System Interlocking; Description - Siemens SIPROTEC 7SJ61 Manual

Functions
2.18 Breaker Control
2.18.4

System Interlocking

System interlocking is executed by the user-defined logic (CFC).

2.18.4.1 Description

System interlocking checks in a SICAM/SIPROTEC 4 system are usually categorized as follows:
• System interlocking relies on the system data base in the substation or central control system.
• Bay interlocking relies on the object data base (feedbacks) of the bay unit.
• Cross-bay interlocking via GOOSE messages directly between bay units and protection relays (with
IEC61850: GOOSE information exchange will be accomplished via EN100-module)
The extent of the interlocking checks is determined by the configuration of the relay. For more information on
GOOSE, please refer to the SIPROTEC 4 System Description /1/.
Switching objects that require system interlocking in a central control system are assigned to a specific param-
eter inside the bay unit (via configuration matrix).
For all commands, operation with interlocking (normal mode) or without interlocking (Interlocking OFF) can be
selected:
• for local commands, by reconfiguration via password prompt,
• for automatic commands, via command processing by CFC using non-interlocking detection,
• for local / remote commands, using an additional interlocking disable command, via Profibus.
Interlocked / Non-interlocked Switching
The configurable command checks in the SIPROTEC 4 devices are also called "standard interlocking". These
checks can be activated via DIGSI (interlocked switching/tagging) or deactivated (non-interlocked).
Deactivated interlock switching means that the configured interlocking conditions are not checked in the relay.
Interlocked switching means that all configured interlocking conditions are checked within the command pro-
cessing. If a condition is not fulfilled, the command will be rejected by a message with a minus added to it (e.g.
"CO–"), immediately followed by a message.
The following table shows the possible types of commands in a switching device and their corresponding mes-
sages. For the device the messages designated with *) are displayed in the event logs, for DIGSI they appear
in spontaneous messages.
Control issued
Manual tagging (positive / negative)
Information state command, Input blocking
Output Blocking
Cancel command
The "plus" appearing in the message is a confirmation of the command execution. The command execution
was positive as expected The minus sign means a negative confirmation, the command was rejected. Possible
command feedbacks and their causes are dealt with in the SIPROTEC^ 4 System Description. The following
figure shows operational indications relating to command execution and operation response information for
successful switching of the circuit breaker.
The check of interlockings can be programmed separately for all switching devices and tags that were set with
a tagging command. Other internal control actions, such as manual entry or cancel are not tested, i.e. carried
out independent of the interlocking.
248
Type of Command Control
Switching CO
Manual tagging MT
Input blocking ST
Output blocking ST
Cancel CA
C53000-G1140-C210-1, Release date 02.2008
Cause Message
CO+/–
MT+/–
ST+/– *)
ST+/– *)
CA+/–
SIPROTEC, 7SJ61, Manual