There are now two contributions to system failure, the first being component failure overlapping component failure and the second being component failure overlapping component maintenance. There is a set of indices associated with each contribution. Since either contribution will cause system failure, they can be combined by using the principle associated with series system, i.e.,
. Consequently, the combined effect of both contributions gives
The principles and concept used to derive the expression which include maintenance for two parallel components or second order minimal cut sets can be further extended to three or more parallel components. This derivation is left to the reader although one point which must be considered in such a derivation will be discussed here. In the previous derivation it was assumed that maintenance would not be done if, by this action alone, it caused system failure. This constraint is also applicable to the third and higher order cases. In addition it must be decided if a maintenance outage will take place if another outage already exists. For instance, consider the failure sequence A followed by B followed by C.
Maintenance of C would never be done in this chronological sequence although maintenance of A would be considered. The main question is whether maintenance of B should or should not be considered, and if it is, whether it should only be considered if A is forced out of service or whether it should also be considered if A is on maintenance. All possibilities can be considered and the equations structured accordingly. It I not possible to generalize on this point: it depends greatly on operating policy.
There are now two contributions to system failure, the first being component failure overlapping component failure and the second being component failure overlapping component maintenance. There is a set of indices associated with each contribution. Since either contribution will cause system failure, they can be combined by using the principle associated with series system, i.e.,
. Consequently, the combined effect of both contributions gives
The principles and concept used to derive the expression which include maintenance for two parallel components or second order minimal cut sets can be further extended to three or more parallel components. This derivation is left to the reader although one point which must be considered in such a derivation will be discussed here. In the previous derivation it was assumed that maintenance would not be done if, by this action alone, it caused system failure. This constraint is also applicable to the third and higher order cases. In addition it must be decided if a maintenance outage will take place if another outage already exists. For instance, consider the failure sequence A followed by B followed by C.
Maintenance of C would never be done in this chronological sequence although maintenance of A would be considered. The main question is whether maintenance of B should or should not be considered, and if it is, whether it should only be considered if A is forced out of service or whether it should also be considered if A is on maintenance. All possibilities can be considered and the equations structured accordingly. It I not possible to generalize on this point: it depends greatly on operating policy.
การแปล กรุณารอสักครู่..