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Power Quality (PQ) is the interaction between electrical power and electrical equipment. In simple terms, if your electrical equipment on site operates reliably then your electrical power is of good quality, however, if your electrical equipment suffers malfunctions or is unreliable during normal use then the chances are you have poor power quality.

Power quality problems can be classified as any changes in power, voltage, current or frequency that interfere with the normal operation of electrical equipment.

An Everyday Analogy

Imagine you have a regular banana. It’s not always apparent before you open it whether it is fully ripe and in perfect condition. It is not until you actually peel its skin that you can see the bruises or ripeness of the fruit. We’d all prefer to know beforehand to avoid disappointment and ensure we are getting what we paid for.

The same is true with power quality, you may suffer from poor power quality and not even know it – it’s not until you strip it back and have an audit that you realise something is wrong.

Why is Power Quality Important?

Due to the increasing reliance on electrical equipment across all industries from data centres to retail and manufacturers, the crucial role and sensitive nature that many electronics play in businesses and the number of companies who rely on uninterrupted electronic supply in order to maintain vital business operations, it is imperative that buildings are supplied with clean and reliable power at all times.

Furthermore, low power quality is a contributing factor for rising energy costs and disturbances in production. This is especially troublesome for modern production equipment, which due to its high-tech nature, is sensitive – ironically, it is often this type of equipment that generates the disturbances.

What Problems Can Poor Power Quality Cause?

Some of the most common power quality disturbances are:
  • A distortion and unequal transmission of the normal power waves (Harmonics)
  • A short-term surge of high voltage on the power line for a fraction of a second (Power Spike)
  • Disturbance affecting the electrical circuit due to electromagnetic induction or radiation from an external source (Electromagnetic Interference)
  • A short-term drop of voltage on the power line for a fraction of a second (Power Sag)
  • A very short loss in power, from a fraction of a second up to three seconds in length (Momentary Outage)
  • A long-term drop of voltage on the power line for an extended period, from minutes up to a few days (Brownout)
  • A loss of stability in the normal frequency of the power supply (Frequency Variation)


If your electrical equipment suffers from the problems listed below you need to check the quality of your electrical power:
  • Repeated equipment failure
  • Breakers tripping
  • Fuses blowing
  • Transformers or motors running hot
  • Flickering or blinking lights
  • Unexpected equipment shutdown


What Can a Business do to Address Poor Power Quality?

Maintaining good power quality is a growing concern for many businesses, as whilst the costs on the business that poor power quality inflicts are considerably high, the charges can be somewhat hidden and are therefore often incorrectly attributed to other sources and are never fully eliminated.

1 – Audit

In the first instance, it is always best to get a trained professional to visit your site and perform a full power quality audit.

Power system quality problems can vary with a number of complexities and differing factors, however, quite often the solution relies on going back to basics and on eliminating misapplications. It’s due to the fragility of the process that it is better to hire someone than try and self-diagnose the issue, in addition, many reputable energy management companies will offer a free audit – such as Powerstar. ( An audit will consist of a site visit and power measurement and are usually conducted without any disruption to a facility.

2 – Act

Once an audit has been completed and the problems identified, whoever conducted the audit should produce a personalised proposed solution and implementation plan for your site. In nearly all cases the cost of protecting a building from poor power quality is significantly lower than the costs associated with the problem itself.


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