"The level of stress experienced by an installation
Need more be written!?
There are, when it comes to electronics, two reasons for failure. The first is really out of the control of the power quality investigator and is something you should not beat yourself over the head about. Electronics do fail. Sadly, nothing is perfect and impurities in the wafers can lead to slow breakdown of the active portions of electronic components. These are, however, clearly indicated by the fact they are random and bear no relationship to their surroundings.
The second, and this applies to everything, is when components are stressed at or beyond their operating maximums. This, as said, applies to everything i.e. it even includes the wiring!
But it is not just individual components that cause a system to fail. Take a simple scenario of two consultants working on a new network to provide a new development with power. Each is told there may be a certain voltage drop under a given full load. The first specifies wiring and ensure the voltage will stay above the prerequisite. The second specifies the transformer and too ensures the voltage will stay above what is required. The system is commissioned and the voltage falls below the allowed minimum......
What the above has indicated is that power is never going to be perfect. The problem is, manufacturers believe it will never fluctuate. We all know they are in a dream world, and force us to live with the failures. These are the facts of life - power fluctuates, and some products don't like it. Until manufacturers make more resilient products, we're going to live with downtime.
Investigated now are the classic (and not so classic) symptoms, what they are, and how they manifest themselves.