A beginner’s guide to uninterruptible power supplies
An Uninterruptible Power Supply, or UPS, provides backup power when the mains supply is interrupted and can also help protect connected equipment from problems with power quality.
In a recent Legrand webinar, UPS specialist Matthew De Frece introduced the basics of UPS systems, including how they work, the different configurations available and what to consider when choosing and maintaining one.
What is a UPS?
A UPS provides temporary backup power to connected equipment if the main electrical supply fails.
Unlike a standby generator, which may take time to start, a UPS responds immediately. This can keep equipment running during a short outage or provide enough time for systems to shut down safely.
UPS systems can also help protect equipment from issues such as fluctuations in voltage, making them particularly useful in environments where continuity is important.
What types of UPS are available?
The webinar covers several common UPS configurations and how they differ.
A line-interactive UPS provides protection from power interruptions while also helping to regulate variations in incoming voltage. These systems are commonly used for smaller applications where straightforward power protection is required.
An online double conversion UPS provides a higher level of protection. Power is continually converted from AC to DC and back to AC before reaching the connected equipment, helping to isolate the load from issues with the incoming supply.
For larger or more demanding applications, modular UPS systems provide greater flexibility. Capacity can be increased by adding modules as requirements grow, while redundancy can also be built into the system.
UPS sizing and battery runtime
Choosing a UPS involves more than looking at its power rating.
The webinar explains how factors such as the connected load, power factor and redundancy requirements all affect UPS sizing.
Battery autonomy is another key consideration. This refers to how long the UPS can continue powering connected equipment when mains power is unavailable.
The required runtime will depend on the application. Some systems may only need enough battery capacity to support equipment until a generator starts or a controlled shutdown can take place. Others may require a longer period of backup power.
Choosing the right UPS battery
The webinar also looks at two common battery technologies used with UPS systems: Valve Regulated Lead Acid, or VRLA, and lithium-ion.
VRLA batteries are widely used in UPS installations, while lithium-ion batteries can offer benefits including a longer service life and reduced size and weight.
The most suitable option will depend on the requirements of the installation. Battery condition is also important to the reliability of the UPS system, so regular testing and maintenance should form part of its ongoing management.
UPS efficiency, generators and installation
UPS efficiency can affect operating costs, particularly in larger systems that run continuously.
The webinar looks at how efficiency can vary depending on the UPS configuration and operating load. It also covers considerations when integrating a UPS with a standby generator.
Other technical areas include static bypass arrangements, neutral earthing and the standards and regulations that apply to UPS installations.
Correct system design and specification are important, particularly where the UPS is supporting critical equipment or more complex infrastructure.
Watch the Legrand UPS webinar
Legrand’s “UPS Systems: The Basics” webinar introduces the key areas involved in UPS technology and system design.
The session covers:
- UPS configurations and operating principles
- UPS and battery sizing
- battery autonomy
- VRLA and lithium-ion batteries
- power factor
- UPS efficiency
- generators and UPS systems
- testing and maintenance
- relevant standards and regulations
For anyone involved in specifying, installing or supporting power protection systems, the webinar is a useful introduction to the fundamentals of UPS technology.
Register for the next Legrand webinar
Want to learn more about UPS systems and power protection?
Register for the next Legrand webinar to hear directly from Legrand specialists and learn more about UPS technology, applications and system design.
