Essential backup power equipment
September 2017, This Week's Editor's Pick, Security Services & Risk Management, Residential Estate (Industry)
Planning for unexpected power outages has become an essential part of any security strategy. While the primary types of equipment available for supplying backup power haven’t change much in the last few years, continual technological advances mean that some equipment becomes more relevant than others, depending on the subtleties of their operation.
The UPS is the main backup power mainstay, and is differentiated between off-line and on-line models, as Eurobyte Technology’s Neal Thomas describes: “With an off-line UPS, as the name suggests, the inverter module is off-line and does not feed any power to the protected device. The batteries are however connected to the mains power so they stay charged at all times in the event that there is a power failure. Because the inverter module is not feeding power to the protected device, it is not protecting it from other power issues such as power spikes. Once the power goes off there is a slight delay for the inverter to respond, usually between 2 to 10 milliseconds which could adversely affect sensitive electronics.
“An on-line UPS is always on-line and acts as a buffer between the main power and the powered devices. This regulates the electrical flow from the mains to the devices, which also protects them in the event of power spikes and brownouts. Because this unit is always on-line it means there is no switchover time from the UPS once the mains go out and your electronic devices are not affected by any form of a switchover.
“Lastly we have the line interactive UPS, which uses bits of the technologies from both the off-line and on-line UPS. This allows it to function in the same way as an off-line UPS with the difference that it incorporates a voltage regulator which helps to protect devices from more than just power failures, but also against power spikes and brownouts which we experience frequently in South Africa.”
Legrand South Africa is another company that supplies UPSes and related backup power equipment, and the company’s Marius Labuschagne summarises the differences between on-line and off-line models by saying that “Generally on-line UPSes, unlike off-line alternatives, are expensive and inefficient as the inverter is continuously in operation, however it provides better quality of power as compared to an off-line UPS.”
Further exploring inverter technology, Labuschagne explains that the role of the inverter is to take the utility’s pure AC sine wave and convert it into DC in order to charge batteries. The DC is then rectified back into AC, and two main types of rectifiers are available for this step. “Firstly, square wave rectifiers are a cost effective solution to achieve AC. However, the voltage is not ramped on a smooth curve but instead is pulsed on and off at a frequency of 50 to 60 Hz, thus producing a square waveform. Though this technology works well for the majority of electrical goods, unfortunately certain electronics depend on a smooth sine wave and may not function correctly with the square wave.
“This brings us to the second type: the true or pure sign wave rectifier. The advanced electronics used in these are more costly, but the stable waveform offers high-end electronics and sensitive equipment a true, smoothly ramped sine wave.”
When it comes to longer-term power outages, a generator is the go-to solution, and should always be specified at a higher power rating than the UPS that is being used, according to Thomas. “The reason for this is that the generator is running to your devices through the UPS, so if you are using a generator that has a lower power rating you will still be running down the UPS battery and this could cause damage to your UPS, and in turn damage the electronic devices you are trying to power. Also keep in mind that the generator should have a built in voltage regulator to ensure that the power coming through is clean, so as not to damage the electronic devices – this is also where your choice of UPS becomes important.”
As Labuschagne explains it, “the UPS operates from charged batteries and, depending on the autonomy available, can offer a full load supply instantaneously as the mains fail. This gives the generator time to start up and ramp to the required load, at which point it will support the UPS by recharging in order to sustain power. The full UPS load on the generator should be around half to a maximum of two thirds of the full load capacity of the genset. The reason for this is that any switching of equipment on a generator running close to full load may cause dipping and ramping of voltages and frequency as the generator tries to compensate with little reserve. In order to avoid this fluctuation manufacturers recommend 50% to 70% operating loads on gensets.”
Petrol and diesel powered generators have long been the main contenders, but the use of gas generators is now becoming more common. Labuschagne summarises the main differences between the three options as follows: “Gas gensets are silent with clean combustion. They provide moderate power levels and are very expensive to buy, but the running costs are lower. Diesel units are more noisy and the combustion is not clean, however they are more powerful and cost effective to run. Petrol generators provide strong power output and versatility in application, but are less cost effective than diesel and a bit noisy.”
For more information contact:
• Neal Thomas, Eurobyte Technology, +27 (0)21 551 2804, email@example.com, www.eurobyte.co.za.
• Marius Labuschagne, Legrand South Africa, +27 (0)11 444 7971, firstname.lastname@example.org, www.legrand.co.za.
- Awareness and trust in context
November 2017, CA Southern Africa, Access Control & Identity Management, Security Services & Risk Management
Markus Krauss, senior director, Digital Identity and Security, CA Technologies, spoke to Hi-Tech Security Solutions about making identity work for people and things.
- People on the move
November 2017, This Week's Editor's Pick, Access Control & Identity Management, Integrated Solutions, IT infrastructure
Sanjay Dharwadker looks at some of the changes that have been enacted to better manage Europe’s borders.
- Access and identity: looking ahead
November 2017, neaMetrics, ZKTeco, Powell Tronics, This Week's Editor's Pick, Access Control & Identity Management, Integrated Solutions
Access and identity is more important than ever with more options than ever for companies looking for solutions that go beyond mere entry and exit.
- Trusting your privilege
November 2017, Technews Publishing, This Week's Editor's Pick, Access Control & Identity Management, Integrated Solutions
Privileged access management is the starting point for effective enterprise identity and access management, whichever device you're logging in from.
- The access edge
November 2017, Johnson Controls, This Week's Editor's Pick, Access Control & Identity Management, Integrated Solutions, Security Services & Risk Management
With the common denominator of IP networks as their backbone, building automation, security and, in particular, access control systems are increasingly providing opportunities to both security integrators and building managers.
- Facing the future
November 2017, neaMetrics, Virdi Distribution SA, This Week's Editor's Pick, Access Control & Identity Management, IT infrastructure
Facial biometrics is coming into its own today, but is it a 100% reliable means of identity verification and authentication?
- Key management in 2018
November 2017, Zonke Monitoring Systems, Access Control & Identity Management, Security Services & Risk Management
With all the technology available today, you would think we were past using old-fashioned keys for security, but far from it.
- Securing your access security
November 2017, G4S South Africa, Impro Technologies, This Week's Editor's Pick, Access Control & Identity Management, Cyber Security
While one may not consider access control solutions a prime hacking target, any connected device is a target in today’s world.
- Ding dong, it’s IP
November 2017, Elvey, TOA Electronics, Zhejiang Dahua Technology, CAME BPT South Africa, This Week's Editor's Pick, Access Control & Identity Management
IP and open standards have taken the security technology world to a new level where proprietary systems and customer lock-in are no longer the global standard.
- Access a mobile-first world
November 2017, Axis Communications SA, This Week's Editor's Pick, Access Control & Identity Management, IT infrastructure
Mobile access control enables mobile devices – such as smartphones and wearables – to function as credentials in providing access to secured buildings, rooms and areas.
- Why own when you can rent?
November 2017, EOH Security & Building Technologies, Access Control & Identity Management, Security Services & Risk Management
In a rapid changing environment, business is moving away from owning security equipment to a model of serviced rentals.
- Smart cities are built on smart thinking
November 2017, Technews Publishing, This Week's Editor's Pick, Integrated Solutions, IT infrastructure
The smart city concept integrates ICT and various physical devices connected to the network to optimise the efficiency of city operations and services and connect to citizens.