Powermode

Recent press headlines such as this have highlighted Eskom’s plight in dealing with the current power crisis in South Africa. Press reports continue to underline the poor shape of the country’s electricity sector in the light of rebounding demand after the global financial crisis.

With Eskom running its generation plants harder than it should, it is unable to initiate regular downtime maintenance. The backlog is growing at an exponential rate.

There seems little chance of the situation changing before Eskom’s new power station units come online in a few years time.

The inevitable result, according to many industry watchers, is power cuts and outages due to plant failures or the forced introduction of downtime for critical maintenance.

To deal with power failures a reliable, standby power supply that works seamlessly to support vital applications, systems and networks during all types of power interruptions is essential.

Reliability is the key consideration that should drive all companies’ investments in backup power systems including generators and uninterruptible power supply (UPS) systems – particularly if these systems back mission critical computer equipment and communication networks.

The longevity, performance and reliability of alternate power systems rest mainly on the quality and frequency of servicing and preventative maintenance undertaken.

My experience in maintaining standby power solutions in large enterprises is that the investment made is only as good as the service it receives. In fact, if you budget a little less on the solution and more on its maintenance you will be rewarded with a significantly more reliability and – overall – cheaper long-term cost of ownership.

Why is this so?  The dynamics of the environment and nature of the equipment are the main factors to be considered. We must remember that a standby power supply is an emergency power solution which, by its very nature, it is not top-of-mind and is normally neglected by branch personnel who are not dedicated to IT or facilities management.

Only when the power grid fails does the standby power system gain in importance in the eyes of staff members who rely on its reliability to continue to function and be productive.

Do they realise that uninterruptible power supply (UPS) systems and generators face challenging operating environments, including high voltages, unstable power ranges, spikes surges and transient voltages?

In the case of generators, intermittent or periodic operation causes stagnation of lubricant and fuel. Diesel engines require regular operation, ideally weekly for 20-30 minutes, to ensure optimum performance.

The environment in a large enterprise plays a large role in standby systems’ reliability. While the data centre at head office is never an issue – it’s designed to provide the optimal environment for the equipment – this is not the case at remote or branch locations such as retail outlets, distribution centres and smaller offices.

Here, in these often smaller and changeable locations, it’s just not feasible – or viable – to install standby power solutions in an ideal, stable operating environment.

In my experience, finding a well-organised, air-conditioned server room in a branch location is a rarity. The norm is that the UPS is located in hot, dusty closets, in storerooms, under a desk, in a hallway or simply next to the printer.

Generators are located outside in a yard, in a parking bay or receiving area and the enclosures are less than secure and open to the elements. Rodents are common companions.

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It is agreed that the African sub-continent is, in general, an emerging economic region and as such lags in terms of infrastructure development compared to the more industrialised  countries of the world.

This is especially true when it comes to power provisioning.  South Africa, although by far the most developed country in the region, is  now beginning to experience the kind of service levels that its more northerly neighbours have had to contend with for some time.

Unreliable power and heavily loaded networks are the cause of unstable and inconsistent power levels.  This is why, for many years, transformer-based UPSs have been standard in the sub-Saharan region north of the Limpopo.

By contrast, South African power consumers have enjoyed relatively stable utility power, enabling the power industry to specify transformer-less UPSs in the ‘volume’ sector of the market – namely UPSs from 10-120kVA.

The advantage of a transformer-less UPS is its compact size, greater efficiency and slightly less cost.  The disadvantage, however, is that it not as robust and does not provide as stable an output – especially where utility power quality is less than ideal.

There is a clear trend towards the adoption of transformer-based UPS technology due to the degradation of utility power in South Africa, especially in more outlying and rural areas.

These industrial strength UPSs, while only slightly less efficient and a bit more bulky, are  more robust and reliable.  Characterised by a transformer isolated inverter output, they are ideal in environments where there is the likelihood of electrical ‘noise’ and transient voltages.

The transformer protects the inverter from load disruption and provides galvanic isolation between input and output.

Modern technology is such that both designs (transformer-less and transformer-based) provide a similar level of performance. The main trade-offs centre on their impact on the upstream power supply and their ability to operate in harsh environments.

So, no longer are these ruggedized units specified only for harsh industrial and mining applications, but now industrial strength UPSs are finding favour in general power protection applications such as data centres, laboratories and offices.

I have read with great interest that the Ekurhuleni Municipality has published a load shedding time-table, supposedly at the behest of Eskom who has warned all its customers of an impending power demand crisis as the country heads into the peak demand winter period.

I also read with amusement that Eskom was quick to deny this claim.  Although admitting that the power grid is “tight”, load shedding could be avoided if “everyone works together”.

This leads one to wonder what exactly was communicated by Eskom to its customers and why it was only Ekurhuleni that reacted.  My personal feeling is that Eskom will do everything it can to avoid using the term “load shedding”.   The previous instance of this in 2008 we all agree was a PR nightmare for the company and indeed, the country as a whole.

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