Comparison of Centralized and Distributed UPS Systems

Comparison of Centralized and Distributed UPS Systems:

In the backup power systems of UPS, there are two traditional deployment methods: centralized and distributed. From a technical perspective, their goals are the same: to ensure continuous power supply in adverse power supply conditions such as voltage surges, voltage drops, complete power outages, frequency variations, and other power-related issues. Although their goals are similar, the two approaches differ in how they address the problem. Each solution has its advantages and disadvantages, which need to be determined based on the organization's long-term or short-term needs.

Distributed UPS:

Distributed UPS is directly installed on or near the server racks, connecting all servers to the UPS hardware, leaving little or no space between the hardware and servers. If we compare distributed UPS to flashlights installed every 4.5 meters in a specific area for illumination, centralized UPS can be compared to a large spotlight that can illuminate a radius of 30 meters. If one flashlight goes out in the distributed UPS, it will only darken the surrounding 4.5-meter range, but if the large spotlight suddenly goes out, everything will become pitch black.

1. Reliability: Higher proximity strength

For an organization's IT network and power supply system, the greater the distance between servers and associated UPS, the higher the risks the power faces, such as noise interference, grounding and/or loose wiring issues. By directly installing distributed UPS on or near the server racks, the distance between them is shortened, greatly reducing the possibility of wiring faults along the power line path. Deploying self-contained backup power throughout the network prevents widespread power outages that centralized UPS deployments may cause.

2. Easy Installation and Integration

The portability and high maneuverability of distributed UPS make installation and migration very easy, making it an ideal choice for data centers that require high maneuverability. The high proximity of server racks also gives distributed UPS an advantage in Ethernet network connectivity.

3. Better Cost Control for Small Organizations

Since distributed UPS is not designed for the entire enterprise network but only for individual server racks within the network, adopting this solution typically means reducing initial costs and scaling requirements. For small organizations or temporary deployments, distributed UPS provides a cost-effective method of control while reducing complexity in infrastructure and equipment maintenance.

4. Improved Space Utilization and Stable Output

Centralized UPS systems typically use online double-conversion architecture, providing a higher level of power stability and eliminating most power interruptions such as voltage spikes, distortion, and voltage fluctuations. On the other hand, the design of distributed UPS accommodates power variations through an interactive line architecture, which means abnormalities propagate to end devices. Additionally, in a centralized backup architecture, UPS is separated from server racks, providing valuable space for server hardware utilization.

5. Improved Economies of Scale

To increase the capacity of a distributed backup architecture, data support personnel must manually add additional UPS units to each server rack, which can be a tedious and inefficient task in large enterprises. Besides reducing valuable rack space available for server hardware, this architecture also multiplies the devices that data technicians need to monitor and maintain. In contrast, establishing redundant capacity in a centralized UPS is a straightforward step, saving significant time and effort.

Disadvantages: Low Energy Efficiency and Cost Issues

The use of centralized UPS requires larger floor space, and the planning, installation, configuration, testing, and debugging processes are relatively complex. Many companies tend to overestimate demand when choosing centralized UPS. The energy wasted due to overestimating capacity requirements in centralized UPS can reach up to 25%. This excess "energy" results in excess "heat," increasing the cooling system requirements of data centers, thus leading to higher energy costs. Such UPS systems typically require

 dedicated air conditioning systems to handle the additional heat output. Apart from the cost associated with increased cooling requirements in data centers, the price of centralized UPS is significantly higher than its lightweight counterpart, i.e., distributed UPS.

Keywords: Centralized UPS, Distributed UPS, reliability, proximity strength, easy installation, integration, cost control, management efficiency, stable output, space utilization, economies of scale, energy efficiency, cost.