Power fluctuations can have serious consequences for your facility. Blackouts and burnouts can result in lost data when computers crash. Power surges can damage important equipment. In the event of a power interruption to heavy equipment, employees can even suffer serious injury. Uninterruptible Power Supply (UPS) systems protect against such events.
What Are Uninterruptible Power Supply (UPS)?
A UPS system is an electronic system which acts as a buffer between your electrical equipment and disruptions in power from the electrical grid. A UPS is not a standby generator or emergency power system. Instead, the UPS provides enough power to safely shut off equipment in the event of a blackout, or to ride out momentary interruptions in power.
Depending on the type of UPS, the system can provide enough uninterrupted power to switch to a backup generator without a break in power supply.
UPS systems range in size from systems with less than 200 volt-amperes to units capable of protecting entre businesses and data centers. The largest UPS in existence is the 46-megawatt Battery Electric Storage System in Fairbanks, Alaska—a UPS capable of powering the city and its surrounding environs during power outages.
Why You Need to Have an Uninterruptible Power Supply
Power outages alone would make incorporating UPS systems into your business infrastructure a wise move. UPS systems also correct for a variety of other input power problems. Depending on the individual system, a UPS can protect against:
- Harmonic distortion,
- High-frequency transient disturbances,
- Mains instability,
- Oscillation interference,
- Sustained overvoltage,
- Voltage spikes.
Different Types of UPS Systems
Categorizing different types of UPS is difficult, as each manufacturer designs models with different features. It’s not unusual to see characteristics normally associated with one type of UPS appear as a feature on another type, making it vitally important your employees understand the nature of your specific UPS system.
Broadly speaking, eight types of UPS make up the majority of all UPS systems. They include:
- Standby / offline,
- Double conversion on-line,
- Standby online hybrid,
- Delta conversion on-line,
- DC powered UPS,
- Rotary flywheels.
What is a Standby/Offline UPS?
Standby systems are small, inexpensive uninterruptible power supplies often used to protect individual computers. In a standby UPS, backup power is only used if the main power source fails. Standby UPS offer protection against power surges and provide enough energy to safely save documents and shut down computers in the event of power outages.
Line-interactive UPS Systems
A line-interactive system usually uses a multi-variable transformer to increase or decrease outage voltage. The battery switches from charging mode to supplying power if incoming power is lost. Line-interactive systems are popular with small business and departmental servers due to their ability to tolerate continuous brownouts and power surges while maintaining battery power.
What is a Double Conversion On-line UPS?
If your UPS handles power of 10kVA or more, chances are good you’re dealing with a double conversion on-line system. In a double conversion system the batteries are always connected to the system’s inverter. The UPS rectifies AC to DC to charge the battery, then inverts the flow back to the correct AC for powering equipment. This allows the UPS to protect sensitive equipment from fluctuations in incoming utility power.
While double conversion UPS system were once only used for 10kW loads or higher, technological advances have made it possible to use double conversion on-line UPS with loads of 500W or less.
Standby/ Online Hybrids
Standby / online UPS merge the features of standby and double conversion online systems. The system works as an offline UPS within set parameters. When electrical flow drops below or exceeds these parameters, the system switches to double conversion as it adjusts for voltage variation.
Once a UPS standard in the 3-15kVA range, the standby-ferro UPS uses a ferroresonant transformer. Such systems are still common in the oil and gas, chemical, heavy industry, utility, and petrochemical industries due to their hardy nature.
DC Power UPS
DC power UPS systems transform AC to DC, which is then output to DC-compatible equipment. This feature, coupled with the ability to provide backup power in the event of power failures, makes DC power UPS popular in the telecommunication field, where equipment often requires direct current.
One of the most expensive UPS systems available, a rotary UPS stores energy on a high-mass flywheel and can provide protection to entire facilities. Rotary UPS are usually only seen in circumstances where more than 10,000 Watts are used. The flywheel stores enough energy for ten to twenty seconds protection—just enough time for standby generators to take on the load.
Protecting UPS Systems
A large-scale UPS requires frequent maintenance, as the UPS itself represents a potential point of failure in your power grid. Some systems use a string of small-scale UPS systems to provide redundant protection, while UPS systems protecting computer servers often include two or more independent UPS systems, each connected to a different circuit.
Outdoor UPS systems must be able to stand up to the elements, including wind, rain, and temperature extremes. An outdoor UPS may use photovoltaic panels to power its batteries.
Backup emergency systems are essential, but only work of you have employees who understand how to use them. A two-day seminar is all you need to ensure your staff are prepared to get the best out of your UPS system.