Function Block - ABB Relion 670 Series Technical Reference Manual

Section 2
Analog inputs
2.3
46
• Forward means direction into the object.
• Reverse means direction out from the object.
Definition of direction
for directional functions
Reverse Forward
e.g. P, Q, I
Measured quantity is
positive when flowing
towards the object
Set parameter
CT_WyePoint
Correct Setting is
"ToObject"
ANSI05000456 V1 EN
Figure 5: Internal convention of the directionality in the IED
If the settings of the primary CT is right, that is CTStarPoint set as FromObject or
ToObject according to the plant condition, then a positive quantity always flows
towards the protected object, and a Forward direction always looks towards the
protected object.
The settings of the IED is performed in primary values. The ratios of the main CTs and
VTs are therefore basic data for the IED. The user has to set the rated secondary and
primary currents and voltages of the CTs and VTs to provide the IED with their rated
ratios.
The CT and VT ratio and the name on respective channel is done under Main menu/
Hardware/Analog modules in the Parameter Settings tool.

Function block

The function blocks are not represented in the configuration tool. The
signals appear only in the SMT tool when a TRM is included in the
configuration with the function selector tool. In the SMT tool they can
be mapped to the desired virtual input (SMAI) of the IED and used
internally in the configuration.
Protected Object
Line, transformer, etc
Measured quantity is
positive when flowing
1MRK505222-UUS C
Definition of direction
for directional functions
Forward Reverse
e.g. P, Q, I
towards the object
Set parameter
CT_WyePoint
Correct Setting is
"FromObject"
en05000456_ansi.vsd
Technical reference manual