Ieee std 1159-1995, ieee recommended Practice for Monitoring Electric Power Quality

8.5 Verifying data interpretation
Although this is the last subclause of this clause, it is by no means the least important. This clause has prima-
rily focused on taking clues, piecing them together, and arriving at a solution, or at least a very good guess.
The Þnal step in the process of data interpretation is to double check the solution (or guess) to see if it is,
indeed, the right one for the problem. This can be easily done through examining the following guidelines in
8.5.1 and 8.5.2 for post-monitoring.
An alternative veriÞcation is to utilize computer simulation tools. Many such programs are available that
allow a user to ÒtestÓ the validity of a proposed solution, especially if trial and error methods are risky or too
expensive.
8.5.1 Post-monitoring for veriÞcation
Once a solution has been implemented, post-monitoring determines the success of the solution. It attempts to
answer the following questions:
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Is the failing equipment now operating correctly?
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Is there a reduction or elimination of the disturbance(s) in question?
If the answer is ÒnoÓ to either of these questions, then further investigation is warranted. This is not to say
that the solution is wrong. Sometimes it may be, but often, solving one problem simply allows the next to
surface.
8.5.2 Post-monitoring for system interaction
Since the power system is just that, a system, changing one part of the system may affect other parts. It is
entirely possible that the ÒsolutionÓ to a problem may actually introduce another problem into the system. For
example, if the problem is that a vending machine injects transients into the power lines and disrupts a work-
station, the solution may be to plug the vending machine into a different receptacle. This works Þne for work-
station #1, but now workstation #2 has problems because the vending machine is now plugged into its
receptacle. Post-monitoring helps to determine if any other concerns have come up due to the implementation
of a solution.

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IEEE
Std 1159-1995
IEEE RECOMMENDED PRACTICE FOR
60