Model bond graph
Online surveillance of steam generator installation based on Bond Graphs

There are two basic types of online monitoring methods:

• those that use operating models based on the physical laws of the process;

• those based on historical or signal-based observations.

The latter methods (known as "model-free" or "external") do not require analytical models. They call on learning and pattern recognition procedures, or artificial intelligence, but must know a priori all operating states (normal and faulty): this is often unfeasible in real systems.

The performance of the first methods is highly dependent on the model used, but does not require training on the actual process. Even though their implementation...