Clean up your power

It’s estimated that power quality problems cost European businesses €150 billion as a direct result of their electrical power installations not being sufficiently reliable and resilient for today’s and future operating demands.

Even in times of recession it’s surprising how much wasted energy is still visible. Yet, this important issue doesn’t have to be down to indolence or a fait accompli.

There is certainly much to do before 2015 or 2020 (whichever your preferred date from which you wish to work). But both do not allow enough time to deploy nationally the energy saving tasks required to ensure we have the capability to meet the demands of future supply -and the Climate Change Act targets.

The current activity of the SME smart meter rollout, the impending domestic smart meter rollout along with developing a smart grid will certainly help this process. However, further work is essential in buildings, as required under the Building Regulations Conservation of Fuel & Power Part L2.

It doesn’t just have to stop at metering and monitoring 90% of where your energy is going. Organisations should know how it is being used and be aware if there is a problem with their supply or use – it could be costing them more.

Often within organisations there is little, or no, attention paid to determine if the supply and use of electricity is either clean or dirty. If you know it is clean you’re maximising savings but if it is dirty it could be costing you more than you might think.

Every organisation requires reliable, good quality electricity, whether the organisation is in a building with a network of computers, or a manufacturer operating critical and/or industrial equipment. Power quality can be impaired in many ways. For instance, a power outage, over-voltages, dips and surges, poor power factor, transients and harmonic distortion.

These have a variety of causes, but all carry the risk of expensive consequences, such as computer crashes or tripping of circuits that cause loss of data, missed deadlines, production downtime and/or increased maintenance costs.

While power outages or over-voltages may be due to the external electricity supply; usually most instances of poor power quality arise within an organisation’s own infrastructure. For example, transients or harmonic distortion.

Such types of problems with poor power quality originating on site have been steadily increasing. This is largely due to the growing adoption of equipment such as switched-mode power supplies in IT equipment, variable speed drives for electric motors and high frequency lighting in buildings. Other common causes include poor grounding, undersized neutral conductors, non‑linear or unbalanced loads, and uninterruptible power supplies.

The effects of poor power quality are not always obvious. Harmonic distortion can result in currents that are higher than expected, generating nuisance tripping or causing cables or equipment to run at higher temperatures. This can lead to degradation of the cabling infrastructure, which could add an increase of fire resulting from high neutral currents. In addition, this can considerably reduce the lifetimes of expensive equipment such as transformers or motors, and create higher maintenance costs, plus the increased cost of wasted power.

Ensuring good power quality needs sound initial design, constant monitoring and high maintenance standards. Effective monitoring requires the use of high specification power quality analysers, which can monitor up to the 50th harmonic. Strategic placement of power quality analysers on an installation’s electrical distribution network can determine whether a problem exists, and can help with prevention by assisting the planning of any required changes or expansion.

It is not usually necessary to place fully featured power quality analysers on every outgoing supply, since they will often see the same network conditions. However, it is recommended that power quality analysers are fitted at the main distribution points, with individual outgoing supplies monitored by appropriate energy meters. This should be especially so in the case of tenant billing applications where OFGEM or MID approval would be required.

There are international standards that relate to power quality, such as EN50160 and EN61000‑2‑4. These standards give a benchmark, which can be used as the basis for agreement over what can be defined as good or bad power quality. Good power quality analysers and supporting software can make it easy for the user to compare actual performance to the standards.

Power monitoring equipment can provide precise analysis of electrical supply, neutral current measurement and continuous recording of current and voltage. With a built-in web server, it enables data to be sent continuously over a local area network or the Internet – at low cost.

Power quality is a very critical factor in ensuring the safe, efficient and economical operation of industrial, commercial and public sector facilities.

But, having the right tools to fully monitor the power supply is often overlooked.

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