Most professional energy managers and engineering staffs at industrial and even some commercial organizations understand the differences between power-quality and power-delivery reliability. The quality and reliability of power supply is of vital importance to their businesses. The impact of sags, surges and outages on the system can translate into a heavy economic impact in the form of lost production time and product waste.

To meet the needs of these sophisticated customers, special interest utility groups in various technical organizations around the world are addressing power-quality issues. IEEE meetings typically include several sessions on power quality, and the CIRED meeting in Nice, France this month has dedicated sessions on the topic. In addition, the Electric Power Research Institute (EPRI) has funded a broad array of power-quality research studies in the 1990s.

The reason for all of the interest and concern is the continuing increase in overall electronic load sensitivity. The industrial operations of modern plants are built around sophisticated electronic controls that are directly affected by voltage surges, sags, transients, momentary interruptions in service and harmonic distortions. This load sensitivity crosses over from computers and control instrumentation to what we could call "offensive" equipment used in industrial applications, namely variable frequency (or adjustable speed) drives. Programmable logic controllers and distributed plant control systems are especially load sensitive. While many voltage sags and surges encountered by users may be out of their control, many harmonics-induced problems caused by the pervasive use of load-sensitive and offending equipment is not.

The concern over power quality arises from the customer's need for continuous operation of today's more tightly integrated manufacturing processes. Precision goods and products, such as semiconductors and pharmaceuticals, and tightly integrated processes, such as papermaking, can suffer significant disruptions in the manufacturing process due to momentary or longer outages and voltage fluctuations. In addition to the resulting manufacturing process interruptions, physical damage to electrical and process equipment can also occur. On average, an outage can result in damages that run into the tens of thousands of dollars per incident.

The growth of power reliability and power quality-related spending has now reached more than $1 billion per year, according to one EPRI study (when equipment such as uninterruptible power systems are included). As North American and many European industrial plants continue the move to operate facilities at higher capacity utilization levels, the potential for disaster looms larger.

While today most customers typically work with their local utility to resolve power-quality issues, it is unclear if this arrangement will continue to work in a re-regulated electricity market. Tracking down sources of power-related problems might become more difficult, especially in light of the tight pocketbook strings that many commercial and industrial users have when it comes to re-solving these types of problems. In the future, determining where the real problems lie could lead to the development of a third-party arbitration business.

Industrial firms view voltage instability as their biggest concern while commercial and retail companies rank outage duration as the most critical factor. Certainly, many of the larger organizations in both industrial and commercial sectors already have uninterruptible power supply equipment, but most mid-size and smaller companies do not. If the problem was bad enough, more companies would be forced to take some action, but many simply put up with the limited number of interruptions per year and absorb the cost, regarding investments in remediation or backup systems as not quite a cost-justified proposition at this time.

Industrial electricity users want to achieve high-capacity utilization levels at their plants while minimizing operating costs and avoiding process interruptions. Commercial and retail sites want to maximize availability of services throughout the business day.

In today's environment, power quality can be effectively monitored, faults can be recorded, problem sources can be pinpointed on both sides of the meter, and resulting corrective actions can be taken. What we are likely to need in the future will be any array of equipment and services to mitigate and resolve power-quality problems in real-time, in advance of the actual occurrence of a voltage sag, surge or momentary interruption.

Working not only with technology, but also with qualified specialist organizations, power-quality and reliability problems can and will be successfully addressed. Although power-delivery reliability is not a key issue in half of the world's economic regions, power-quality issues often are.

Chuck Newton can be reached at Newton-Evans Research Co., Ellicott City, Maryland, U.S., (410) 465-7316 or via e-mail at The company's Web site address is