Modular UPS systems are gaining momentum lately due to an attractive concept of responding to power protection needs as you grow. The concept allows UPS capacity or redundancy to be increased when needed, through small, lightweight, compact, hot-swappable, low-cost modules, without allocating additional floor space. The merits however come with certain flaws, the article considers both.
The modular UPS approach has the following advantages over standard UPS solutions:
1.Lower floor space.
Most of today’s 3-phase UPS systems are scalable, allowing additional units to be added in parallel units for additional power or redundancy. Modular systems are based on a rack-type cabinet that includes a battery cabinet at its bottom and small, lightweight interchangeable modules located one above the other, which can be added as needed. This scale-up approach occupies about 25% of the floor space, compared to standard UPS units with the same total power capacity.
two. Greater availability of energy.
UPS system availability is defined as the percentage of time that conditioned power is available. If a UPS never failed, its availability would be 100%. Unfortunately, UPS systems or their backup batteries fail, and during repair time no conditioned power is available to protect the load. The modular approach reduces repair time to just a few hours for a technician to arrive and replace the faulty module, compared to the 24 hours or more it typically takes for a service engineer to arrive and repair the system.
3. Greater efficiencies.
The efficiency of the UPS reaches its maximum level when the load is at its maximum rating. The ability to increase UPS power by adding small modules when needed, while maintaining a high ratio of total load to total UPS capacity, makes it the most efficient solution.
Four. Minimal probability of UPS failure during maintenance.
Reviews indicate that 30% of UPS failures are caused by human error during UPS repair or maintenance. The modular approach allows for on-site replacement and isolation of the failed module, which is sent to the service center for repair, reducing the probability of UPS failure during service.
The modular UPS approach has the following disadvantages over standard UPS solutions:
1. Limited power output.
A modular approach requires a relatively high number of small, lightweight parallel power modules. Most UPS systems are based on modules, which can be operated by a single person, located in a 19-inch rack. For additional power, manufacturers recommend adding additional racks in parallel. The probability of failure when more modules are connected reduces the Availability advantage. Furthermore, the inconvenience and high maintenance costs will also increase as the number of modules increases, making the modular approach impractical for systems exceeding 4 or 5 modules in parallel.
two. High probability of single point of failure (SOP).
Unlike conventional stand-alone UPS systems, each equipped with all the necessary UPS function blocks. A single failure in certain functional components, if common to all modules in the rack, such as the common battery bank, transfer switch, control and display units, can cause a total output failure.
3. Higher Initial Investment.
Generally, the initial installation of a modular UPS includes the Rack and all common components. However, this investment may pay off in the future due to increased efficiency and reduced operating costs, as well as the reduced financial costs associated with the Grow as you Go approach offered by the Modular UPS architecture.
Conclution In conclusion, the modular UPS approach is not always the best solution for all scalable UPS needs, but should be considered as part of an overall UPS strategy. Also, to see the whole picture, selecting a modular approach requires in-depth knowledge of the particular UPS design, including detailed information on common elements, which is not always provided by UPS manufacturers.
