What Is Power Quality and Why Is It Important?

Power quality refers to how well the electricity delivered to electrical equipment matches the desired characteristics. It is an essential aspect of electrical power distribution and consumption, and it encompasses a wide range of parameters that impact the performance, reliability, and safety of electrical equipment.
In today's digitally-driven world, power quality is more important than ever before. Most electrical and electronic equipment in industries, offices, and homes require high-quality power to function correctly. The efficiency and productivity of equipment depend heavily on power quality.
Poor power quality leads to increased downtime, more fault conditions, and, in some cases, complete equipment failure. In addition, machines that rely on high-quality power run more efficiently, reduce energy waste, and decrease the risk of equipment damage, resulting in a significant reduction of operating costs.

What are the main factors that impact the Power Quality?

The measure of electrical power's capacity to meet the requirements of the devices, is influenced by multiple factors. Here are some of the significant factors:

Voltage Level

Many electronic devices work within a specific voltage range. Variations in the voltage level can cause the equipment to malfunction and cause power quality problems. Low voltages, for instance, can lead to reduced efficiency, and equipment damage, whereas high voltages can cause overheating and even equipment failure.

Unbalanced Voltage

Unbalanced voltage is a power quality issue where the three phases of a three-phase power system have different magnitudes, creating an asymmetrical waveform. This asymmetry can be caused by unbalanced loads, faulty connections, or phase-to-ground faults.
Unequal voltage levels in different phases of the system can cause unbalanced current flow, leading to overheating of equipment and reduced operating efficiency. Negative or zero-sequence components in the voltage waveform can lead to ground fault current flow, causing damage to equipment and creating safety hazards.

Voltage Sag

Voltage sag or dip is a temporary reduction of voltage below the normal level that lasts for a few cycles to a few seconds. It is caused by a sudden increase in load, a voltage drop in the power grid, or a fault in the system.

Voltage Swell

Voltage swell is a temporary increase in voltage above the normal level that lasts for a few cycles to a few seconds. It is caused by sudden changes in load or when a fault on the system is cleared.

Voltage Interruption

Voltage interruption is a complete loss of voltage for a short period of time. It can be caused by a fault in the distribution system or by lightning strikes, and it can last from a few milliseconds to a few minutes. This interruption can cause equipment to shut down or reset, causing damage or data loss.


A flicker is a momentary or sustained variation of voltage characterized by rapid changes in magnitude. It is caused by sudden changes in load, such as the starting of large motors, or by the operation of certain power system equipment like arc furnaces, welding machines, or large drives. The variation in voltage can cause lighting to flicker, which can be noticeable and annoying to occupants. Flicker events are measured by their frequency and depth, and they can impact the performance and lifetime of electronic equipment.

Electrical interference

Interference occurs when noises from other sources, such as other electrical systems, power lines, or even radio transmissions, get mixed in with the electrical signal. Electrical noise can result in signal degradation that can interfere with the equipment's functioning.

Lack of grounding

Grounding refers to connecting an electrical circuit to the earth. This helps ensure stability, reduce noise and interference, and prevent shocks from electrostatic buildup. Without proper grounding, sensitive electronic equipment can malfunction or become damaged.


Harmonics are higher-frequency electrical signals that contaminate the power delivered by utilities to businesses and homes. Electronic devices with nonlinear loads produce harmonics that can interfere with distribution equipment's operation and cause damage to electrical equipment.

Power Factor

Power Factor (cosφ) is the relation between apparent power and active power. Inefficient systems tend to have more apparent power than active power, leading to wastage of energy and possibilities of equipment damages.


Transients refer to sudden and brief fluctuations in voltage or current that occur over a short period of time. They can be caused by events such as lightning strikes, switching operations, or faults in the power system. Transients can range from a few microseconds to several milliseconds in duration, and they can have a significant impact on the operation and reliability of electrical systems and equipment.
Transient voltage surge suppressors, surge protective devices, and other protective measures can be implemented to limit the effects of transients on electrical systems and equipment.

Symbol Image, Lightning Strike (credit Clou)
Symbol Image, Lightning Strike (credit Clou)

How to tackle Power Quality Problems?

There are several ways to overcome power quality problems. Some of the common solutions are:

  • Conduct a power quality analysis
    The first step to overcome power quality problems is to conduct a power quality analysis. This involves measuring power quality parameters such as voltage, current, frequency, and harmonics to identify any adverse power quality events.
  • Implement voltage regulation
    Installing voltage regulation equipment, such as voltage regulators, stabilizers or transformers, can help regulate voltage fluctuations and maintain a stable power supply.
  • Use power conditioning equipment
    Power conditioners, such as surge protectors, uninterruptible power supplies (UPS), and harmonic filters can help to mitigate the effects of power quality issues.
  • Use high-quality electrical equipment
    Using high-quality electrical equipment, such as motors, transformers, and inverters, can reduce the occurrence of power quality problems.
  • Improve grounding and bonding
    Proper grounding and bonding of electrical systems can help to eliminate ground loops and reduce noise and interference.
  • Train personnel
    Training personnel on power quality issues and how to troubleshoot electrical equipment can help to identify and resolve power quality problems quickly.
  • Work with a power quality specialist
    Consulting with a power quality specialist can help to identify potential power quality problems and provide recommendations for resolving them.

Overall, overcoming power quality problems requires a multifaceted approach that includes identifying the root cause of the problem and implementing appropriate corrective measures.


Power quality refers to the level of consistency, reliability, and stability of electrical power. It is important because any deviation from the expected levels of power quality can cause negative consequences such as equipment damage or malfunction, system shutdown, and data loss. Poor power quality can also lead to lower operational efficiency and higher maintenance costs. Understanding power quality issues and taking measures to maintain good quality power is crucial to ensuring sustainable, safe, and efficient utilization of electrical systems and equipment. Our advanced energy meters, AMI-solutions and test equipment can point you in the right direction. Contact us for specific questions.

Editor's note: This article was originally published in April 2023 and has been updated for comprehensiveness.

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