//Home/Methods/Example

 

Fault Tree
Event Tree

  

Example of methods for safety, reliability and availability analysis


The 415V diesel-backed bus example:

A 415V bus is connected to the external power grid (11kV) via a transformer and an isolator switch.
The 415V bus can also be powered by the diesel generator in case of a failure of the external grid. In such an event a connection switch, connecting the diesel generator to the 415V bus, needs to be activated.
Also, the isolator switch must disconnect the 415V bus and the diesel generator from the external grid. 

The thumbnail on the right (click to open) shows a diesel backed system for supplying power to the 415V bus. The bus is normally powered by the external grid (11 kV) via the transformer and the isolator switch.
In case of a black-out the bus can powered by the Diesel Generator via the connection switch.


We will now apply fault tree and event tree methods on this example system for analysing:

  1. The mean unavailability for the 415V bus
  2. The unconditional failure intensity of the 415V bus
  3. What sequences of events an external grid blackout could lead to, and the mean unavailability for the 415V bus based on these sequences of events.

The first step is to create a fault tree.

And then to create an event tree.



Back to top