"ToObject"
Set parameter
CTStarPoint
Correct Setting is
"FromObject"
en05000456-2.vsd
ANSI05000456 V2 EN
Figure 35: Internal convention of the directionality in the IED
With correct setting of the primary CT direction, CT_WyePoint set to FromObject or
ToObject , a positive quantity always flows towards the protected object and a direction
defined as Forward is always looking towards the protected object. The following
examples show the principle.
4.2.3.1 Example 1
Two IEDs used for protection of two objects.
1MRK 506 334-UUS A
Section 4
Analog inputs
91
Application manual