One of the most critical factors for any successful uninterruptible power supply installation is how it is project managed; transported to site and installed. The technology could be the best in the world but if logistics and installation are left to chance, disaster may strike.

Not many businesses today can ride through unplanned downtime. Chances are, that’s what would happen if project and installation are mismanaged. UPS power protection loads will need to be powered down for as long as it takes to reconnect them to the output supply of the newly commissioned system and this will vary depending upon the complexity of the project, type, size and number of loads. Disruption to business can be minimised with sound planning and good management.

The Importance of Site Surveys. Installing UPS without a site survey is like running blindfold along a busy street. With little idea as to obstructions, direction or potential hazards, it is only a matter of moments before disaster strikes.

A UPS site survey consists of a set of fairly standard questions to establish specific information and areas for further investigation. It is typically a non-charged-for service provided by a qualified and experienced UPS supplier who will investigate logistical, environmental and electrical issues.

Logistics. Logistical issues centre on how the UPS and all associated equipment will be transported and delivered to site, positioned, unpacked and the suitability of its final location. It will consider restrictions or obstacles inside and outside of the building (whether it is a basement or upper floor location where stairs may be involved, for example), whether local authority parking permissions or Police attendance are needed for off-loading and what security and health and safety issues (as in the case of a chemical plant) need to be complied with.

UPS suppliers offer two categories of delivery: kerbside only and delivery, siting and positioning. Kerbside delivery is for smaller UPS (up to 40kg) that can be dropped of by the supplier to a central point within a site to be positioned thereafter by site staff or commissioning engineers.

Delivery, siting and positioning is a specialised service whereby the delivery company employs vehicles with tail-lifts and carries equipment such as trolleys and stair climbers. Larger UPS systems – including battery packs (pre-assembled or in kit form) will be supplied on pallets and require an on-site forklift.

Environment and Location. Environmental issues concern the specific location of the UPS and its associated system parts. This includes factors affecting its performance and operation; physical space, floor loading, ambient temperature, noise attenuation, vibration, dust and humidity, lighting levels and so forth.

Unless physical space is assessed, and the needs of the UPS in terms of air flow considered, the result may be a lack of space that may result in inadequate heat dissipation. Provision also has to be made for easy access for maintenance and inspection and connection and removal of loads and monitoring cables.

Floor loading can be an issue, particularly in computing environments, as many computer rooms employ false floors to allow air ducts for air-conditioning. In terms of UPS and associated battery strings, this may require the use of extendible false legs, placement on raised floor pedestals or a spreader plate to even out weight distribution.

Remote or split locations must be planned for in terms of how the UPS will be monitored. Uninterruptible power supplies generate a range of alarm conditions indicating an immediate or potential failure. Split locations may require additional cabling, monitoring and access. The same would apply if switchgear is to be housed in another area of the site or building.

Electrical Installation. Investigations into electrical installation are primarily concerned with suitability, protection, discrimination and compliance to regulations – both upstream of the UPS and downstream load connections.

The electrical supplies within a UPS system must integrate seamlessly with those already on site and not interfere with other equipment. The site survey will identify the scope of any electrical work, which must be carried out by certified and registered electrical engineers in accordance with local, national and organisation-specific guidelines.

In addition, whether the installation is low or high power rated, it is mandatory that live conductors must be protected from overloads, short-circuits and earth faults.

Testing and Certification. The installation of a hardwired UPS, regardless of whether changes have been made to upstream or downstream circuits, requires the issuing of an Electrical Installations Certificate by a certified electrical contractor. Testing regimes vary, depending upon the UPS size and accessories installed alongside, but include earth fault loop impedance testing.

A UPS cannot provide the same quantity of energy, which is readily available from a normal mains power supply. The value returned from an earth loop impedance test will reflect the impedance of the UPS inverter. The two normal operation states of the UPS (mains present and mains power supply) must be taken into account when using earth fault loop impedance testing to determine fault currents and protective device discrimination.

It is true to say that innovative and sophisticated UPS technology is advantageous but without correct, appropriate and diligent project management, logistics and installation processes, it could be rendered useless. It is worth taking the time and necessary steps at the outset of any uninterruptible power supply project to determine what needs to be done to bring it to a successful completion.

Uninterruptible power supply batteries play a central role in a power continuity plan providing a dc supply of electricity to the UPS inverter when mains power supply fails. UPS batteries utilise a chemical process to produce and store energy. When they age or become damaged they can corrode and leak potentially harmful toxins into their environment. Over time their efficiency also deteriorates. For these reasons UPS batteries must be stored and disposed of in compliance with a number of UK and European directives, most particularly in the UK the Environmental Protection Act 1990. Hazardous Waste Regulations 2005 also apply.

A battery block is a self-contained, electro-chemical device that stores electrical energy for later use. The outer case is usually constructed of polypropylene PVC (which may be flame retardant) and has two protruding terminals (positive and negative). Inside, positive and negative plates are immersed in an electrolyte, typically Sulphuric Acid, to form cells with electrical potential. This is where a voltage is created and then stored when a charging current is applied.

The most common type of battery used in uninterruptible power supplies is Sealed Lead-Acid but there are others: Nickel-Cadmium, for example, or Lithium Ion and Silver Alkaline.

UPS Battery Storage: a battery will age and discharge even when not in use. The typical storage life of a battery is six to 12 months and this very much depends upon the environment in which it is stored, particularly ambient temperature. A battery’s internal discharge rate will also affect its aging process. Without charge over longer periods, battery performance will reduce.

The most important factor for preserving the life of UPS batteries is temperature; the ideal is a constant 20-25 °C (UPS battery life is halved for every five degrees above or below this level). To maintain temperature, a UPS and UPS battery set (particularly those running in crowded data centres) require an effective cooling system, which is a factor to be considered during uninterruptible power supply specification.

For uninterruptible power supply distributors care must be taken to monitor the actual time the UPS and batteries are left without charge as this can lead to deep discharge and potentially result in the need for a full battery set replacement.

UK and European Directives for Controlling Storage and Disposal of UPS Batteries

- Waste Electrical and Electronic Equipment (WEEE) Directive 2002/96/EC

EU End-of-Life (ELV’s) Directive (September 2000)

- EU Batteries Directive (May 2006)

Batteries are classed as hazardous waste due to their toxic components. In essence batteries cannot simply be ‘thrown away’ or entered into landfill. They must be disposed of in a manner that is protective of the environment and to comply with the law in most countries this should be carried out by companies licensed to perform such tasks on behalf of manufacturers (who bear the ultimate responsibility). Riello UPS is one such uninterruptible supply manufacturer that is also licensed to dispose of UPS batteries. Working with a UPS provider with ISO 14001 provides peace of mind especially if they are licensed to carry waste. They will in turn work alongside a licensed disposal company and thus ensure that they growing requirement for uninterruptible power supplies does not harm the environment.

Rising electricity costs and the prospect of energy rationing mean it’s never been more important for uninterruptible power supplies to be correctly sized. Increasingly, power protection customers are being urged to be energy efficient and play their part in tackling climate change. If an uninterruptible power supply is significantly over-sized it will run inefficiently. ‘Undersizing’ will introduce the risk of system overloads.

This is particularly true for a power-hungry end-user such as a datacenter. The latest high-end servers require more power to operate – and greater cooling resources. According to some reports, every megawatt needed to power datacenter hardware draws another 1.5 MW to cool it!

Is UPS Sizing just simple math?

According to business continuity experts, the proportion of business continuity plans invoked by power failures has jumped recently. Why? Either energy supply is less reliable or existing uninterruptible power supply installations are unsatisfactory – or non-existent!

Historically, power protection has been oversized so that, at full capacity, the system itself isn’t overloaded. Oversizing also leads to higher installation and ongoing maintenance costs. Undersizing, however, especially in a busy datacenter where equipment is being continuously added and switched in and out, will soon cause problems.

Whilst an on-line uninterruptible power supply has a built-in automatic bypass for emergencies, running close to design limits with regular overloads is bad practice. Some oversizing is always best.

The secret of power protection sizing

Firstly, the equipment being protected (the ‘load’) must be categorized into critical, essential and non-essential loads.

Critical Loads are the IT and electrical components that make up the business architecture and without which business continuity would be lost: servers, computers, storage devices, telecommunications, security and building management systems. Their power protection will probably require some extended runtime to keep equipment running continuously; probably also redundancy so that if a power outage occurs, and one UPS is unserviceable, another can take over.

Essential Loads are vital to the business (datacenter, machine room or some such) but in their absence some functionality can exist. Some essential loads may need redundancy to be built into power protection, but in many instances back up needn’t be as robust as for critical loads.

Non-essential loads are those that the business can survive without until power is reinstated: printers and canteen facilities for example.

The Power Factor in UPS sizing

An understanding of the importance of ‘real power’ is crucial for power protection sizing. Kilowatts (kW) are a measure of the real power drawn by the load whereas kilovolt-amps (kVA) are a measure of apparent power. The difference between the two is the power factor (pf) and its size can present problems when specifying uninterruptible power supplies.

The greatest efficiency comes from operating at a power factor of 1.0 or ‘unity’. Though computer equipment has been approaching this in recent years, many UPS systems have not kept pace. The solution is to specify an uninterruptible power supply with as high an output power factor as possible – with a power factor of 0.9 set to become the standard. UPS manufacturers like Riello UPS have set the bar at this level with new energy efficient products being released onto the market.

As well as being correctly sized, power protection systems should consist of units offering an input power factor of not less than 99%. This should enable users to cut energy wastage by up to 40%. Harmonics generation and heat output should also be low and today’s UPS should offer a small footprint so as (in the case of a datacenter) not to take up too much valuable revenue earning space.

Scalability

Finally, and looking to the future, power protection should be ‘scalable’. This means additional uninterruptible power supply modules can be added without having to rip out and replace the unit each time power protection requirement increase.

As always, time invested in assessing and categorizing loads, determining their size and power requirements and calculating a correctly sized power protection system will pay dividends. Naturally, UPS sizing consultancy is available from manufacturers such as Riello.

The way to enjoy peace of mind and cost savings from a correctly-sized power protection system, is to think about slightly oversizing UPS, categorizing loads, calculating power factor and being mindful of scalability.

It may sound like the mantra of some fashion icon, but unlike the fickle fashion business, where accessories merely enhance the look of an outfit, uninterruptible power supply accessories play a more functional role in the overall power protection strategy. There to enhance the workability, functionality and reliability of the UPS system, accessories also play a vital role in adding value and overall resilience. UPS accessories include software, adapters, sensors, cable converters, interface panels and bypasses, all purposely designed to work alongside UPS and for implementation in power protection applications.

Software: most reputable uninterruptible power supply manufacturers provide user-friendly management and monitoring software. UPS software displays real-time information in the form of bar charts and values explaining critical data such as mains voltage, UPS load and battery charge percentage.

UPS software enables remote interrogation of logs and operating parameters to help diagnose alarms and potential fault conditions. When instructed, it performs an automated safe power down of protected loads (PCs and file severs, for example) to safeguard them against damaging and costly system crashes.

Adapters: network Management Protocol (SNMP) adapters, USB converters, duplexers and protocol converters expand the communications capabilities of uninterruptible power supplies and provide ease of management across networks and multi-operating platforms.

These devices are usually bespoke-designed for specific customer projects.

Network agents (such as Riello UPS’s NetMan) allows UPS management across a LAN using any of the main network communication protocols – TCP/IP, HTTP and network interface (SNMP). Network agent-enabled uninterruptible power supplies integrate easily into medium and large sized networks and provide reliable communication between the UPS and management systems that are employed therein.

Cable and Protocol/Converters: protocol converters (such as Riello UPS’s MultiCOM) may be used to monitor the UPS using the MODBUS/JBUS protocol on RS485 or RS232 serial lines. It will also manage a second, independent RS232 serial line that can be used to connect other devices such as the network agent or PC running the uninterruptible power supply management and monitoring software.

The device integrates the UPS with control systems and offers complete configurability of the input and output signals. The RS232-USB converter allows uninterruptible power supplies without a USB port to connect to Macintosh, Windows and Linux PCs (provided they have a USB port).

Sensors: uninterruptible power supplies, and UPS batteries in particular, are susceptible to changes in the environment so sensors that keep a check on temperature and humidity are advisable to be used in a power protection system. UPS batteries, in particular, must be stabilised at an ambient temperature of 21-25 degrees centigrade. Even so much as one degree above or below this threshold can seriously diminish the design life of UPS batteries.

Panels: the panels that sit on the front of the uninterruptible power supply unit and act as the operator interface need to be clear, visual, easy to operate and understand plus robust enough to withstand their environment (whether heavy industrial or dynamic IT sites).

In addition, some manufacturers offer a remote monitoring panel designed to provide a detailed overview of the UPS to which it is connected. This panel can provide a range of useful operating information (in a variety of languages – depending upon operator preference) including specific UPS input and output voltage and frequency values and status information on the UPS battery set.

Riello UPS’s MultiPanel, for example, has three independent serial ports – one for UPS monitoring using the MODBUS/JBUS protocol (either an RS485 or RS232 serial line) and others designed for use with UPS accessories such as network agents and UPS monitoring and control software.

When selecting a panel it is advisable to choose one that is compatible with most building management systems, and that has a communications flow LED status indicator and the capability for firmware upgrade via one of its serial ports.

Bypasses: in this day-and-age of continuous uptime and 24/7 operating environments, an uninterruptible power supply maintenance bypass is a must. It allows a UPS unit to be powered down for maintenance without disruption to the load and is typically installed with on-line power systems from 700VA to 800kVA. Many bypasses available from reputable UPS manufactures are ‘plug and play’ with a range of socket configurations, and are usually available in wall mounting and 19″ rackmount formats so as to be able to be sited in server racks alongside computer loads. An additional safety feature is an automatic transfer should the output of the UPS fail due to overload, system fault or accidental disconnection.

So, with uninterruptible power supplies it is wise to accessorise but select carefully. Compatibility is key. Choose accessories that are most closely related to the actual UPS system itself. Sourcing from the same manufacturer is recommended.

Power Supplies and Power Inverters are something you will be involved with if you do a lot of road travel or even one good summer vacation. Power, of course is the key to everything on the road. There are many 12 Volt appliances and accessories available both online and off.

Power Supplies are units that plug into a 110 ac outlet and deliver 12 Volt dc to a set of positive and negative plugs or a cigarette lighter socket, usually located on the front of the unit. Some deliver only a few amps and the bigger units deliver 35 and more. Amps are only important in as far as having enough. Your unit will only draw what it needs, even if the power supply is rated very high and the device only requires low amps.

Don’t even think about that working the other way around. Too small an amp rating attempting to power a higher rated unit will overheat the power supply and damage it. Most quality power supplies have overload protection and fuses to prevent damage and even fire related to such a situation. Best thing to do is be aware of the required draw of devices you intend to power and the capacity of the power supply unit you have in service. Best match is where the power supply has about 10% larger amp rating than the sum of all the devices it is required to power.

Power Inverters are the other side of the coin, they attach to a battery, 12 Volt for our purposes, and deliver power as 110 ac. Worth mentioning that most units include the convenience of a 12 Volt cigarette lighter type socket or two.

The larger the battery the better the result. Often in larger vehicles or dedicated applications you will find multiple batteries connected in parallel or series parallel configuration. This can provide good power for longer periods of time.

Since power inverter applications often rely on battery power that is not being replenished as it is being used, you will discharge the battery. Two pieces of information should be brought to bear before you even get started down the inverter road.

The first; there is a device commonly referred to as a “battery guard”. The function of the battery guard is to keep track of how discharged the battery power is becoming and shut down the power inverter service while there is still enough battery power to start the engine.

The second, and this one is a little confusing, most batteries in common use in motor vehicles are not meant to be discharged and recharged. They are meant to see heavy use, such as starting the engine under most any condition, then be immediately recharged by the vehicle’s charging system. This type of battery is referred to as SLI (starting, lighting, ignition). Fully discharging and recharging this type will damage the battery and you will find yourself shopping for batteries very soon.

The kind of battery that works well with power inverters, and other applications that require continuous power, that brings the battery into a near fully discharged state is called, “deep cycle” or “motive”. The internal differences in construction and materials are beyond the scope of this article. The difference in functionality is undeniable and important. Plan your power inverter applications carefully so you get longevity and service from your power investments.

I would like to add one last solution to this power profile. The more feature rich “emergency jump start units” have built in inverters and convenient 12 Volt power receptacles. With the desirable motive type battery, they provide extended life for laptop computers and recharging cell phones. Emergency jump start units are rechargeable from AC power where is it available and 12v battery power while you are going down the road. They invariably feature an air compressor for low tires and, of course, if you or a fellow traveler need a jump start, you can always use them for their intended purpose.

Happy traveling. It must be time for a cup of coffee and “more power to ya’”.

12 Volt DC Power Supplies | 12 Volt Power Inverters | Emergency Jump Start

In many organization whether its small or large organization, they use Uninterrupted Power Supply (UPS) to protect their systems. Not only the systems it could be anything like machinery, refrigerators, servers, computers or any other electronic gadgets to protect their work from the loss of the data in the event of a power failure. Because they work continuously and they do not shut any of their machines for a single minute, if they do they have to suffer a huge loss so for this reason they use battery. Battery comes into different sizes and the units and as per the use or the need of the batteries. Batteries work same as generator but they are better than the generators. They continuous supply power to your systems in case of power failure. Generator may cause your systems but there is no chance you lose your data in uninterrupted power supply. There are many companies who manufacturers UPS like HP, Dell, Shenzhen Santakups Electronic, cyber Power systems, APC, etc. And it comes into variety of ranges, previously UPS were very expensive. Each UPS has been developed by the company comes into different units, prices and so on. These companies understand the actual need of the UPS. In today’s globalised world, each and every organization works with computers, uses computers. No organization is maintaining books for any records; it is time consuming as well as expensive and it saves lots of time of the company. So, every company whether it is small or large use software for maintaining records. Whether it’s a business centers, data centers, servers or the manufacturing processes they demand power which can be supplied by installing high units of Uninterrupted Power Supply. Now a day’s the Online Uninterrupted Power Supply is considered to be the most expensive and advanced form. No doubt they are noisy, contain cooling fans and require some planning if you want to establish in small office or at home. The main benefit of the Uninterrupted Power Supply is when there is a power cut; UPS switch to its battery and start loading whereas generator takes some time to load. When there is bad power supply, UPS decides that the power is bad and its load remains on the batteries. UPS either switched to the main input or simply dies depending upon the UPS design, units and upon the company.

The design of the Uninterruptible Power Supply is determined to a large extent by the required function and what level of critical cover is expected to protect the load .

At the bottom end of the scale are ‘ Desk Tops’ the Offline UPS system , generally below 1kVA, as its name suggests it provides an unregulated filtered supply to the load at the same time maintaining the state of charge of the battery by a separate charger.

When the utility mains fails or goes out of tolerance the inverter turns on and is connected to the load via a relay. There is a short break while this operation takes place and the duration of this break is called the transfer time.

The Offline UPS system is not suitable where there are large variations in the local utility mains supply, as the load will be directly affected. To overcome this problem a Line Interactive UPS system can be used, the technology operates in a very similar way to the Offline UPS systems whereas the inverter does not provide supply to the load unless a utility mains failure or brownout has occurred.

The Line Interactive UPS system uses an active voltage regulator (AVR) to control the voltage seen by the load during normal operation; this method insures that the load has a constant voltage applied to it. Again these Uninterruptible Power Supplies are more suitable for smaller office environment loads and generally are restricted to a maximum of 10kVA.

Traditionally for larger load requirements the Double Conversion UPS system has been favoured, basically it consists of a rectifier, battery, inverter and static switch. This is generally termed- True On-line UPS -

The term ‘True On-Line’ is used because this type of UPS will really protect your mission critical equipment to the point that if you remove its power source and then re-instigate the power , there will be no effect on your equipment.

How is it work then? The True On-Line Uninterruptible power supply works by having a rectifier, which converts the utility mains ac supply to dc, has the dual function of providing a dc supply for the inverter and also a supply to recharge the battery. Therefore in the event of the utility mains failing or going out of tolerance due to voltage or frequency causing the rectifier to switch off the battery will seamlessly continue to provide the dc supply for the inverter.

The inverter then converts the dc supply back to an ac supply that is voltage and frequency controlled to supply the load. The load is therefore completely protected from any surges, spikes or sags from the utility mains supply.

The double conversion Uninterruptible Power Supply has the added advantage of what is generally called the static switch; this is an electronic changeover power switch, which selects the supply required for the load. The supply can be either the unprotected utility mains supply or the fully protected inverter supply. This feature can be very useful in the event of an overload occurring, which is beyond the rating of the inverter, the load will be automatically transferred without loss to the utility mains supply, transferring back to the protected inverter supply when the fault has been removed.

Ensuring uninterrupted power is a vital part of any organisation’s business continuity planning and can be achieved with the correct deployment of suitable uninterruptible power supplies (UPS). Different types of UPS can be used as stand-alone solutions or in conjunction with one another other. The three main static UPS topologies are as follows: Online (‘On-line’) or Double Conversion VFI (Voltage and Frequency Independent, Line Interactive VI (Voltage Independent)and Offline (‘Off-line’) or Passive Standby.

So what are the main characteristics of an Online Uninterruptible Power Supply? The only UPS for completely break-free supply. An online uninterruptible power supply (UPS) maintains power voltage and frequency variations within prescribed limits and is independent of any fluctuation in supply. It’s not just complete power failure that can affect a modern power-hungry business. The online UPS also conditions mains power to counter the potentially damaging consequences of sags, surges and other everyday power problems.

Because of this combined power protection and power conditioning capability, the online UPS is the preferred choice for critical data and voice processing systems and remote mobile telecommunication sites where there may be a high risk of damage from local lightning strikes and high-energy transients. Furthermore, an online UPS can also act as a frequency converter providing 50/60Hz or 60/50Hz. There are also solutions for 400Hz applications.

Of the three main UPS topologies, the online uninterruptible power supply is the only one that can provide completely break-free protection if the mains supply should fail. And, in the event of the UPS developing a fault or suffering an overload, the online UPS is designed to deliver safe failure to mains. This is achieved through an automatic system bypass.

Typical online UPS applications. Online UPS from manufacturers such as Riello UPS are typically used for specialist operations. They can be easily modified using a range of accessories and ‘small batch’ production techniques. Typical applications for the online uninterruptible power supply include the following: rail equipment requiring extended runtimes, remote telecom sites, industrial applications requiring specialised air filters, water treatment works requiring UPS with raised plinths and high ingress protection, scientific sites at altitude or in tropical areas, military applications requiring ruggedised assemblies, remote sites where only renewable energy sources are available and medical applications requiring isolated supply.

Online UPS are particularly suitable when it’s necessary to expand large-scale Power over Ethernet (PoE) implementations, requiring an upgrade to the current level of UPS protection. Maybe the existing uninterruptible power supply is no longer large enough to power the entire infrastructure or, as in the case of a telecom application with existing line interactive UPS installation, perhaps the available runtime duration is not long enough. When business continuity planning has reached this stage, it may be time to upgrade to an online UPS for maximum power protection.

Sizing an online UPS for current and future needs. Regardless of the application, correct sizing is essential to avoid over- or under-specification that wastes resources or leaves parts of the network vulnerable. Then, once the current load requirement has been correctly established, it is prudent to include an allowance for future expansion. The most common approach is to allow for 25% load expansion within five years. For online UPS (above 10kVA), additional capacity, along with higher operating resilience, can be achieved by adding more modules into an existing system using a parallel architecture.

Whatever the requirements of a business’s power continuity plan, and whatever the eventual uninterruptible power supply solution, the first step should always involve seeking the advice of a reputable UPS manufacturer with a proven track record in power protection. Whether for an online solution or one of the other UPS topologies, a modern consultative UPS specification process ensures that uninterrupted power for mission critical facilities are easy to achieve.

Today’s modern data centres face an uphill struggle. Before even considering power protection, many are facing difficulties even securing enough supply for their sprawling facilities. Research organisation Gartner predicted that by this year (2008) 50% of currently established data centres would have insufficient power and cooling capacity to meet demands. Quocirca found that 43% of data centres are aware of an approaching power constraint with 14% (19% in the USA) having already reached their limit.

 

This is due, in part, to server sprawl as well as a lack of consolidation between procurement, application management and energy use. But even with a complete change around in management data centres still need to elevate power generation and protection further up the boardroom agenda as their businesses, and those of their customers, rely so heavily on power continuity.

 

Data centre power protection must focus on availability, redundancy, resilience and serviceability with uninterruptible power supplies at the centre and as the bridge between mains power and standby power (whether a diesel generator, fuel cell or other source).

 

The most important first step towards uninterrupted power is to categorise loads into critical, essential and non-essential and then size those that warrant UPS protection in terms of their energy use. Critical loads (IT infrastructure, servers, networks, routers and so forth) are those that the business simply cannot function without. They will require UPS protection and redundancy and may even warrant extended runtime. Essential loads (heating and emergency lighting, for example) are those that do not necessarily directly affect business continuity but which may be required for health & safety reasons. They may need UPS protection to ensure their continuity until generator start-up but may not require redundancy. Non-essential loads (printers, canteen facilities) can be temporarily lost in a power failure and do not require any form of UPS protection.

 

Sizing uninterruptible power supplies can be tricky. If it is significantly oversized it will run inefficiently and cost more to install. Conversely, ‘undersizing’ will introduce the risk of system overloads. Whilst an on-line uninterruptible power supply has a built-in automatic bypass for emergencies, running close to design limits with regular overloads is bad practice.

 

UPS Sizing: understanding the importance of ‘real power’ is crucial for power protection sizing. Kilowatts (kW) are a measure of the real power drawn by the load whereas kilovolt-amps (kVA) are a measure of apparent power. The difference between the two is the power factor (pf) and its size presents challenges when specifying UPS.

 

The greatest efficiency comes from operating at a power factor of 1.0 or ‘unity’. An uninterruptible power supply, with as high an output power factor as possible, should be specified. A power factor of 0.9 is the standard set by reputable UPS manufacturers like Riello UPS.

 

Power protection systems should consist of units offering an input power factor of not less than 99%, enabling users to cut energy wastage. Today’s UPS should offer a small footprint so as not to take up too much valuable revenue-earning rack space.

 

An online or double conversion UPS is recommended for the protection of critical telecom or data centre loads. The inverter (which is powered when mains supply is present from a rectified mains supply) continuously powers the load from the UPS battery when mains power fails. The transfer from mains to battery is seamless with no break in supply, which is critical for this type of installation.

 

Various UPS configurations are available including single, parallel and series-redundant with each resulting in a different level of resilience, MTBF (meantime-between-failure) and availability.

 

Resilience is built into the UPS in the form of an automatic static transfer switch. A sensor monitors the output waveform of the inverter. Should the inverter fail due to short-circuit, overload or fault condition, the static switch transfers the load to mains without a break.

 

Planning for the Future: data centre loads are not static and will be under constant change and adaptation throughout the life of the facility. A graduated ‘growth model’ needs to be conceptualized at the outset to allow for future expansion of power protection equipment.

 

UPS Monitoring and Maintenance: the advent of Html capability in the software arena has enabled modern UPS manufacturers to integrate sophisticated onsite and remote monitoring capability within their hardware. In fact, modern systems enable remote 24/7 monitoring (either by the client or at the manufacturer’s facility) of all critical UPS, generator, air-conditioning and fire suppression equipment.

 

Nowadays, modern UPS systems, attached to mission critical equipment, have an internal or external maintenance bypass, which allows servicing to be carried out without having to shut down the whole network and lose vital productivity. Proper maintenance, carried out in a timely and effective manner, can prolong the life of the UPS, increase its effectiveness and achieve a better return on investment.

 

Power protection is vital for today’s data centres and UPS providers like Riello are specifically designing products to suit the needs and constraints of this type of installation. For more information about designing, installing and operating power protection systems read The Power Protection Guide.

 

Major power cuts in Western Europe are relatively rare, but by switching large flows of power around the grid, unintended effects on the electricity network are suffered. For example, call short circuits and the inrush power often occur, for example by switching off large loads or this may be caused by distant lightning, this is why people make use of power protection systems .

 

Sensitive equipment can be impaired or seriously damaged. The energy supplier regulates the voltage and frequency of the network at it’s the entry into the electricity supply but is to constantly disturbed for many reasons. Uninterruptible power supplies allow local fluctuations and losses to be offset by devices with electrical energy from batteries to support the constant power flow to avoid potentially catastrophic damage to all kinds of electrical equipment, in particular TVs and computers

 

Power protection systems consist of batteries, electricity judges and an electronic control and regulation device. Basically when your power drops this device steps in to either add more power or replace the power if you were to have a total power failure.

 

Uninterruptible power supplies are manufactured from a capacity of about 300 VA up to several 100 kVA. The performance is mainly influenced by the capacity of the current judges. Another major feature of a UPS is the maximum bridging time, and the capacity of accumulators.

 

It may, depending on the requirement and capabilities of the unit add extra power for a few seconds up several hours. Uninterruptible power supplies bridging time through additional batteries can be extended up to a capacity of about 1500 VA. Computers in smaller data centres will have a power failure shut down automatically in place before the bridging time has expired. Open files and, for example, sensitive databases, will be closed by controls to prevent data loss.

 

The basic functions of a UPS usually include a regular automatic load test in which the accumulator in the ongoing operation with the connected power supply; it constantly tests the incoming power levels to make sure they are safe for your equipment. After 3 to 4 years, the batteries should be replaced to ensure an ongoing high quality of protection.

 

Uninterruptible power supplies are not un-needed luxuries they protect electronic equipment in the home against the highs and lows of the power supply. A sudden spike in the electricity supply can easily cause major damage for example to a hard drive. Power protection systems keep the power supply at a constant level and stop these sudden and often unnoticeable fluctuations that can cause thousands of pounds worth of equipment damage in an instant.