Siemens 6MD85, Manual

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Function Description
Logic
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Figure 8-26 Logic Diagram of the Current Phase-Rotation Supervision
The phase rotation is important for protection functions which process phase, loop, and directional informa-
tion. You can set the phase sequence with the
Phase sequence
parameter in the function block General of
the power-system data (see chapter 5.1 Power-System Data ).
To supervise the phase rotation, the device compares the measured phase sequence with the set phase
sequence. For abnormal phase sequences, the indication
Failure
is generated.
The connection of the currents to the device does not depend on the selected phase sequence. The connec-
tion diagrams are shown in the chapter
A Appendix .
Release Condition
The supervision of the current phase rotation is carried out when all measured phase currents are greater than
0.5 I
rated
.
Blocking of the Function
The following blockings reset the function completely:
•
Via the binary input signal
>Block function
from an external or internal source
•
Via a protection pickup
The pickup signal from a protection function blocks the indication
Failure
.
Delay failure indication
When the device detects an inverted phase sequence for the duration of the
Delay failure indication
,
the indication
Failure
is generated.
8.3.10.3
Supervision Functions
8.3 Supervision of the Secondary System
SIPROTEC 5, High-Voltage Bay Controller, Manual 967
C53000-G5040-C015-9, Edition 11.2017