The majority of power quality problems are relatively easy to troubleshoot, provided you ask a lot of questions and you don't lose focus.
Learning the art of acquiring and documenting information is a part of the overall troubleshooting process - especially for problems that are transient in nature and occur infrequently. A good example of this is when a main feeder breaker in a manufacturing plant trips unexpectedly. While this may only occur two or three times a year, the cost in lost production and materials can be in the thousands of dollars.
All power quality troubleshooting starts at the load. Because users or operators notice something has occurred at the load, this should be the beginning of the troubleshooting trail. The problem is while many people are technically inclined to perform the troubleshooting task, they may lack the interviewing skills needed to get to the source of the problem.
Having a troubleshooting document at hand (based on interviews) helps you to keep a record of the problems. You should use this document each time an event occurs. Over a period of time, this document will almost always lead you in the right direction.
Having a troubleshooting document is just as important as having the correct meter for the job. But just like any tool, you need to use it correctly to obtain maximum benefit. During the question and answer period, your job is to collect the most accurate data possible. While this may sound like a simple task, most people are not experienced in collecting data to troubleshoot a power quality problem. Creating a standard document to make certain you leave nothing unnoticed is a good start.
While filling out your power quality document, a valuable technique is to always ask the person you're interviewing: "How do you know?" For example, if the operator tells you the machine started acting funny around 2:00 p.m., you should ask: "How do you know it was 2:00 p.m.?" They will now have to give more thought to the question, and you will most likely get a more exact answer the second time. It's also important to interview several individuals about the same problem. You'll have less of a chance of overlooking a well-concealed culprit when interviewing many sources. Gathering as much past and present information about the event or occurrence as you can will help you discover all of the possibilities when troubleshooting a problem.
After finding and correcting the problem, you should always follow up. In some cases, you may have only reduced the frequency or severity of a problem, yet the problem still exists. A good follow-up is just as important as making the first discovery of the cause of a problem.
The goal of a PQ troubleshooter is to find the sources of a malfunction in the least amount of time with accuracy. This is pretty easy, if you think and act like a detective.
Sidebar: Three Ps of Troubleshooting
Past Information. Gather as much past information about the event or occurrence as you can. Our tendency is to focus on the immediate situation, but in troubleshooting it's important to connect the present situation to any and all past events. Using your detective skills, you will search out past events from many sources. This includes, installers, manufacturers, plant personnel, and operators.
Present information. It would seem that gathering present information is relatively easy, yet this is where much information is overlooked. Having an interviewing guide is important to gather even some of the smallest details, which are most often overlooked. It's common to have one small detail or fact about an event that becomes the thread connecting many other dissimilar pieces of information. You can see why details are so important at this stage.
Possibilities. The act of troubleshooting is connecting past with present information and coming up with possibilities. Many novice troubleshooters will jump at one or two possibilities too early and make them fit the facts. With experience comes the knowledge that you should leave all possibilities open until you exhaust all avenues.