Setting Of Current Channels; Example 1 - Hitachi Relion 670 Series Applications Manual

Section 4
Analog inputs
4.2.2

Setting of current channels

The direction of a current to the IED is depending on the connection of the CT. Unless indicated
otherwise, the main CTs are supposed to be Wye (star) connected and can be connected with the
grounding point to the object or from the object. This information must be set in the IED. The convention
of the directionality is defined as follows: A positive value of current, power, and so on means that the
quantity has the direction into the object and a negative value means direction out from the object. For
directional functions the direction into the object is defined as Forward and the direction out from the
object is defined as Reverse. See Figure
A positive value of current, power, and so on (forward) means that the quantity flows towards the object.
A negative value of current, power, and so on (reverse) means that the quantity flows away from the
object. See Figure 5.
Definition of direction
for directional functions
Reverse
Set parameter
CTStarPoint
Correct Setting is
"ToObject"
ANSI05000456 V2 EN-US
Figure 5:
With correct setting of the primary CT direction, CT_WyePoint set to FromObject or ToObject, a positive
quantities always flowing towards the protected object and a direction defined as Forward always is
looking towards the protected object. The following examples show the principle.
4.2.2.1

Example 1

Two IEDs used for protection of two objects.
42
Forward
Protected Object
Line, transformer, etc
e.g. P, Q, I
Measured quantity is
positive when flowing
towards the object
Internal convention of the directionality in the IED
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5
Definition of direction
for directional functions
Forward
e.g. P, Q, I
Measured quantity is
positive when flowing
towards the object
1MRK511407-UUS Rev. N
Reverse
Set parameter
CTStarPoint
Correct Setting is
"FromObject"
en05000456-2.vsd
Phasor measurement unit RES670
Application manual
SEMOD55055-16 v6
SEMOD55055-23 v6