Example; Setting Of Current Channels; Example 3 - ABB RELION 670 SERIES Applications Manual

Section 4
Analog inputs
4.2.1.1
4.2.2
68

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.

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 6.
Definition of direction
for directional functions
Reverse Forward
e.g. P, Q, I
Measured quantity is
positive when flowing
towards the object
Set parameter
CTStarPoint
Correct Setting is
"ToObject"
ANSI05000456 V2 EN
Figure 6: 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 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.
6
Protected Object
Line, transformer, etc
Measured quantity is
positive when flowing
Line distance protection REL670 2.2 ANSI
1MRK 506 369-UUS -
Definition of direction
for directional functions
Forward Reverse
e.g. P, Q, I
towards the object
Set parameter
CTStarPoint
Correct Setting is
"FromObject"
en05000456-2.vsd
Application manual