Appropriate power protection is vital for the effective functioning and continuity of critical business systems. However, most IT engineers/architects often overlook important aspects when designing power protection systems, which can result in costly long term consequences, says Perpetual Power Systems CEO, Mark van Heerden.
In an ideal environment, companies would be able to access clean reliable power. Unfortunately this is not the reality, making power protection systems an important addition to any effective IT system. However, not every organisations power protection, availability factor and business continuity needs are the same.
An organisations power needs are dependent upon the size and type of equipment being supported, the cost of downtime, and the organisation’s availability goals.
“These factors make issues such as lifecycle costs, adaptability, scalability, flexibility, fault tolerance and ease of service more important than ever when selecting appropriate power protection topology. Answering the following five questions can help ensure the power protection system meets application requirements as simply and cost-effectively as possible,” says Van Heerden.
Firstly, companies need to decide on the level of availability that the desired power system is expected to support. There are four basic system architectures, each providing a different level of protection and availability.
Basic protection is typically accomplished through a transient voltage surge suppression (TVSS) and intelligent power distribution unit (PDU) which keep noise and high voltages from reaching the load, preventing equipment damage.
Adding a UPS to the power system provides precision power quality protection against short-term interruptions, fluctuations and anomalies in utility power. It also gives the system the ability to be monitored and provides DCIM tools and software to initiate a controlled shut down in the event that the outage exceeds UPS battery capacity.
A high availability architecture adds redundancy at the UPS level of the system to increase availability. With these systems, maintenance on all system elements can be performed concurrently, eliminating the majority of planned or unplanned downtime.
The highest-level system is a continuous availability fault tolerant architecture, which utilises a dual-bus with distributed redundancy to deliver up to six nines (99,9999%) availability. This system includes two or more independent UPS systems — each capable of carrying the entire load.
The right architecture for a particular application will depend on the cost of down time and the degree of flexibility that exists to accommodate planned downtime for maintenance. Where little time is available for maintenance-related downtime or the cost of downtime is high, a high or continuous availability architecture should be considered.
The second important aspect for IT engineers/architects to consider when designing a power protection system is the life-time costs of the power system. The initial cost of a power system represents only part of the total costs of owning the system.
Initial costs will always play a significant role in the decision-making process; however, organisations are increasingly factoring lifecycle costs into their technology purchasing decisions and need to design for beyond 10 years with flexibility.
Less money spent does not necessary provide the same degree of protection and often the integrity of the system is compromised. Often, savings realised by choosing a less expensive technology are more than offset by increased downtime costs resulting from a lesser degree of power protection or single point of failures. Overall, an online double conversion UPS is more suitable for high availability systems.
Generally the IT systems/ load will determine the design and topology of the power required to support IT systems. These power requirements will also increase over time as higher-density systems are introduced and IT infrastructure expands.
The next important aspect to consider is the impact of the power system on data centre space. The cost per square metre of data centre space is higher than general building space, and increasing equipment densities are putting the squeeze on data centre floor space returns.
Although new generation servers and communication systems are typically smaller than their predecessors, they are almost always more powerful and generate more heat per rack than the systems they replace. Also, the IT and server manufactures do not communicate how efficient their servers are in power usage and often result in unnecessary overdesigning and production of cool air.
For every Watt saved at the component level, results in cumulative savings of about 2,84 Watts in total consumption. The heat density then becomes the key factor in how much floor space is required for each rack or additional cooling.
Another important consideration when developing a power protection system is how the power system will be tested and installed. For lower level systems, testing and installation may not be critical factors to consider, but as system complexity increases, these factors become more important.
High and continuous availability systems are not simply collections of discrete components, they are systems in which all components must work together to ensure seamless operation at the time they are needed most. Ideally, all components in a continuous or high availability power system should be tested together prior to installation to ensure inter-operability under all conditions.
IT engineers also need to consider how the power system will be monitored and maintained. Regardless of manufacturer, UPS and switchgear should be de-energised periodically for preventive maintenance. This usually requires from one to four hours of scheduled equipment downtime. For some organisations this will not be a problem as they have regular windows for scheduled maintenance.
But increasingly IT infrastructures are being asked to support continuous operation, eliminating opportunities to bring down critical systems for support system maintenance. In these cases, the power system needs to be designed in a way that enables maintenance without disrupting power to protected equipment and fault tolerance.
“Failing to consider these key factors can result in a power system with high lifetime costs, unnecessary complexity or poor performance. Understanding the basics of power system design and asking the right questions before equipment is installed can ensure the power system eliminates, rather than adds to, IT concerns,” Van Heerden concludes.