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

Section 4
Analog inputs
4.2.1.1

Example

Usually the A phase-to-ground voltage connected to the first VT channel number of the
transformer input module (TRM) is selected as the phase reference. The first VT channel number
depends on the type of transformer input module.
For a TRM with 6 current and 6 voltage inputs the first VT channel is 7. The setting
PhaseAngleRef=7 shall be used if the phase reference voltage is connected to that channel.
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 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 18.
Definition of direction
for directional functions
Reverse
Set parameter
CTStarPoint
Correct Setting is
"ToObject"
ANSI05000456 V2 EN-US
Figure 18: Internal convention of the directionality in the IED
With correct setting of the primary CT direction,
positive quantities always flowing towards the object and a direction defined as Forward always is
looking towards the object. The following examples show the principle.
4.2.2.1

Example 1

Two IEDs used for protection of two objects.
68
Forward
Protected Object
Line, transformer, etc
e.g. P, Q, I
Measured quantity is
positive when flowing
towards the object
18
Definition of direction
for directional functions
Forward Reverse
e.g. P, Q, I
Measured quantity is
positive when flowing
towards the object
Set parameter
CTStarPoint
Correct Setting is
"FromObject"
en05000456-2.vsd
CT_WyePoint set to FromObject or ToObject , a
1MRK 511 358-UUS A
SEMOD55055-11 v4
SEMOD55055-16 v5
SEMOD55055-23 v5
Application manual