ABB RER670 - Page 53

Transformer and
Line protection
Transformer
Line
Setting of current input:
Set parameter
CTStarPoint with
Transformer as
reference object.
Correct setting is
"ToObject"
ReverseForward
Definition of direction
for directional
line functions
Setting of current input:
Set parameter
CTStarPoint with
Transformer as
reference object.
Correct setting is
"ToObject"
IED
IEC05000461 V2 EN-US
Figure 9: Example how to set CTStarPoint parameters in the IED
In this example, one IED includes both transformer and line protections and the
line protection uses the same CT as the transformer protection does. For both
current input channels, the CT direction is set with the transformer as reference
object. This means that the direction Forward for the line protection is towards the
transformer. To look towards the line, the direction of the directional functions of
the line protection must be set to Reverse. The direction Forward/Reverse is related
to the reference object that is the transformer in this case.
If the IED has sufficient number of analog current inputs, an alternative solution is
shown in Figure
10. The same currents are fed to two separate groups of inputs and
the line and transformer protection functions are configured to the different inputs.
The CT direction for the current channels to the line protection is set with the line
as reference object and the directional functions of the line protection shall be set to
Forwar
d to protect the line.
1MRK 506 375-UEN A Section 4
Analog inputs
Railway application RER670 2.2 IEC 47
Application manual