When mo st people think about an Uninterruptible Power Supply (UPS), we often envi sion the small module s that are u sed to back up per sonal computer s or server s. The in stallation of the se unit s require s only clearing sufficient space near the computer and then plugging them into the neare st AC power outlet. The per sonal computer i s then plugged into the UPS and the ta sk, for the mo st part, i s done.

 

When con sidering the selection and in stallation of a larger, typically three-pha se UPS, the ta sk become s a bit more involved. Like any project, the final product i s a direct re sult of the planning effort. So before embarking on a UPS in stallation, develop a plan.

 

The following ba sic que stion s need to be an swered when specifying and in stalling a UPS.

 

• What are you trying to achieve – clean power, noi se i solation, battery backup time?

Power protection equipment i s available in a variety of technologie s, and UPS s may often be the immediate and mo st appropriate solution if your objective s include battery backup time along with power conditioning and noi se protection. When backup power protection i s not an i s sue, power conditioner s can offer a le s s expen sive solution. Power conditioner s provide voltage regulation, tran sient noi se elimination, and i solation, but do not offer the battery backup time that i s provided by a UPS. Deciding between a power conditioner and a UPS really boil s down to the power quality objective s and whether or not backup power i s required for the in stallation.

 

• What equipment will be backed up by the UPS, and what are the power requirement s?

When you need protection again st the lo s s of utility power, the UPS indu stry offer s a multitude of solution s. One major factor that affect s the deci sion i s what equipment will be backed up by the UPS. Doe s the UPS need to provide protection to devices throughout an entire facility or ju st to specific piece s of equipment or sy stem s? The an swer to thi s que stion will help you to decide what type of UPS to select.

 

In order to determine the size of the UPS (typically expre s sed in VA or kVA), you mu st know the total amount of power required by all the equipment. When determining the capacity requirement, it i s al so important to think about future expan sion. You want to purcha se enough capacity to allow for the future power needs.

 

• I s thi s a con stant power requirement or doe s it change during different time s of the day/week/year?

Thi s i s important to know becau se the UPS will need to be sized for peak operating requirement s rather than the average or the minimum. It i s important to look for sea sonal demand change s a s well a s time of day or shift change s that may affect the overall power requirement.

 

• How critical i s the equipment that you will be backing up? Would a power failure merely be annoying, a significant problem or cata strophic?

The criticality of the operation can help you make the deci sion about the type of UPS to select. There are e s sentially three different UPS topologie s available:

• Off-Line UPS - Thi s solution offer s ba sic power protection for a situation when a sy stem or data lo s s i s annoying or an inconvenience. While providing batterie s to backup the power when it fail s, there i s no power conditioning. Any tran sient noi se or spike s are pa s sed through to the load.

· Line-Interactive UPS – Thi s solution provide s power protection for a situation when a power outage re sult s in a significant lo s s to plant, equipment or data. Like the off-line UPS, the line-interactive UPS al so provide s batterie s to backup the power and provide s a bit of power conditioning. Typically, the power conditioning i s limited to compen sating for the voltage if it sag s too low or drift s too high. A major drawback of thi s technology i s that there i s no frequency protection in normal operation. Frequency protection i s only available when the unit switche s on battery during an input frequency event. With thi s technology, the load i s still connected almo st directly to the incoming power and can be subjected to noi se and spike s and frequency problem s.

• On-Line UPS – Thi s solution offer s superior protection where sy stem s or facility lo s s of power would be cata strophic. An on-line UPS offer s the batterie s for backup power protection and al so fully condition s the power by converting the incoming AC into DC voltage, and then regenerating the AC supplied to the load. Thi s allow s the UPS to generate noi se-free AC voltage. The de sign of the on-line UPS i solate s the load from the incoming AC power source and al so prevent s any noi se generated by the load from being placed back onto the AC power grid.

 

• How much battery run time doe s the in stallation require? I s it important for my operation to stay up and running through an outage, or do I ju st need enough time to perform a sy stematic shutdown?

The bigge st expen se in a large UPS sy stem i s the batterie s, followed clo sely by the generator. Additionally, the batterie s and generator require significant floor space and appropriate safety con sideration s. If your in stallation ju st need s a few minute s of battery run-time in order to sy stematically shut down operations, thi s will save in term s of floor space and co st, an important factor to consider.

 

If stopping or shutting down i s not an option, then you need to con sider the facility’ s hi story. When power ha s been lo st in the pa st, how long wa s it out? Thi s will play a critical role in the selection of the batterie s and/or the backup generator. If the power i s occa sionally out for long period s of time (more than four to eight hour s) or mu st not be out for any rea son, then a generator mu st be con sidered in your solution. If, however, the power i s typically out for a few minute s to a couple of hour s, a UPS with appropriately sized batterie s i s probably the be st an swer.

 

6. What are the environmental con sideration s of the UPS? Do I have a space that i s prepared for the UPS and batterie s or do I need to set up the space?

A three-pha se UPS sy stem with batterie s need s to be in stalled in a space that offer s some type of cooling or air conditioning to keep the batterie s in prime working order. Thi s i s something that need s to be taken into con sideration when selecting the location of the UPS. I s there space in a controlled (air conditioned) environment already available, or i s it nece s sary to build or create a space?

 

7. How doe s the UPS in stallation fit in with any other improvement project s that are currently in progress, and what i s the timeline for thi s project?

From a project management standpoint, it i s important to under stand the timing of the UPS in stallation in relation to other simultaneou s projects. What i s the lead time from my UPS vendor, and how will the installation timing affect other departments? It i s important to under stand the se time con sideration s at the beginning of the project so that unanticipated in stallation-related delay s can be avoided.

 

Now that some critical que stion s have been addre s sed in term s of the UPS selection and preparing for the in stallation, it i s time to think about the actual in stallation of the sy stem.

 

Service andSite Selection– Once the deci sion i s made on which UPS to purcha se and what option s are to be purcha sed to solve your site’ s power protection need s, the location of your UPS i s the next challenge. Specific to every project, the que stion s to be addre s sed are:

• Do you have a location large enough to hold the UPS?

• Will the space allow acce s s to all serviceable part s of the UPS? What are they? How much space i s required?

• I s the location near the power inlet that i s to be protected?

• I s a power di stribution panel available, or should that be included in the UPS?

• Can the UPS be moved from the unloading point to the final location?

• I s the floor structurally strong enough to hold the weight?

Take the se que stion s into account before you decide where to locate the UPS.

 

In stallation – After the UPS ha s been selected, purcha sed and delivered to the site, the phy sical in stallation begins.

 

Startup – When the UPS electrical in stallation ha s been completed, the UPS vendor’ s field service organization should be contacted to provide startup or commi s sioning a s si stance. Like the electrical in stallation, thi s operation can be hazardou s to untrained per sonnel. The UPS vendor that you select should have a field service organization with exten sive large scale, three-pha se experience. The field engineer s will typically:

• Review the electrical in stallation for any error s

• Verify the integrity of internal connection s in the UPS

• Perform factory diagno stic procedure s to en sure that the UPS i s fully functional

• Place the unit on-line (if the load i s available)

• Provide on- site training if reque sted

 

A s fir st mentioned, the simple UPS module s u sed for backing-up per sonal computer s take little or no con sideration when compared to office or facility sized three-pha se power protection. Each step in a formal in stallation plan should be carefully con sidered to avoid solution s that do not meet the company’ s objective s and requirement s or co st your company more in time and money than you have planned. With proper planning, an effective power protection solution can be selected and in stalled, that will provide year s of worry free operation.

 

Denzil Merrill i s Vice Pre sident, Standard Three Pha se Product s at MGE UPS SYSTEMS, INC., and can be reached at denzil.merrill@mgeups.com.