Power quality refers to the ability of electrical equipment to consume the energy being supplied to it. Unfortunately, it is one of the most overlooked aspects of running an electrical installation due to a lack of understanding or awareness of it. This then often leads site and facility managers experiencing problems within their installations to focus on the symptoms rather than the underlying cause of those problems. This can have a number of consequences including higher energy usage and costs, higher maintenance costs, as well as equipment instability and failure.
There are numerous issues to be aware of that can result in major damage. For example, the occurrence of a simple transient voltage that is higher than the breakdown voltage of the insulation in a piece of equipment can cause a flashover, which can lead to the immediate failure of insulation in rotating machines and other equipment.
Harmonic currents also have negative effects on almost all items on the electrical system by upsetting sensitive electronic devices and causing dielectric thermal and mechanical stresses. The most significant of these include computer and other IT equipment crashes and lockouts, flickering lights, electronic card failures in process control equipment, power factor correction equipment failure, high load switching failure, neutral conductor overheating, unexpected circuit breaker operation and inaccurate metering.
Some of these, such as flickering lights and IT equipment crashes are, at the least, an irritant to businesses. Electronic card failures on production lines or process control equipment can cost businesses in unplanned down-time. Worst of all though, failure of power factor correction and electrical distribution equipment, cables, transformers, motors and standby generators can be catastrophic. At the least the presence of harmonics will cause reduced electrical efficiency within the installation and excessive power consumption which you will be paying for.
Voltage dips and swells also should not be ignored. A voltage supply dip can cause particular problems for AC induction motors and with varying severity. The effects of a voltage swell are often more destructive. Regular and sustained voltage swells can lead to early insulation failure in induction motors resulting from increases in current flow and associated overheating. Swells can cause breakdown of components in equipment power supplies over time due to accumulative overload effects. They can also cause damage to electronic components and other sensitive equipment.
Finally, although they are not power quality issues in the same sense as others, voltage imbalance and power factor are also important aspects to consider with regards to a facilities electrical energy consumption and efficiency.
Power Quality issues can be a complex and confusing topic, but it is important to be aware of them. Have a look at our series of articles on Power Quality below. They provide a detailed breakdown of what you need to be aware of in an accessible way and outline what is needed in order to avoid the issues mentioned above.