BlockSim Example: Default OFF unless SCT Overridden

Default OFF unless SCT overridden Example

Purposes

The purposes of this example is to illustrate the following options in SCT:

1. State Upon Repair: Default OFF unless SCT overridden
   
2. Activate a block if any item from these associated maintenance group(s) is restored
   
3. Deactivate a block if any item from these associated maintenance group(s) goes down
   
4. Activate a block if any item from these associated maintenance group(s) goes down
   
5. Deactivate a block if any item from these associated maintenance group(s) is restored
   

Description

Consider a system shown in Figure below:

Block A1 belongs to maintenance group A1.

Block A2 has state change triggers. Its inital state is ON, and the state upon repair is "Default OFF unless SCT overridden". If any item from maintenance group A1 goes down, then deactivate this bloc; if any item from the maintenance group A1 is restored, then activate this block.

Block B belong to maintenance group B.

Block C has state change triggers. Its intial state is OFF, and the state upon repair is "Default OFF unless SCT overridden". If any item from maintenance group B goes down, then activate this block; if any item from maintenance group B is restored, then deactivate this block.

All blocks A1, A2, B and C have Weibull distribution with Beta =1.5 and Eta = 100 for reliability. Block A1 and C have Weibull distribution with Beta = 1.5 and Eta = 100 for repair action. Block B has Weibull distribution with Beta =1.5 and Eta = 150 for repair action. Block A2 has Weibull distribution with Beta = 1.5 and Eta = 200 for repair action.  All blocks are as good as new after repair.

Block Up/Down plot

The system behavior for simulation of 820 hours durations (seed:23) is shown in Figure below and explained next.