Electrical Power Quality changes hourly, these changes affect nearly every system’s reliability in your facility and the bottom line of your business.
While most are concerned about “the other” electrical service issue, Power Reliability (e.g. power outage), the occurrence of such an event is infrequent as compared to Power Quality changes. An outage does have an extended negative effect on your bottom line however, one that is beyond the loss of productivity during the period of the outage. This extended negative effect has to do with the damage to computer, network, building automation, process control and many other systems. This type of damage can be immediate but often is not; it appears in the hours and days after a power outage event but can be prevented with the proper Power Quality device.
The effects of Power Reliability and Power Quality changes can be easily addressed however it takes a bit of knowledge. Most people are familiar with the Power Reliability equipment so we won’t get into great detail but they are: uninterruptible power supplies (e.g. battery backup) and on-site emergency power generators typically fitted with automatic switchover gear (from utility to on-site generator). These systems vary in size and complexity depending on need from basic “under desk” battery backup and portable generators to room size UPS systems and full time, on-site power generation. This equipment however does not address Power Quality; it only addresses reliability, the point at which there is no electrical service.
Since the Northeast power outage is fresh in our minds lets look at the sequence of the event as it pertains to a facility and its equipment. First, people interviewed in the news described a surge immediately before the outage; others described the power going “off”, then “on”, then “off” again. These symptoms are common in electrical power accidents or sub station / transmission equipment failures and cause damaging surge activity. If a facility has an uninterruptible power supply and/or on-site emergency power generation this capitol purchase equipment needs to be protected from these outage symptoms and even more catastrophic electrical surges such as a lightning strike to the electrical utility. Power surges of this type often disable entire emergency backup power systems at the time when they are needed most! In addition, the load down stream of the emergency power system (the building & its equipment) needs to be protected from the automatic switch over from utility to on-site generation because this action causes significant transient voltage surges too. Finally when the load (a building full of equipment) is energized as the utility restarts, it often causes damaging spikes & surges from in-rush currents to equipment, regardless of the presence of on-site emergency backup power system. These effects either cause immediate failure of equipment or more often weaken or partially damage equipment causing failure in the near term.
As previously mentioned, Power Quality changes hourly and this is caused by external power activities as well as ones within a building. Shift changes at large operations which share the same utility company sub station as your building, power company equipment failures, neighboring companies’ operations within the same business park, lightning strike, utility accident and simple utility company sub station switching are all external events that affect the quality of power coming into your building’s service entrance. Also, within a facility there is a variety of equipment which causes Power Quality issues and they range from large copiers and HVAC system variable speed drives to elevator M/G sets and chiller pump motors; generally most inductive loads.
While management often budgets for systems related to Power Reliability they are unaware that it’s Power Quality which affects their bottom line every day. These effects are typically unexplained building automation failures, network “lock ups”, regular electronics module replacements, heating of electric motors, pre-mature lighting failures and more. The information on one of the most important devices a facility could install for Power Quality, a UL listed Surge Arrester, seems nearly non-existent or in many cases confusing even to the technical staff. Since a UL listed Surge Arrester is one of the most important, and one of the least costly equipment purchases a facility could make in protecting their bottom line, let’s explain some of the details and eliminate the confusion.
A centralized approach to addressing protection and greatly improving electrical Power Quality is what engineers, on-site power generation equipment suppliers, building automation integrators and others are becoming familiar with and are beginning to strongly recommend. All too often Power Quality is addressed with commonly known devices called surge suppressors, officially termed “Transient Voltage Surge Suppressor” or “TVSS”. Knowledgeable people know it’s a centralized “Surge Arrester” they need (also an official term) but there’s more to it than just a name as you will see. The confusion and even a bit of skepticism enters the picture from claims in the marketing of these devices, mixed with a few facts and little or no information on, independent, third party certifications (Underwriters Laboratory) of surge protection equipment.
1. First, the National Electrical Code states “a TVSS shall be a listed device” (NEC Article 285.5) meaning a surge protection device must be Underwriters Laboratory (UL) Listed to be installed under the electrical code; this is mainly for safety reasons. This listing requirement eliminates a large number of products offered on the market as electrical power surge equipment. Yes, believe it or not there are quite a number of devices with no UL listing / certification of any kind, so do yourself a favor and confirm that a device being considered has the official UL mark to avoid embarrassment from electrical code inspection and costly replacement.
2. Next, for the balance of devices considered, check the type of UL Listing category or better yet, obtain the UL Listing file number and view the product’s Listing File on UL’s web site. There are two general categories, for electrical power service surge applications, for which a particular device is UL Listed; the difference between the two is significant! The categories are: UL1449 “Transient Voltage Surge Suppressor” (a.k.a. TVSS or surge suppressor) or ANSI / IEEE C62.11 UL “Surge Arrester”.
Under the common “Transient Voltage Surge Suppressor” listing there are a couple hundred manufacturers selling thousands of products; products range from simple plug in power strips to the most expensive, sophisticated looking, permanently wired, modular suppressor systems you’ve ever seen. Devices with a “Transient Voltage Surge Suppressor” UL1449 listing (including those with IEEE C62.41 test score) have never been evaluated by UL as to the effect of the suppressor on connected loads or the adequacy of the suppression level to protect connected equipment from damage due to transient voltage surges. Of course UL has tested them to be certain of their safety (e.g. fire hazard, shock, etc.) but not to see if they protect your equipment or improve power quality.
On the other hand a “Surge Arrester” marked with UL and with ANSI / IEEE C62.11 is equipment which has been tested to afford protection against surge-related damage to secondary distribution wiring systems and/or to equipment connected thereto. The models with this listing have been tested to see that they meet or exceed their published performance specifications which include passing the ANSI / IEEE C62.11 spec and, in the most catastrophic failure mode, render themselves safe.
3. Third, since the goal is to install a device that actually has been third party (UL) certified to protect wiring and connected equipment, the “surge suppressors” in step two are eliminated. In reality there are a small number of specialized manufacturers who produce ANSI / IEEE C62.11 UL Listed Surge Arresters.
4. Finally, compare the performance specs of the few Arrester listed models. Look at the Maximum Continuous Operating Voltage or “MCOV”, the electro-magnetic (EMI) and radio frequency (RFI) filtering and the initial clamping voltage. The higher the MCOV figure and the lower the initial clamping voltage the better, this is a good indication of quality in design and construction; the interference filtering performance will be important with relationship to automation, control and communications systems.
These steps will provide decision makers with fact based qualifiers in considering this specialized electrical power protection / power quality equipment. Actually UL Listed Surge Arresters are the equipment management believes they are receiving when a “surge suppressor” (i.e. TVSS) device is installed but they later become skeptical when the investment fails to improve Power Quality or protect equipment and the facility.
Generally speaking, the quality of electrical power has either remained the same or in most cases has become worse even without the effects of a “power outage” event. And keep in mind too, that with the expediential growth in digital technology there is an increase in the demand for high quality, low voltage which cannot be met without first obtaining high quality, high voltage. These reasons alone are enough to review existing facility infrastructure and implement this type of relatively inexpensive, easy to identify, critical, Power Quality device as part of a reliability or risk management action.
Ramon Esparolini is Vice President of RayMark Engineering an exclusive marketer and consultant for power quality equipment in commercial, industrial and residential applications. Formerly Ramon Esparolini was Managing Director of USA operations for Klotz Digital AG, the worldwide leader in fiber optically based digital audio control, distribution, processing, and routing for the broadcast industry. For more information contact Ramon Esparolini at RayMark Engineering in Atlanta at 770-281-8821.