[sj6x-ueb-einph-kesselschut-020926-rei, 1, en_US]
Figure 2-45
Principle of tank-leakage protection
Setting Notes
General
Single-phase time overcurrent protection can be set
ON
or
OFF
at address 2701
50 1Ph
.
The settings are based on the particular application.
The setting ranges depend on whether the current measuring input is a sensitive or a normal input trans-
former (see also “Ordering Information” in the Appendix).
In case of a normal input transformer, set the pickup value for
50 1Ph-2 PICKUP
in address 2702, the
pickup value for
50 1Ph-1 PICKUP
in address 2705. If only one element is required, set the one not
required to ∞.
In case of a sensitive input transformer, set the pickup value for
50 1Ph-2 PICKUP
in address 2703, the
pickup value for
50 1Ph-1 PICKUP
in address 2706. If only one element is required, set the one not
required to ∞.
A trip time delay can be set in address 2704
50 1Ph-2 DELAY
for the 50-2 element and for the 50-1 element
in address 2707
50 1Ph-1 DELAY
. With setting 0 s no delay takes place.
The selected times are additional time delays and do not include the operating time (measuring time, etc.) of
the elements. The delay can also be set to ∞; the corresponding element will then not trip after pickup, but
the pickup is reported.
Special notes are given in the following for the use as high-impedance unit protection and tank leakage
protection.
Application as High-impedance Protection
The application as high-impedance protection requires that neutral point current detection is possible in the
system in addition to phase current detection (see example in
). Furthermore, a sensitive input
transformer must be available at device input
Ι
N
/
Ι
NS
. In this case, only the pickup value for single-phase over-
current protection is set at the 7SJ62/64 device for the current at input
Ι
N
/
Ι
NS
.
The entire function of high-impedance protection is, however, dependent on the interaction of current trans-
former characteristics, external resistor R and voltage across R. The following section gives information on this
topic.
Current Transformer Data for High-impedance Protection
All current transformers must have an identical transformation ratio and nearly equal knee-point voltage. This
is usually the case if they are of equal design and identical rated data. The knee-point voltage can be approxi-
mately calculated from the rated data of a CT as follows:
2.5.4
Functions
2.5 Single-Phase Overcurrent Protection
SIPROTEC 4, 7SJ62/64, Manual
121
C53000-G1140-C207-8, Edition 08.2016
Summary of Contents for SIPROTEC 4
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