How To Make Your UPS System Resilient

Modular UPS systems are now one of the fastest growing areas within the uninterruptible power supplies market. Many UPS manufacturers now offer both types of UPS system but is modular the right choice for your application?

Modular uninterruptible power supplies offer several benefits. The first is vertical scalability. This means that you can add additional modules to a UPS system, in order to expand is capacity. Vertical system capacity expansion is generally limited by the frame size installed. For example, if you have a 120kW frame size, this could take up to three 40kW modules. If you start with a 40kW module installed on day one you could install two modules in the future to give 80kW and three to give 120kW at a later date. Horizontal scalability is also an option and this relies on adding another frame into which additional modules can be installed.

The second benefit of modular UPS systems is that they can more easily provide increased resilience over a traditional mono-block-type UPS design. Within an installed system frame with only one 40kW UPS module there is no redundancy. When two 40kW UPS modules are installed the system can be operate as a 40kW N+1 uninterruptible power supply. The addition of another module allows the capacity to increase to 80kW with N+1 resilience (from three 40kW UPS modules).

Modular UPS system using a single frame only however offer modular redundancy. They do not offer full system redundancy unless two matching system frames are connected in parallel. This format then mimics the same configuration that can be achieved using two mono-block UPS systems installed as a parallel/N+1 configuration.

It is important to consider whether modular redundancy is as good as full system redundancy. Modular redundancy provides a way to increase resilience within the UPS system itself. If a UPS module fails then another module can be used to power the load.

In a typical modular UPS system, the frame houses the electrical connections, system bypass arrangements, DC (battery) connections and remote communications. There is no redundancy for these elements unless a second system frame is connected in parallel.

So whilst modular UPS systems provide redundancy, it is important to note that this is only at the module level. Whilst this does improve overall system resilience compared to a single mono-block-type UPS system, the only way to ensure full system redundancy is to install at least two system frames in an N+1 configuration. Whilst this is technically feasible, it is can be a more costly way to provide system N+1 resilience which can be achieved at around 30% or more less cost using the more common mono-block type UPS system design.

For more information please contact the Eco Power projects team on 0800 612 7388 and they can arrange a site survey to help provide you with the most appropriate UPS system design and configuration. We offer a complete range of datacentre UPS including both modular and mono-block transformer-based and transformerless systems.