Line Application Example - ABB Relion REC670 Applications Manual

Section 7
Current protection
ActivationSOTF : This setting will select the signal to activate SOTF function; CB position
open/CB position closed/CB close command .
tSOTF : Time delay for operation of the SOTF function. The setting range is 0.000 - 60.000 s in
step of 0.001 s. The default setting is 0.100 s
StepForSOTF : If this parameter is set on the step 3 start signal will be used as current set level.
If set off step 2 start signal will be used as current set level.
t4U : Time interval when the SOTF function is active after breaker closing. The setting range is
0.000 - 60.000 s in step of 0.001 s. The default setting is 1.000 s.
ActUnderTime : Describes the mode to activate the sensitive undertime function. The function
can be activated by Circuit breaker position (change) or Circuit breaker command.
tUnderTime : Time delay for operation of the sensitive undertime function. The setting range is
0.000 - 60.000 s in step of 0.001 s. The default setting is 0.300 s
7.4.3.6

Line application example

The Four step residual overcurrent protection EF4PTOC can be used in different ways. Below is
described one application possibility to be used in meshed and effectively earthed systems.
The protection measures the residual current out on the protected line. The protection
function has a directional function where the polarizing voltage (zero-sequence voltage) is the
polarizing quantity.
The polarizing voltage and current can be internally generated when a three-phase set of
voltage transformers and current transformers are used.
IEC05000149 V1 EN-US
Figure 54: Connection of polarizing voltage from an open delta
The different steps can be described as follows.
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1MRK 511 358-UEN A
M15282-184 v7
Application manual