WHAT IS UPS? WHY DO YOU NEED A UPS?
An uninterruptible power supply or uninterruptible power source (UPS) is used to provide emergency power to a load when the input power source or mains power fails including spikes, brownouts, fluctuations, and power outages. 

A UPS is typically used to protect hardware such as computers, data centers, telecommunication equipment, or other electrical equipment that could be harmed by overcurrents and voltage sags or spikes. It also protects the data stored on devices against corruption or loss during sudden shutdowns. The three general categories of modern UPS systems are online UPS, line interactive UPS, and offline UPS.
WHAT ARE THE TYPES OF UPS SYSTEMS?
Standby / Off-line UPS: Basically provides surge protection and provides battery backup in the event of a power outage. In an off-line /standby UPS system, the load is powered by direct input power, and the backup power supply circuit will only be activated when mains power fails.

The load is fed directly from the raw mains power instead of the inverter output. The battery charger, battery, and inverter are offline, but the charger and battery remain connected to mains power to ensure the battery is always fully charged. The switch will immediately connect the inverter output to the critical load when the mains power voltage fails or exceeds the limits.

Line-Interactive UPS: Keeps the inverter in line and transfers the battery’s DC current path from the normal charging mode to supply current when power fails. The battery-to-AC power inverter is always connected to the output of the UPS. When the input AC power is normal, the inverter of the UPS charges the battery.  When the input power is off, the transfer switch will open and the power will flow from the battery to the UPS output. Line-interactive UPS provides conditioned power, eliminating voltage fluctuations. 

Online / Double Conversion UPS: The online UPS takes the incoming AC power supply and converts it to direct current (DC) which feeds the battery and the load through the inverter, and then returns it to high-quality AC power, free from voltage fluctuations and other disturbances common in utility power. If the mains supply is interrupted, the batteries feed the load via the inverter without any interruption in the output supply. In this way, our electronic devices are not powered directly from the AC mains, but from the online UPS.  Consequently, our electronic equipment does not need to be shut down even if the main AC power is cut off.
 
WHAT ARE THE DIFFERENCES BETWEEN 'ONLINE' AND 'OFFLINE' UPS?
The main difference between Online UPS and Offline UPS is that online UPS provides power to load from AC mains through a combination of rectifier and inverter whereas Offline UPS provides power to load directly from AC mains. Off-line UPS systems are usually low-cost products designed for usually one or two-user PC installations, they provide less protection against most supply problems and give support for short-term power loss. In an Online system,  If the mains supply is interrupted, the batteries feed the load through the inverter without interruption to the output supply. Due to the nature of the double conversion design (AC-DC/DC-AC), an Online system, provides a much higher degree of isolation of the load from disturbances in the mains supply.
HOW TO SIZE UPS CORRECTLY?

Sizing your UPS solution correctly is an important step in developing an efficient system. You will maintain more efficiency from the UPS  as long as the load matches its capacity. On the other hand, a UPS with insufficient capacity may be unable to support your equipment during an outage or other power problem. Capacity and runtime are the two major factors that should be considered to make the right decision. To ensure efficiency, it is recommended to use a UPS that has a VA capacity rating of at least 15% greater than the total power needed for the supplied equipment. As to the runtime, a UPS with a larger battery could be selected or external battery packs may be added to ensure a continuous power supply. If you undersize UPS systems, the data center will overload the existing power.

Then the UPS will turn off and go into bypass mode. As a consequence, it will not provide protection against power failure or brownouts. However, Oversizing your UPS will result in extra costs for unneeded power.
For deciding the right sized UPS for your application, we suggest you get the grand total VA rating of your devices that need to be protected. The following steps might help you to substantially size a UPS by yourself.

  1. Define how much equipment needs to be protected in your facility. 
  2. List the amps and volts for each piece of equipment, for calculating the VA rating, multiply the voltage by the amperage.
  3. For the grand total Multiply the total by 1.2 for future growth and system expansion. That figure is the maximum size in VA or kVA that your UPS should be. 

The safest way to ensure a correctly sized UPS system, we suggest getting experienced suppliers to commence with a full site survey where they can meticulously determine your requirements. 

For a stable and reliable performance, it is not recommended A UPS to be sized to run at 100% load capacity.
 

WHAT DOES AN AUTOMATIC TRANSFER SWITCH (ATS) DO IN A UPS SYSTEM?
An automatic transfer switch (ATS) is a device that automatically switches the load circuit from one power supply to another (standby) power supply to ensure continuous and reliable operation of important loads They are mainly used for smaller UPS systems below 10 kVA that cannot operate in a parallel configuration. 
HOW TO CHOOSE A UPS AND GENERATOR COMBINATION?
During long drawn-out blackouts, connecting your generator to a UPS system could protect your devices more efficiently. However, your generator and UPS System compatibility is very important.  Therefore it is usually recommended to deal with one supplier for both items in order to eliminate the potential conflicts if the equipment doesn’t work well together. Datrofel Energy & Technology will be pleased to guide you through the choices to select the right online UPS system for use with your generator.
WHAT IS A VOLTAGE SAG?
Voltage sag refers to a short-term reduction in voltage of 10% or much below the nominal mains supply level.  Also known as a dip, a voltage sag shouldn’t be confused with a brownout, which is a longer-term reduction in voltage that lasts for several minutes or even a few hours. On the other hand, a voltage sag event usually lasts less than 1 minute. There are several causes for a power surge. The main reasons are electrical overload, faulty wiring, lightning strikes, and the restoration of power after a power outage or blackout.
WHAT IS A VOLTAGE SURGE?
We can define voltage surge as the sudden increase by 10% or more above the nominal mains supply. Electrical equipment needs to receive supply voltage according to the rated supply of the equipment for reliable operation. Therefore, we can say that voltage surges are power quality problems. Voltage surges cause a rise in line and phase voltage with respect to the ground. The voltage surges can damage electrical equipment.
WHAT IS A BROWNOUT?
A brownout is a dip in the voltage level of the electrical line. When a brownout occurs, the voltage goes down from its normal level to a lower voltage and then returns to the same level. A brownout occurs due to high electricity demand close to or above the generating capacity of a public utility. At this point, the utility can reduce the flow of electricity to some locations to prevent a power outage. These brownouts can last from a few minutes to several hours, at which point electricity demand will likely decrease, allowing the facility to regain full power levels. And power outages sometimes can also occur spontaneously as a result of damage or malfunctions to the grid or a nearby power plant. 
WHAT IS A BLACKOUT
A blackout is when the power totally fails. The term “blackout” usually refers to a large-scale service interruption. Utilities can apply to a series of temporary power outages when demand is far greater than supply. By cutting power partially in different locations respectfully, the power company can limit the demand for power and protect against overloads.  These temporary power outages, called rolling blackouts are a tool grid operators use to manage power balance when supply and demand fall out of balance. By cutting power in short-term and controlled manner, utilities protect sensitive equipment from being overloaded and manage the process of bringing systems back into supply-and-demand balance.
WHAT IS THE DIFFERENCE BETWEEN BROWNOUT VS BLACKOUT?
A brownout is a period of reduced power while a blackout is when you have no power at all. It is regarding the demand and supply in both cases. The term "rolling blackout" is used for a more deliberate process. Rolling blackouts are intentionally produced by the power utilities to provide temporarily relieve the load on an overloaded power grid, similar to deliberate brownouts. Utilities often spread these rolling blackouts to multiple areas for a limited period of time, which helps prevent larger-scale blackouts. 
HOW CAN WE OPTIMISE UPS ENERGY EFFICIENCY?
In UPS systems, because most systems are planned to grow over time, a modular approach may allow for less capacity to be purchased initially and additional modules to be placed in as load increases.
We recommend a consultation with Datrofel’s experienced technical service to take good advice on the options and suggest you the optimum UPS solutions. 

Contact us here  For further information on how Datrofel can support you to increase the UPS efficiency of your data center operations.