Hidden failures in CBTMs can cause the trip of intact
equipment following system disturbances, which reduces the
system reliability level. In this section, an approach of hidden
ailure effects analysis for each system substation is proposed
o obtain possible hidden failure outages following any initial
aults. The proposed hidden failure effects analysis procedure
s illustrated by the example substation shown in Figure 1.
We assume that the substation is under state 3 as enumerated
n Table 1. In state 3, the trip mechanism of circuit breaker 2
(CB2) has hidden failure that can cause CB2 fail to open. If an
nitial fault Ft occurs on transmission line LI as shown in
Figure 1, circuit breakers
1 and 2 should open to isolate the
faulty circuit LI accordingly. Since CB2 fail to open due to its
hidden failure, circuit breaker 3 (CB3) that is adjacent to CB2
ill open and then cause the outage of intact component
transmission line L2 following the initial fault on transmission
ine LI.