UPS – Data Centre, Disaster Recovery Centre & Communication Centre.
Today’s Data Centre, Disaster Recovery Centre & Communication Centre house mission critical equipment. Any downtime in the centres can cost you millions of Rands. TechNocRacy offers cost effective Power Engineering Design and Solutions to minimise downtime. By minimising downtime it benefits you by reducing expenses and increasing uptime and PROFITS.
An uninterruptible power supply (UPS) is an electronic device that continues to supply electricity to the load for a certain period of time during a utility failure or when the line voltage varies outside the normal limits.
Its typical application is provide backup power to any electrical equipment. Large models are used to power up the Data Centre, Disaster Recovery Centre & Communication Centre equipment.
The generic standard for UPS systems is IEC 62040-3, which defines limits on the amplitude and duration of deviation of the output voltage acceptable for switch mode power supply (SMPS) loads.
To make a power supply uninterruptible, you need an energy storage backup battery, an AC-DC charger and a DC-AC inverter.
There are four main types of power backup supplies: Standby, Line Interactive, Online and Rotary Online.
All of them use battery backup when the grid fails, but under normal conditions they handle the power differently.
Note, unlike generator sets, none of them needs any mechanical moving parts.
A Standby UPS includes a transfer switch that switches the load to the battery with an inverter should the primary AC source fail.
The typical transfer time is between 2 ms and 10 ms depending on the amount of time it takes to detect the lost utility voltage and turn on the DC-AC inverter.
During this time the power to the load is momentarily interrupted. The equipment’s power unit should have a larger hold up (“ride through”) time than UPS transfer time to avoid data loss.
For reference, SMPS PSU for computer equipment is required to have at least 16 ms hold-up time at the rated load.
Since in such device the inverter operates in standby mode and starts up only when input source fails, the SPS has the highest efficiency (95-97%) and reliability.
Because it is also the cheapest UPS power supply, it is the most common backup type used for PCs. Note, in some older systems the inverter generated square-wave type output rather then sinusoidal, which cause problems to some sensitive equipment.
The Ferroresonant Standby UPS has an additional ferroresonant transformer that shapes output voltage and stores some energy for a smoother transfer. Its main drawback is instability when it is loaded by an SMPS with a PFC front end. For this reason such systems are no longer commonly used.
Line Interactive UPS under normal conditions smooths and to some degree regulates the input AC voltage by a filter and a tap-changing transformer. The bi-directional inverter/charger is always connected to the output and uses a portion of AC power to keep the battery charged. When the input source fails, the transfer switch disconnects AC input and the battery/inverter provides output power. The typical efficiency is 90-96%.
Online UPS always delivers all or at least a portion of the output power through its inverter even under normal line conditions, and therefore provides true uninterruptible power. There are two main types of on-line UPS: Double conversion and Delta conversion.
Double Conversion Online UPS is continuously processing the whole power through a series connected AC-DC rectifier/charger and DC-AC inverter. Although such a type provides power factor correction [PFC] and better output voltage quality than the previous types, the Double conversion results in reduced efficiency (80-90 % typical). This type is common for critical load applications.
Delta Conversion Online UPS includes an additional “Delta Converter” that delivers a portion of the energy directly to the load and provides power factor correction [PFC]. Such partial bypassing the rectifier / inverter stages during normal operation results in higher efficiency (up to 97%).
Rotary Online UPS with Generator uses the inertia of a high-mass spinning flywheel to provide short-term ride-through in the event of power loss. The flywheel also acts as a buffer against power spikes and sags, since such short-term power events are not able to appreciably affect the rotational speed of the high-mass flywheel.
It can be considered to be on line since it spins continuously under normal conditions. However, unlike a battery-based UPS, flywheel based UPS systems typically provide 10 to 20 seconds of protection before the flywheel has slowed and power output stops.
It is traditionally used in conjunction with standby diesel generators, providing backup power only for the brief period of time the engine needs to start running and stabilize its output.
The Rotary Online UPS with Generator is generally reserved for applications needing more than 1000 kilowatts of protection, to justify the expense and benefit from the advantages rotary UPS systems bring.
A larger flywheel or multiple flywheels operating in parallel will increase the reserve running time or capacity.
They are normally designed to provide very high current output compared to a purely electronic UPS, and are better able to provide inrush current for inductive loads such as motor startup or compressor loads, as well as medical MRI equipment. It is also able to tolerate short-circuit conditions up to 17 times larger than an electronic UPS.
In Data Centre, Disaster Recovery Centre & Communication Centre environment where reliability is of great importance, a single huge UPS can also be a single point of failure that can disrupt many other systems. To provide greater reliability, multiple smaller UPS modules and batteries can be integrated together to provide redundant power protection equivalent to one very large UPS. “N+1″ means that if the load can be supplied by N modules, the installation will contain N+1 modules. In this way, failure of one module will not impact system operation.
Many computer equipment offer the option of redundant power supplies, so that in the event of one power supply failing, one or more other power supplies are able to power the load. This is a critical point – each power supply must be able to power the entire server by itself.
Redundancy is further enhanced by plugging each power supply into a different circuit (i.e. to a different circuit breaker).
Redundant protection can be extended further yet by connecting each power supply to its own UPS. This provides double protection from both a power supply failure and a UPS failure, so that continued operation is assured. This configuration is also referred to as 2N redundancy.
The UPS that we supply can easily interface to generator set, thus ensuring power continuity.
Power Management requires the UPS to report its status to the end user, via a Serial, Ethernet or USB port.
The Power Management software can be installed on any operating system, is easy to configure and has a user friendly dashboard.
Reports and alarms can be emailed and sms.
The Power Management software must able to gracefully shutdown servers that it is supporting if power is not restored to the UPS before standby time expires.
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