What Is Power Quality? Common Problems, Causes and Solutions
Power quality refers to the stability, reliability and cleanliness of an electrical supply. Good power quality means that voltage, frequency and waveform remain within acceptable limits so equipment can operate safely, efficiently and without interruption.
Poor power quality can cause downtime, equipment damage, overheating, nuisance tripping, wasted energy and higher operating costs. For businesses using sensitive electronics, variable speed drives, UPS systems, LED lighting, IT equipment or electric vehicle chargers, power quality is now a practical operational issue as well as an engineering concern.
In this guide, we explain what power quality means, the most common power quality problems, what causes poor power quality, how it can be measured and which instruments can help identify the source of the issue.
Why Is Power Quality Important?
Reliable electrical power is essential for maintaining uptime, protecting equipment and controlling energy costs. When the supply is unstable or distorted, electrical systems may continue to run, but they often do so inefficiently and with increased risk of failure.
Power quality problems can affect almost every type of site, including schools, factories, commercial buildings, data centres, healthcare facilities and industrial plants. The impact may be immediate, such as equipment shutting down, or gradual, such as premature wear, overheating and rising energy bills.
In today’s energy-conscious environment, power quality also supports wider business goals such as efficiency, resilience, carbon reduction and compliance with environmental reporting schemes.
Common Power Quality Problems
When power quality issues occur, the symptoms can be wide-ranging. Some problems are obvious, while others remain hidden until equipment fails or energy use increases.
- Voltage sags and swells – short-term drops or rises in voltage that can trip or disrupt sensitive equipment.
- Harmonics and waveform distortion – electrical distortion caused by non-linear loads such as IT equipment, LED lighting, UPS systems and variable speed drives.
- Poor power factor – inefficient use of electrical power, often resulting in higher bills and additional strain on networks.
- Electrical noise – small disturbances that can interfere with sensitive control systems and electronic devices.
- Voltage spikes and transients – sudden surges that can damage electronic components and shorten equipment life.
- Brownouts – prolonged undervoltage conditions that can reduce performance and increase equipment stress.
Each of these problems has a measurable impact. In one school energy audit, triplen harmonics from IT equipment and UPS systems caused neutral conductor heating, while unnecessary out-of-hours loads, including heaters running overnight, wasted thousands of pounds annually.
Read more here: https://cauk.tv/report-to-the-head-teachers-study/.
What Causes Poor Power Quality?
Poor power quality rarely happens by chance. It is usually caused by predictable electrical conditions that can be identified once the system is properly measured and monitored.
One of the most common causes is the growing use of non-linear loads. Equipment such as LED lighting, IT servers, UPS systems, variable speed drives and electric vehicle chargers draws power in irregular patterns. This can distort the electrical waveform and introduce harmonics into the supply.
Harmonics may be invisible during day-to-day operation, but they can increase heating in conductors and transformers, reduce motor efficiency and cause nuisance tripping of protective devices.
Inductive and capacitive loads can also reduce power quality. Motors, compressors, welders and older fluorescent lighting rely on magnetic fields, which can shift the timing between voltage and current. This creates a poor power factor, forcing the site to draw more current than necessary.
External events can also create problems. Lightning strikes, grid switching and fault conditions can cause sudden voltage surges known as transients. These spikes may last only microseconds, but they can damage sensitive electronics, corrupt data and reduce the lifespan of control equipment.
Older infrastructure is another common contributor. Electrical panels, cabling and distribution systems that were suitable decades ago may struggle with today’s mixed electrical loads. Phase imbalance, undersized cables and ageing correction equipment can all create instability, hidden losses and higher maintenance costs.
How Is Power Quality Measured?
Power quality is measured using specialist instruments such as power quality analysers, power loggers and energy loggers. These instruments record electrical conditions over time, allowing engineers to identify patterns, diagnose faults and confirm whether corrective action is needed.
A power quality analyser or logger can measure:
- Voltage
- Current
- Frequency
- Power factor
- Energy consumption
- Harmonic distortion
- Voltage sags and swells
- Transients and spikes
- Load imbalance
As Julian Grant of Chauvin Arnoux UK explains in Power and Energy Logging: “In the energy game, you can’t manage what you can’t measure.”
Read more here: https://cauk.tv/articles/power-energy-logging/.
How to Improve Power Quality
Once power quality issues have been identified, the right solution can be applied. The best approach depends on the cause of the problem, which is why accurate measurement is essential before any corrective action is taken.
- Harmonic filters reduce waveform distortion caused by non-linear loads.
- Power factor correction improves electrical efficiency and can reduce unnecessary energy costs.
- Surge protection helps protect sensitive equipment from voltage spikes and transients.
- UPS systems support critical loads during interruptions and unstable supply conditions.
- Voltage regulators help control sags, swells and brownouts.
- Power quality monitoring provides the data needed to choose the correct solution.
The most effective power quality improvements start with measurement. Once the cause is known, corrective action can be targeted, cost-effective and easier to justify.
The Gold Standard of Electricity
The gold standard of electricity is a stable voltage and frequency delivered through a clean, consistent power supply. Achieving this helps businesses improve efficiency, extend equipment life, reduce costs and protect critical operations.
Good power quality also supports energy management and compliance. Schemes such as Streamlined Energy and Carbon Reporting (SECR) require many UK companies to monitor and disclose energy use, making accurate measurement and reporting increasingly important.
Read more about SECR here: https://cauk.tv/the-streamlined-energy-carbon-reporting-scheme-secr-is-here/.
Real-World Power Quality and Energy Monitoring Case Studies
Each example proves the same point. Only by measuring and monitoring power quality can hidden inefficiencies be identified and corrected.
Chauvin Arnoux Power Quality Analysers and Energy Loggers
Chauvin Arnoux offers a comprehensive range of power quality analysers, power loggers and energy loggers designed to help engineers reveal, monitor and solve electrical supply issues.
PEL51 Power-Energy Logger
The PEL51 is ideal for energy managers and engineers who need compact, easy-to-deploy power and energy logging. It records voltage, current, power and energy values, with Wi-Fi communication for quick access to measurement data.
View datasheet
PEL113 Power Logger
The PEL113 provides comprehensive three-phase monitoring, measuring values including power factor, energy consumption and harmonics. Its flexible connections and network integration make it a strong choice for detailed audits and longer-term monitoring.
Watch: Chauvin Arnoux PEL113 Overview
CA 8345 Power Quality Analyser
The CA 8345 Power Quality Analyser is designed for demanding power quality investigations. It is IEC 61000-4-30 compliant and suitable for diagnosing, monitoring and certifying power quality in industrial, commercial and utility environments.
View datasheet
Benefits of Power Quality Monitoring
Businesses that monitor and improve power quality can gain measurable operational and financial benefits.
- Reduce energy waste.
- Lower operating costs.
- Extend equipment life.
- Improve resilience against rising energy costs.
- Support compliance and reporting requirements.
- Reduce carbon emissions.
- Identify hidden electrical faults before they become expensive failures.
Whether you are managing a school, factory, commercial building or industrial site, power quality monitoring provides the data needed to make informed decisions.
❓ Frequently Asked Questions (FAQ)
Q1: What is power quality?
A. Power quality is the condition of an electrical supply, including the stability of voltage, frequency and waveform. Good power quality allows equipment to operate safely and efficiently.
Q2: What causes poor power quality?
A. Poor power quality can be caused by harmonics, voltage sags, voltage swells, transients, poor power factor, load imbalance, ageing infrastructure and non-linear loads such as LED lighting, UPS systems and variable speed drives.
Q3: How do you measure power quality?
A. Power quality is measured using power quality analysers, power loggers and energy loggers. These instruments record voltage, current, frequency, harmonics, power factor, energy use and other key electrical parameters.
Q4: What are harmonics in electrical systems?
A. Harmonics are distortions in the electrical waveform. They are often caused by non-linear loads and can lead to overheating, reduced efficiency, nuisance tripping and premature equipment failure.
Q5: What is a power quality analyser used for?
A. A power quality analyser is used to detect, record and analyse electrical supply problems. It helps engineers identify issues such as harmonics, voltage events, transients, imbalance and poor power factor.
The Takeaway
Power quality is not optional. It is essential for safe, efficient and reliable electrical operation. By identifying common problems such as voltage sags, harmonics, poor power factor and transients, organisations can reduce waste, protect equipment and improve long-term performance.
Chauvin Arnoux PEL loggers and Class A power quality analysers, including the PEL51, PEL113 and CA 8345, help businesses measure, monitor and master their electricity supply.
Stable voltage, clean waveforms and reliable monitoring are the foundation of safer, greener and more profitable operations.
Isn’t it time your business unlocked the hidden savings in your electrical supply?
CONTACT US TODAY TO DISCUSS POWER QUALITY