What is a Modular UPS?
Modular UPS is not to be confused with Parallel UPS in our definition.
Power Sonic’s definition of a Modular UPS is where a unit is able to provide N+1 or N+X redundancy as well as being able to grow as power requirements increase. This is achieved by adding additional modules which can slot into a chassis on an individual basis.
In environments where total reliability is of great importance, a single UPS can be a single point of failure that can also disrupt many other systems.
To provide greater reliability, multiple smaller UPS modules and batteries can be integrated together to provide redundant power protection equivalent to one very large UPS with additional modules to provide
redundancy if there is failure of one of the modules. In this way, failure of one module will not impact system or site operation.
Modular Three Phase UPS systems are becoming typical on many data centre and critical power applications, this is due to the systems being based on small, light, compact, hot swappable, low cost modules which can be added when needed, or indeed more modules can be added for additional redundancy.
In this blog post we try to cover the merits with also the typical flaws. Most current Three Phase UPS systems have parallel or scaling ability, which enables to add parallel UPS units whenever additional power or redundancy is required.
For example; if 100KVA is maximum load then 2 x 100KVA systems will be required as a bare minimum, this is without taking into consideration efficiency of load or growth. A unique scalable solution is provided
by a Modular UPS approach.
A Modular UPS is generally based on a rack type enclosure that includes battery cabinet at its bottom or in a separate rack, and hot swappable modules located one above the other, which can be added whenever more power is required, or greater level of redundancy is required.
Advantages of a Modular UPS
All UPS systems are designed to work continuously during life time of UPS. A Modular UPS is designed to be flexible when more redundancy is required. Thereby minimising failure. The general idea being, the more modules with free and spare capacity, then there is a greater the level of redundancy. For example, if a load is 80KVA and the modular UPS provided is rated at 120KVA populated by 20KVA modules, then the end result will be N+2. By adding further modules then you can increase the redundancy aspect, thereby reducing the possibility of total UPS failure.
- LOWER COST OF INSTALLATION
Modular UPS can in many instances be more cost effective than installing parallel or scalable UPS systems. For example, if the requirement is for 100KVA with N+1 redundancy, then a modular solution will be 120KVA made up of 6 x 20KVA modules as opposed to 2 x free standing 100KVA UPS systems. The cost of installation will also be lower.
- DELIVERY, OFFLOADING AND POSITIONING
A standalone or parallel UPS is one unit and can be problematic when delivering on site. They can be very large as well as heavy. A Modular UPS can be broken down into parts and assembled back in on site. This can reduce costs on delivery as well as making sites more accessible.
- LOWEST FLOOR SPACE, COMPARED TO OTHER SCALABLE /
Conventional UPS systems take up more space due to the fact they are typically extended horizontally on the floor. The modular UPS typically increases typically vertically in the rack. Thereby using less floor space. Secondly, less UPS batteries need to be used if the conventional UPS has separate battery cabinets.
- GREATER LEVEL OF EFFICIENCY WITH SCALABLE LOAD
A UPS is generally not working at its best when running at 100% load. With a modular UPS by maintaining a high ratio of load to UPS capability will mean that the UPS is working in its most efficient way. For example, if the load is 60-70KVA, then we would recommend that the UPS if in modular format should be 80KVA with one extra 20KVA module, providing a total of 100KVA.
- REDUCTION OF FAILURE DURING MAINTENANCE / SUPER-FAST REPLACEMENT (MTTR)
A typical standalone UPS system will go onto bypass during failure or overload etc. The UPS will generally have to be isolated during repair or technical evaluation to assess the unit. Once assessed and problem found on the failed UPS there is time for part replacement, and if part is not available then further time is required when parts are available and sent to site.
With a modular unit, the faulty module is simply removed and replaced with a new system. This action can take literally seconds as the faulty module will removed and replaced during live conditions so there is no loss of power or loss of UPS backup. Many manufacturers of modular UPS systems however, still have a singular point of failure on the system itself and that is by having a singular static switch. If this fails, then the system fails. Power Sonic provide modular UPS
systems with static switches built into each module.
- GET MORE POWER FROM SAME INFRASTRUCTURE
If, for example, your site is cabled and capable of supporting 2 x 100KVA parallel standalone UPS systems, therefore the load you anticipate putting onto the UPS must not be greater than 100KVA. Otherwise you will not get redundancy, or alternatively you will
overload each UPS. With a modular system if you are aiming to get
redundancy you will only need to add 1 x additional module to achieve this.
For example; if you require redundancy and have chosen a 20KVA scalable modular system, all you will need to do is add 1 x additional 20KVA module. So, based on the example above against 2 x 100KVA systems you will simply have a 120KVA modular system.
Furthermore; if your site is already capable of being able to support 2 x 100KVA parallel UPS systems, then a modular UPS will enable you to have full usage of the infrastructure and enable power growth up to 200KVA rather than 100KVA full load scenario.
- LOWER COST OF BATTERIES
A Modular UPS will as a general rule of thumb, have a centralised battery which is shared by the modules. With a standalone / parallel UPS there is a need to have 2 x separate batteries covering each UPS, thereby increasing battery costs.
Power Sonic can offer modular UPS systems with centralised battery or parallel battery. Furthermore; we can also offer standalone UPS systems with common battery. The choice is yours.
- LOWER COST OF REPAIR
In the event of catastrophic failure of standalone / Parallel UPS and the system has to be replaced in its entirety due to parts not being available or replacement not being available, compared to catastrophic failure of one module then the costs will typically be 10-20 times in comparison to a single module replacement. It will be even worse if both standalone systems if running in parallel are to be replaced.
- LOWER COST OF OWNERSHIP OVER LIFETIME
A singular Modular UPS system will simply cost less to run than if 2 x Parallel UPS systems are running at the same time. For example, if the site has 80KVA load and a 100KVA modular system is purchased then the running costs will less than if the site had purchased 2 x 80KVA standalone parallel systems. A standalone solution may cost more than double to run over the lifetime. Depending on your electricity tariffs the UPS company can provide details of how much energy is
used in every scenario and cost. We can save your site money. We can also recommend other factors on site such as power factor correction and carbon reduction via carbon off set.
A modular UPS system will provide a perfect solution based on many parameters, however cost and functionality nearly always come into play. If you have a requirement for a UPS system please contact one of our experts to help you choose the right solution for you.