All offices need backup devices. A power cut can mean hours of downtime, productivity loss and critical data loss from servers and desktops, if there is no appropriate backup system. All critical equipment in an office, which need to be in continuous operation and demand high level of data integrity and availability, require uninterrupted power supply. Since utility power is not dependable, UPS is the only solution. An UPS can backup critical loads like servers and PCs in a transfer time of less than 20 minutes and thus, prevent this loss. Besides this application, there are UPS’ which are used for providing power redundancy in critical network infrastructures.
By Srabani Sen
Thursday, December 16, 2010:Types of UPS required
According to Venkat Rao, country manager, medium and large UPS systems, Emerson Network Power (India) Pvt Ltd, there are three standard technologies available in static UPS—offline, line interactive and online. Offline UPS systems—are the least expensive of the three—switches from utility to battery power only when the utility fails. Its usage has been reduced in offices but it is suitable for users looking for simple protection such as domestic use, in the range of sub 3 kVA.
Line interactive systems are similar to offline systems, the only differentiator is that they provide constant monitoring of the integrity of utility power and correct voltage when input voltage fluctuates within certain band. This technology is available in sub 20 kVA range and gives slightly better protection than offline system. It is more suitable for the SOHO segment.
“Line interactive UPS uses a separate charger circuit to charge the battery and goes into inverter mode only when the mains are off. The main advantage of this design is that the inverter/converter unit is always connected to the output, powering the equipment. The design allows for a faster response to a power failure than a standby UPS. The inverter/converter is also normally fitted with circuitry to filter out noise and spikes, and to regulate the power output,” explains Gaurav Burman, director, transaction business, American Power Conversion (APC).
Online UPS, also known as double conversion system, are expensive owing to their complex design and functionalities. These units are available in 3 kVA range. “In this system, all power components are continuously online, hence the name. As incoming power is converted twice, during rectification stage input disturbances get eliminated, and load experiences clean and regulate voltage generated by the inverter. These are used for all mission critical business applications in all verticals,” says Venkat Rao
Online UPS use double conversion technology to convert AC power to DC power and back to AC. Here, the primary power sources are batteries of the UPS and the utility power is considered as secondary power source. “Simply put, the load connected to the online UPS always runs on batteries regardless of whether there’s a power failure or not. Due to this, there is zero switchover time when a power failure occurs. Power is directly passed through its inverter and the UPS uses a small part of this power to recharge its batteries and conditions the rest of the power to deliver a nearly ideal output,” states Gaurav Burman.
Since online UPS are expensive, they are used for high power consuming and critical loads like servers. “While small offices go for line interactive UPS, big corporate offices always go for online UPS,” says Arun Ghosh, managing director, Hita Technology. “Typically, 3 kVA to 20 kVA are used in small and medium offices and 10 kVA to 120 kVA in large offices,” he adds
Delta Energy Systems has introduced a new range of 1 kVA to 3 kVA UPS system called E–Series, which is suitable for small and medium enterprises and corporate segments. E-Series has microprocessor controlled, high frequency PWM technology, based on ‘true online’ double conversion UPS system with IGBTs at the inverter stage. “It provides pure sine wave output with high reliability and efficiency. It also has input power factor correction resulting in lower electricity bills and minimised harmonics,” informs Deepak Sharma, country business head, UPS, Delta.
Says Venkat Rao, “There is no new topology in the static system as such. However, energy storage devices are witnessing rapid developments in battery, fly wheel, fuel cell and ultra high capacitors.” Emerson’s high efficiency Nxr UPS offers 96 per cent efficiency. Microtek has also introduced E2 energy efficient series of UPS with both internal and external batteries.
Customers are increasingly looking for higher backup time with the need to be increasingly connected for a longer time. They are also looking for a reliable brands as they cannot risk losing data or facing downtime for a long period. They also look for small sized UPS with high efficiency, power saving and user friendly features. According to Yogesh Dua, director, ups.INVERTER.com, buyers look for a product that comes with excellent service support after sale, advance technology with power saving features, updated software support, noise and pollution free, besides being low cost, small sized and user friendly.
Innovation is the trend
Most innovations that are happening are focused on increasing efficiency. This helps in saving power and the environment as well. Conventionally, UPS in small offices offer efficiency up to 85 per cent. But today, UPS are more sophisticated with LCD display, and clean sine wave output. “These systems offer efficiency as high as 94 per cent in sub 10 kVA range. APC has introduced systems that offer 94 per cent efficiency and KW at 0.9 o/P pf. These systems can offer higher power density and can connect more work stations,” says Venkat Rao.
According to Deepak Sharma, the trend is moving more and more towards compact systems and rack based solutions to minimise the space required. “As networks are becoming more complex, far flung and being managed from remote control sites, UPS needs to be equipped with multiple network management protocols and flexible enough to incorporate diagnostics and predictive failure analysis,” explains Deepak Sharma. UPS are now coming with higher capacity chargers, add-on chargers and accessories that provide the user the capability to manage, diagnose and optimise medium to large battery bank installations. “The challenges of flexible capacity enhancements and lowest MTTR (mean time to recovery) demands are best addressed by modular and scalable UPS like Delta NH Plus series,” he adds.
Other latest trends are UPS with LCD panels for user friendly information, IGBT with digital signal processing (DSP), modular UPS and UPS with solar charger, etc. “Microtek develops innovated products from time to time. Customers save money by using our products as we use transformers with less core watt loss,” says Sunil Jain, vice president, public relations, Microtek International.
With the advent of laptops, it was feared that power backup devices will become obsolete but that has not happened. All devices need to be charged using either the USB power of laptops or grid power (which means lower battery backup time). Applications have increased in any office and so has the number of servers that run these applications. All these need backup power. New applications like IP telephone require POE switches that power them to be switched on constantly. “These switches cannot afford even the slightest power fluctuations as the whole data may get damaged. The need of these devices to be constantly connected means using high powered routers that continuously connect servers and users. These cannot afford downtime even for a second and, therefore, need huge power backup. Hence, we can say that with the technological advancement of office applications, power backup systems are also getting modified,” says Venkat Rao.
The current trend is the usage of online UPS and preference is being given to centralised UPS rather than distributed configurations. Customers expect customised solutions rather than standard UPS. Vendors are expected to integrate UPS with batteries, alternate source like DG sets and static/automatic transfer switch, to provide for complete power protection. According to Arun Ghosh, space and cost are the main issues now, hence offices are going for modular UPS. “Solar powered UPS can also reduce the recurring cost,” he adds.
What majors offer
While Luminous offers centralised and decentralised UPS—an office having 20 computers can buy 20 UPS of 600VA or a single unit of 6 kVA, ups.INVERTER.com offers backup solutions like line interactive, pure sine wave UPS, online UPS and UPS with float-cum-boost chargers. Hita interestingly offers solar and wind hybrid power systems. Microtek, on the other hand, claims to be the only company which has a large range of internal and external battery UPS system that can cater to customer requirements of up to 30 kVA
Emerson offers line interactive systems up to 1000 VA which caters up to three work stations and a printer. “Beyond 1 kVA we have online double conversion models, and for 1000 VA to 20000 VA we offer 3 Ph I/P, 1 Ph o/P systems. Beyond this we offer 3 Ph/3 Ph systems,” says Venkat Rao.
APC offers solutions right from small office to large data centres. “Our back-UPS range is tailor made for SOHO and SMB segments, while our ‘Smart-UPS’ solutions are focused on SME and mid level enterprises. We also offer solutions for large data centres including racks, PDU’s and cooling systems,” states Gaurav Burman.
Delta has UPS models catering to specific applications and requirements of the SMB sector. For example, for rating of 1, 2 and 3 kVA, which are widely used by SMB, Delta offers three different product lines—E-Series, N-Series and R-Series. “E-Series UPS are offered for extended backup time up to 24 hours. N-Series is available with inbuilt batteries for backup of 15-20 minutes, which can be further extended. R-Series is for use in standard 19 inch racks for powering servers and network equipment. These are smart systems for mission critical applications, designed for long backup time, easy to start and implement,” informs Deepak Sharma.
What the future holds
With technology advancing in a fast pace, customers are demanding UPS solutions with advanced technology. Brands are also on their toes to upgrade their products. UPS with two new technologies are in use—hybrid topology and fuel cell based UPS systems. Explains Gaurav Burman, “Quite evidently, online technology is not an efficient one while line interactive is not the best mode as it lacks the capability to take care of small fluctuations. A hybrid technology is now being evolved. In this system, the UPS remains in standby mode till the voltage fluctuations are in acceptable preset limits and comes online when needed making it more efficient. Fuel cell based UPS systems are also being developed by some high end research organisations which will use hydrogen as fuel to offer longer backup times. However, it is yet to be declared as a commercial technology.”
According to Deepak Sharma, “Scalable and modular UPS will be more popular in future as it reduces the initial investment for the customer. Rack based UPS solutions are a necessity in most IT environment to minimise the space requirement.”
Electronics Bazaar, South Asia’s No.1 Electronics B2B magazine