Audit On-Site

On-site visits should be structured for the power quality investigator to gather all of the information necessary to make a proper diagnosis and enable appropriate and cost-effective solutions to be recommended. There are generally two types of power quality problems requiring resolution, they are Steady-State problems and Transient problems.

Steady-state Problems

Steady-state problems are encountered most often. They are characterized either by the continuous presence of problem symptoms, or symptoms that recur on a frequent basis. They are primarily found in residential, light commercial, and industrial applications. A small retail shop or professional office is a good example. Routinely using sophisticated equipment such as computers, scanners, and copy machines, the customer can usually explain the problem or its symptoms and may be able to re-create the problem as directed. These problems usually require only one on-site visit, and can be diagnosed and resolved quickly by an experienced power quality auditor.

Sometimes, steady state problems are caused by building wiring. If the auditor can find the cause of the problem it may be simple to fix it during the site visit. However, there are times when it is necessary to call an electrician to make wiring upgrades before any additional recommendations are implemented. Frequently, these upgrades themselves will eliminate most or all of the problems.

Transient Problems

Transient problems present a very different challenge, and likely will require much more sophisticated equipment to diagnose. Physically larger customers also tend to be electrically more complicated. They are susceptible to all of the problems which plague smaller customers, plus they routinely utilize electrically-driven machinery that can cause additional problems. There are circumstances involving these larger, more complex customers which require follow-up diagnostic checks and/or extended periods of data acquisition and monitoring. The sheer size of some customer facilities may necessitate more than one visit.

Typically, the auditor must perform diagnostic investigations during plant shut-down periods or during other non-operating times. Plant electrical personnel, or the electrical contractor, should be on hand to open panels, check connections, and hookup test equipment leads. The operators for machinery which is to be investigated should be on-hand to operate the equipment during the investigation. It may be necessary to leave a recording instrument connected, but unattended, for a time. In these cases, the auditor should be sure to properly tag the equipment, secure the area, and ensure that all energized facilities are covered to prevent accidental contact. Consult safety procedures for leaving facilities open and unattended.

An important precaution is to be sure that all plant personnel know where the test equipment is installed, and that it must remain in operation. Failing to do this could lead to data loss or equipment damage. There was even one incident where maintenance personnel spray-painted a $15,000 analyzer.