Fault tree analysis (FTA) is used to demonstrate the events
or combination of events that can lead to insufficient SA at the
substation level. A detailed description of FTA is given in [24].
Fig. 18 shows the fault tree of the main sources of SA errors
at the substation level. As described in Section III, the main
causes of insufficient SA are divided into two main categories:
ICT failures and non-ICT failures. The probability of the top
event (insufficient SA) is given by the following equations:
(1)
(2)
(3)
PANTELI et al.: ASSESSING THE IMPACT OF INSUFFICIENT SITUATION AWARENESS ON POWER SYSTEM OPERATION 2975
Fig. 17. Substation layout with allocated IEDs, process bus, communications, and redundancy using IEC-61850.
TABLE V
LIST OF SUBSTATION COMPONENTS USING IEC-61850
Fig. 18. Fault tree of main sources of SA errors at the substation level.
The probability of events I4-I6 can be estimated if the probabilities
of the ICT failures at the substation are available. These
can be obtained directly from the component manufacturers or
from field or test data.