Gi Optimization - ABB RELION 615 Series Protocol Manual

Section 3
Vendor-specific implementation
3.6.1
30
The IED includes some possibilities to fasten up and optimize the IEC 60870-5-103
communication. However, it is necessary to verify that these features are accepted by
the network and the IEC 60870-5-103 master used.
• Remove unnecessary Class 1 objects. Even if the IED can provide a lot of
valuable information, it is not feasible to send everything on slower serial links.
• Remove falling edge events for selected Class 1 objects.
• Serial communication speed can be increased up to 115.2 kbauds. However,
observe that all IED's on a multidrop link must support the same communication
speed.
• GI data optimization which means that not all data is sent as GI data in a GI cycle.

GI optimization

The master should initiate a GI always after the IED has reported a Class 1 event buffer
overflow. The IED starts then to send GI data through the Class 1 event buffer. As the
standard defines, new events always have higher send priority than GI data in the
IED's Class 1 buffer. The standard also defines that all data that are subject to GI is
sent by the IED.
Optimization of GI data is a non-standard feature. As default the Optimize GI n
parameter is set to "Standard behaviour", meaning that the GI cycle operates as
defined by the standard. GI optimization strives to send less data to the master through
the Class 1 report. The GI optimization in the IED is based on two facts:
• It is enough to send a certain Class 1 data once to the master after a GI initiation.
This could be either the GI data report or a spontaneously updated data report. In
either case the master has the true position of the Class 1 data in its database.
• The IED also remembers which specific Class 1 data objects changes that has
overflown. After the GI initiation only these marked Class 1 data objects are
reported through the GI cycle.
Table 12: GI optimization alternatives
Parameter value Description
Standard behaviour No optimization.
Skip spontaneous Enables the IED to not send GI data for those objects that already have been
spontaneously updated by the IED (that is, sent as Class 1 events) after the
initiation of a GI.
Only overflown Enables the IED to send only the Class 1 data that it knows have overflown in the
Class 1 buffer. The first GI cycle initiated after a master Reset CU or Reset FCB
does not use this feature, that is, the IED keeps track of that it actually has
reported a value at least once to the master since the last reset.
Combined Combines the two optimization features explained above.
1MRS759001 A
615 series
Communication Protocol Manual