Power Quality Testing Guide: Common Electrical Issues Found During Site Testing
Power quality problems are not always obvious. Electrical equipment may appear to be operating normally while hidden issues within the power supply affect reliability, performance and operating costs.
Voltage dips, harmonics, voltage fluctuations and other electrical disturbances can lead to unexpected equipment faults, nuisance tripping, production interruptions and increased maintenance requirements. Regular power quality testing allows technicians to capture what is happening within an electrical network and identify issues that may not be visible during a standard inspection.
This guide covers some of the most common power quality issues found during site testing and explains how a power quality analyser can help investigate electrical problems.
Why Power Quality Matters
Modern facilities rely on sensitive electronic equipment, automation systems, variable speed drives and other connected technologies that require a stable power supply.
When power quality issues occur, the impact may not always be immediate. Over time, poor electrical conditions can contribute to:
- Unexpected equipment shutdowns
- Nuisance circuit breaker trips
- Reduced equipment lifespan
- Production delays
- Increased maintenance costs
- Difficulty finding the cause of recurring faults
Power quality testing provides a clearer understanding of electrical system performance by monitoring voltage, current, harmonics and other electrical parameters over time.
Common Issue #1: Voltage Dips
Voltage dips occur when the supply voltage temporarily drops below its normal level.
They are commonly caused by:
- Large motors starting
- High inrush currents
- Electrical faults elsewhere on the network
- Sudden changes in load demand
Although voltage dips may only last for a short period, they can still affect sensitive equipment and control systems.
Signs You May Have Voltage Dip Issues
- Equipment unexpectedly restarting
- PLC or automation faults
- Production interruptions
- Frequent alarms or system resets
A power quality analyser can capture voltage events as they occur, helping identify whether voltage dips are contributing to equipment problems.
Common Issue #2: Harmonics
Harmonics are distortions in the electrical waveform caused by equipment that uses electronic switching technology.
Common sources include:
- Variable speed drives
- UPS systems
- LED lighting
- Data centre equipment
- Switch mode power supplies
High levels of harmonic distortion can increase heat within electrical equipment, reduce efficiency and contribute to premature component failure.
Signs You May Have Harmonic Issues
- Overheating transformers
- Hot neutral conductors
- Nuisance breaker trips
- Reduced equipment performance
- Shortened equipment lifespan
Harmonic measurements can help determine whether electrical distortion is affecting system performance.
Common Issue #3: Unbalanced Loads
An electrical system becomes unbalanced when voltage or current levels between phases are significantly different.
This often occurs when loads are unevenly distributed across a facility.
Potential Consequences
- Increased energy losses
- Motor overheating
- Reduced equipment efficiency
- Additional stress on electrical components
Even small imbalances can affect three-phase equipment over time, particularly motors and other critical loads.
Common Issue #4: Excessive Demand Peaks
Many facilities experience short periods where electricity demand increases significantly.
These demand peaks can occur when:
- Multiple large machines start at the same time
- Production schedules overlap
- Temporary equipment is connected
Monitoring demand patterns can help identify when and why peak loads occur.
Benefits of Demand Monitoring
- Better understanding of energy usage
- Improved load management
- Identification of peak demand periods
- More informed energy decisions
Common Issue #5: Intermittent Electrical Events
Some electrical problems only occur occasionally, making them difficult to diagnose during a single site visit.
Examples include:
- Intermittent voltage fluctuations
- Short-duration disturbances
- Unexplained equipment faults
- Recurring production interruptions
Continuous power quality monitoring allows these events to be captured when they occur, providing valuable information for troubleshooting.
The Importance of Power Quality Monitoring
Many electrical problems cannot be identified by taking measurements at one moment in time. A power quality analyser allows technicians to monitor electrical conditions over days or weeks, capturing events that may only happen under certain operating conditions.
The CHK Miro PQ45 Power Quality Analyser can be used for power quality investigations, compliance testing, load monitoring and electrical troubleshooting. It measures key electrical parameters including voltage, current, harmonics, power quality events and waveform disturbances.
This makes it easier to investigate problems such as voltage dips, harmonics, interruptions and other disturbances that may affect equipment reliability.
Recommended Equipment
The CHK Miro PQ45 Power Quality Analyser is designed for detailed electrical investigations where understanding power quality performance is critical. With Class A power quality monitoring capability, the PQ45 helps technicians capture and analyse electrical disturbances, harmonic distortion, voltage variations and other power quality events.
Whether investigating recurring equipment faults, verifying electrical performance or troubleshooting unexplained downtime, the CHK Miro PQ45 provides the data needed to better understand what is happening within an electrical system.
