Power Quality Part Two – Measurement and Control

In Part One, we talked about power quality and some of the definitions 
outlined by the Institute of Electrical and Electronics Engineers (IEE).
 I hope you found that information useful.<br><br>Now that you know some
 of the issues that power quality can present, the next steps are: 
measuring power quality, and controlling it. Siemens

In Part One, we talked about power quality and some of the definitions outlined by the Institute of Electrical and Electronics Engineers (IEE). I hope you found that information useful.

Now that you know some of the issues that power quality can present, the next steps are: measuring power quality, and controlling it.

Measuring power quality is handled several ways. For the technician, portable handheld analyzers are commonly used. This gives on the spot readings in real time. Data loggers are used when records are needed for further analysis. While they don't give real-time readings, they can be used to discover trends. For example, some power quality issues are time-specific, occurring at certain hours daily.

I know of one instance where a power quality issue actually occured when an business started up their equipment. This caused problems in another building down the street. Trend analysis helped discover the problem. It was then possible to design and implement a solution, in this case, filters.

In other instances, power quality monitors are part of the permanent electrical installation at a facility. Continuous monitoring and tracking assures that processes are not interrupted and that quality control is possible. In data centers, this is crucial in preventing data loss.
However, knowing there is a problem is just half the equation. Armed with the data, you need to take steps to prevent damage or interruption caused by poor power quality.

Obviously, there is not a cookie cutter solution. The steps taken or additional equipment installed depend on the quality issue. For example, checking and repairing the grounding and bonding integrity of your system may be the answer.

Even improper wiring could be the needed repair. Loose, missing or improper connections at panels and machines can add to or be the cause of power quality issues.

For some applications, you might need to install power conditioning equipment. For example, transient voltage surge suppressors or TVSS are often the easiest and least expensive means to handle transient spikes.

A few other control measures are filters that reject higher than normal frequencies, isolation transformers that reduce electrical noise, or constant voltage transformers. CVTs ensure a nearly constant output voltage, even with large variations in the input voltage. These are often used when a very precise output voltage is needed.

In any case, measurement and control of power quality is important to reduce production issues and improve your company's product… and bottom line.


Photo courtesy of Siemens