Template:Rotation: Difference between revisions

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==== BlockSim Solution  ====
==== BlockSim Solution  ====


The BlockSim model of this system is shown in the Figure below.  
The BlockSim model of this system is shown in the figure below.  


[[Image:Blocksim Example Rotation example.png|thumb|center|361px]]  
[[Image:Blocksim Example Rotation example.png|thumb|center|361px]]  
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*The failure distributions of all three blocks follow Weibull distribution with Beta = 1.5 and Eta = 1,000.  
*The failure distributions of all three blocks follow a Weibull distribution with Beta = 1.5 and Eta = 1,000.  
*The repair distribution of three blocks also follows Weibull distribution with Beta = 1.5 and Eta = 100.  
*The repair distributions of the three blocks follow a Weibull distribution with Beta = 1.5 and Eta = 100.  
*After repair, they are "as good as new".
*After repair, the blocks are "as good as new."




There are three maintenance groups, 2_A, 2_B and 2_C set as follows:
There are three maintenance groups, 2_A, 2_B and 2_C, set as follows:




*Block A belongs to maintenance group 2_A.  
*Block A belongs to maintenance group 2_A.  
**It has state change trigger.  
**It has a state change trigger.  
***The initial state is ON and the state upon repair is "Default Off Unless overridden".
***The initial state is ON and the state upon repair is "Default OFF unless SCT overridden."  
***If any item from maintenance group 2_C goes down, then activate this block.  
***If any item from maintenance group 2_C goes down, then activate this block.  


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*Block B belongs to maintenance group 2_B.  
*Block B belongs to maintenance group 2_B.  
**It has state change trigger.  
**It has a state change trigger.  
***The initial state is OFF and the state upon repair is "Default Off Unless overridden".
***The initial state is OFF and the state upon repair is "Default OFF unless SCT overridden."  
***If any item from maintenance group 2_A goes down, then activate this block.  
***If any item from maintenance group 2_A goes down, then activate this block.  




*Block C belongs to maintenance group 2_C.  
*Block C belongs to maintenance group 2_C.  
**It has state change trigger.  
**It has a state change trigger.  
***The initial state is OFF and the state upon repair is "Default Off Unless overridden".
***The initial state is OFF and the state upon repair is "Default OFF unless SCT overridden."  
***If any item from maintenance group 2_B goes down, then activate this block.  
***If any item from maintenance group 2_B goes down, then activate this block.  



Revision as of 22:20, 8 March 2012

Standby Rotation

Purpose

This example illustrates the use of state change triggers (SCT) in BlockSim Version 8 by using a simple standby configuration. Note that this example could also be done using the standby container functionality in BlockSim.

More specifically, the following settings are illustrated:

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

Statement

Assume three devices A, B and C in a standby redundancy (or only one unit is needed for system operation). The system begins with device A working. When device A fails, B is turned on and repair actions are initiated on A. When B fails, C is turned on and so forth.

BlockSim Solution

The BlockSim model of this system is shown in the figure below.

Blocksim Example Rotation example.png


  • The failure distributions of all three blocks follow a Weibull distribution with Beta = 1.5 and Eta = 1,000.
  • The repair distributions of the three blocks follow a Weibull distribution with Beta = 1.5 and Eta = 100.
  • After repair, the blocks are "as good as new."


There are three maintenance groups, 2_A, 2_B and 2_C, set as follows:


  • Block A belongs to maintenance group 2_A.
    • It has a state change trigger.
      • The initial state is ON and the state upon repair is "Default OFF unless SCT overridden."
      • If any item from maintenance group 2_C goes down, then activate this block.


  • Block B belongs to maintenance group 2_B.
    • It has a state change trigger.
      • The initial state is OFF and the state upon repair is "Default OFF unless SCT overridden."
      • If any item from maintenance group 2_A goes down, then activate this block.


  • Block C belongs to maintenance group 2_C.
    • It has a state change trigger.
      • The initial state is OFF and the state upon repair is "Default OFF unless SCT overridden."
      • If any item from maintenance group 2_B goes down, then activate this block.


  • All blocks A, B and C are as good as new after repair.

System Events

The system event log is shown Block Up/Down plot below, for a single run through the simulation algorithm and is as follows:

  1. At 73, Block A fails and activates Block B.
  2. At 183, Block B fails and activates Block C.
  3. At 215, Block B is done with repair. At this time, Block C is operating, according to setting, Block B is standby.
  4. At 238, Block A is done with repair. At this time, Block C is operating. Thus Block A is standby.
  5. At 349, Block C fails and activates Block A.
  6. At 396, Block A fails and activates Block B.
  7. At 398, Block C is done with repair. At this time, Block B is operating. Thus Block C is standby.
  8. At 432, Block A is done with repair. At this time, Block B is operating. Thus Block A is standby.
  9. At 506, Block B fails and activates Block C.
  10. At 515, Block B is done with repair and keeps standby because Block C is operating.
  11. At 536, Block C fails and active Block A.
  12. At 560, Block A fails and active Block B.
  13. At 575, Block B fails and put a request to active Block C. However, Block C is under repair at the time. Thus when Block C is done with repair at 606, the OFF setting is overwritten and it is operating immediately.
  14. At 661, Block C fails and put a request to active Block A. However, Block A is under repair at the time. Thus when Block A is done with repair at 699, the OFF setting is overwritten and it is operating immediately.
  15. Block B and Block C are done with repair at 682 and at 746 respectively. However, at these two time point, Block A is operating. Thus they are both standby upon repair according to settings.


Block Up Down plot for rotation example.png