x/EN AP/Na7
-32 MiCOM P74
• These algorithms offer flexibility to the operator not met in non-numeric conventional
systems
• The global substation topology is updated every 16ms
The above improve the overall function and discrimination of the protection scheme and
therefore reliability of the network.
6.3 Topology Communication
The peripheral units relay the information regarding their associated topological model to the
central unit. The central unit gathers the information from all attached peripheral units and
calculates the topological scheme for these as well as carrying out the calculations for the
system topology.
6.4 Topology data
Topology results are displayed in Central Unit and locally in Peripheral Units and can be
visualised in real time using the Dynamic Synoptic software.
For the Central Unit, zones included in each current node are displayed in Topology 1
column and current transformer (or Peripheral Unit) included in each current node are
displayed in Topology 2 column.
2 bars with 1 CT coupling example:
Node 1 = Zone 1; Node 2 = Zone 2
If the two zones are shunt by a feeder switches:
Node 1 = Zone 1 and Zone 2; Node 2 is then removed
2 bars with 2 CT coupling example:
Node 1 = Zone 1; Node 2 = Zone 2
A Node 3 is created when the coupling breaker is closed.
For the Peripheral Unit, link between current transformer and zones are displayed in
Topology column.
2 bars with 1 CT coupling example:
• The feeder PUs connected to Zone 1 are connected to Node 1
• The feeder PUs connected to Zone 2 are connected to Node 2 (if existing)
• The coupling PU is connected to the both nodes when the breaker is closed and to none
when the breaker is open
2 bars with 2 CT coupling example:
• The feeder PUs connected to Zone 1 are connected to Node 1
• The feeder PUs connected to Zone 2 are connected to Node 2 (if existing)
• The coupling PUs are connected to Node 3 and the appropriate node when the breaker
is closed and to none when the breaker is open
The bias and differential currents for the connected zone are displayed.
Note: If the topology scheme is equipped with a transfer bus outside the
protection zone, this link is never reported in Topology column
because the current transformer is connected to the feeder.
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