Repeated equipment trips, unexplained shutdowns, overheating motors, fluctuating voltage and irregular electrical behaviour can all indicate a problem within an electrical installation. However, the visible symptom does not always reveal the underlying cause.

Power quality monitoring equipment records what is happening in an electrical system so that contractors, engineers and facility managers can identify disturbances, compare them with equipment failures and make informed decisions about corrective action.

Depending on the device, a monitoring system may measure voltage, current, frequency, power factor, harmonics, phase imbalance, energy consumption, voltage dips, voltage swells and short-duration electrical events. Dedicated power quality analysers can capture more detailed disturbances than conventional meters or basic energy-monitoring devices.

Key takeaways

Power quality problems can include voltage dips, swells, harmonics, transients, interruptions and phase imbalance.
A smart energy meter and a power quality analyser do not perform exactly the same job.
Portable analysers are useful for investigations, while permanently installed equipment supports continuous monitoring.
The correct solution depends on the electrical system, the symptoms being investigated and the level of detail required.
Monitoring equipment provides data; an electrical professional must still interpret the results and determine the appropriate corrective action.

What is power quality monitoring equipment?

Power quality monitoring equipment is used to measure and record the condition of an electrical supply.

An ideal electrical supply should remain reasonably stable and provide equipment with the voltage, frequency and waveform it was designed to use. In practice, switching loads, motors, variable-speed drives, generators, inverters, UPS systems, faulty equipment and external supply disturbances can affect electrical performance.

A power quality monitor helps identify when these disturbances occur, how long they last and which part of the electrical system may be affected.

The term power quality monitoring equipment can refer to several types of device:

Portable power quality analysers
Permanently installed power quality meters
Power quality loggers
Voltage recorders
Energy and power meters
Smart electricity meters
Three-phase monitoring systems
Software and cloud-based monitoring platforms

The appropriate device depends on whether the objective is to investigate a short-term fault, record long-term electrical trends or continuously monitor an entire facility.

Which power quality problems can monitoring equipment detect?

Voltage dips, swells and interruptions

A voltage dip, sometimes called a voltage sag, occurs when the supply voltage falls below its normal level for a short period. A voltage swell occurs when voltage rises above its normal level.

These disturbances may coincide with:

Motors or machinery tripping
Contactors dropping out
Computers or controllers restarting
Lighting temporarily dimming
Variable-frequency drives reporting faults
Sensitive electronic equipment shutting down

Large motors starting, sudden changes in load and disturbances elsewhere in the electrical network can contribute to voltage variation. A suitable analyser can record the voltage level, duration and time of the event, allowing it to be compared with the equipment failure.

Harmonics and waveform distortion

Harmonics are distortions in the normal electrical waveform. They are commonly associated with non-linear loads such as variable-frequency drives, switching power supplies, electronic equipment and UPS systems.

Depending on the installation, excessive harmonic distortion may contribute to overheating, unwanted equipment behaviour and increased loading on certain electrical components.

A dedicated power quality analyser can measure individual harmonics and total harmonic distortion. This is more advanced than simply recording voltage, current or total electricity consumption.

Phase imbalance

In a three-phase electrical system, the load and voltage should be reasonably balanced across the phases.

Excessive voltage or current imbalance can affect motors, transformers and other three-phase equipment. A three-phase monitoring device can compare the electrical values on each phase and help identify unequal loading, a supply problem or an installation fault.

Electrical transients

Transients are fast, short-duration changes in voltage or current. They may be associated with switching events, capacitor banks, lightning or the starting and stopping of large equipment.

Because these events happen very quickly, they may not be visible on a conventional meter. A power quality analyser with waveform-capture and transient-recording capability may be required.

Frequency and power factor

Frequency monitoring helps show whether the electrical supply remains close to its expected operating frequency.

Power factor indicates how effectively electrical power is being used by a load. A low or changing power factor can be useful information when investigating motors, transformers and other inductive equipment.

Many energy meters and smart monitoring systems can measure frequency and power factor. However, measuring these values alone does not make a device a complete power quality analyser.

Power quality analyser vs smart energy meter

These devices overlap in some areas, but they serve different primary purposes.

Equipment type	Typical purpose	Common measurements
Smart electricity or energy meter	Continuous energy usage and load monitoring	kWh, voltage, current, power factor, frequency and power
Power quality logger	Long-term recording and investigation	Voltage, current, power, energy and selected power quality events
Power quality analyser	Detailed troubleshooting and power quality studies	Harmonics, waveforms, dips, swells, transients, imbalance and electrical events

A smart electricity meter is normally chosen when the main objective is to understand how electricity is being consumed, compare loads, review trends or send data to an energy-management platform.

A dedicated power quality analyser is more appropriate when the objective is to investigate disturbances such as harmonics, fast voltage events, waveform distortion or unexplained equipment failures.

The two systems can therefore complement one another. A permanently installed energy meter may identify an unusual trend or recurring change in voltage, current or power factor. A specialist can then use a portable power quality analyser for a more detailed investigation.

Portable vs fixed power quality monitoring equipment

When to use a portable power quality analyser

Portable equipment is generally used for temporary investigations.

It may be installed at a distribution board, machine, motor control centre or other measurement point for a defined period. The recorded data can then be compared with equipment trips, operating schedules and changes in electrical load.

Portable analysers are useful when:

A fault occurs intermittently
A particular machine is suspected
A contractor is conducting a power quality study
Measurements are required at several locations
Detailed waveform or harmonic information is needed

When to install permanent monitoring equipment

A permanently installed system is more suitable when a facility requires continuous visibility.

Fixed monitoring may be useful where:

Electrical performance must be tracked continuously
Several buildings, tenants or production areas are being monitored
Historical information is needed
Alerts or dashboard reporting are required
Energy usage must be compared over time
Multiple meters must report to a central platform

Continuous monitoring makes it easier to establish a normal operating baseline and then identify changes from that baseline.

When does a facility need power quality monitoring?

A facility may benefit from power quality monitoring when electrical problems are recurring, difficult to reproduce or affecting sensitive equipment.

Common warning signs include:

Repeated equipment trips

A breaker, drive, PLC, controller or machine that trips without a clear overload may require further investigation. Monitoring can help determine whether the trip coincides with a dip, swell, current change or another electrical event.

Motors, cables or transformers overheating

Overheating may have several possible causes, including overloading, poor connections, imbalance or harmonic currents. Monitoring data helps narrow down the possible causes before corrective work is selected.

Unexplained electronic failures

Sensitive electronics may react to disturbances that are too fast or too brief to be noticed during an ordinary voltage measurement.

New generators, UPS systems, solar systems or inverters

Alternative power systems introduce additional operating conditions. Monitoring can help show how the installation performs during changeovers, load changes, imports, exports and different supply modes.

Poor or changing power factor

Facilities with large motors or inductive loads may need to monitor power factor over time and across different operating conditions.

Expansion of an industrial or commercial installation

Adding machinery, tenants, production lines or high-power equipment can change the behaviour of an electrical network. Baseline measurements before and after an expansion can assist with planning and troubleshooting.

How to choose the right power quality monitoring system

Define the problem first

Begin by identifying what needs to be measured.

For example:

Is equipment tripping?
Are there suspected harmonics?
Is voltage fluctuating?
Is the objective energy management rather than fault investigation?
Is the problem limited to one machine or spread across the facility?
Does the event happen continuously or only occasionally?

A system selected for energy reporting may not capture a fast transient. Similarly, an advanced portable analyser may be unnecessary when the main requirement is long-term kWh monitoring.

Confirm whether the supply is single-phase or three-phase

The monitoring equipment must suit the electrical system.

For three-phase installations, confirm whether the device can measure each phase individually and whether it can calculate phase totals, line-to-line voltage and line-to-neutral voltage where required.

Decide which measurements are necessary

Possible requirements include:

Voltage
Current
Frequency
Power factor
Active power
Reactive power
Apparent power
Energy consumption
Import and export energy
Harmonics
Total harmonic distortion
Voltage dips and swells
Interruptions
Transients
Phase imbalance
Waveform capture

Do not assume that every monitoring device measures every parameter.

Determine the required monitoring period device measures every parameter.

Determine the required monitoring period

Some electrical problems occur several times a day, while others may happen only once every few weeks.

The system must have sufficient storage, logging capability and event recording to cover the likely investigation period.

Consider communications and remote access

Permanently installed monitoring systems may need to communicate with:

Cloud dashboards
Building management systems
Energy-management software
Industrial control systems
IoT platforms
Local data networks

Common communication options include Modbus RTU, RS485, Ethernet and MQTT, depending on the equipment.

Consider installation and reporting requirements

Before selecting equipment, determine:

Where the device will be installed
Whether it will be portable or permanently mounted
Whether current transformers are required
Who will install and configure it
Who will interpret the information
Whether reports, dashboards or alerts are needed
Whether multiple meters must be connected

Electrical monitoring equipment must be matched to the voltage, current and installation conditions at the site.

Power quality monitoring for industrial and commercial facilities

Manufacturing plants

Factories often operate motors, drives, welders, heaters, compressors and automated production equipment. Monitoring can help correlate electrical disturbances with production stoppages or machinery faults.

Commercial buildings and shopping centres

Commercial properties may have HVAC systems, lifts, lighting, refrigeration, office equipment, generators and multiple tenant loads. Permanent monitoring can provide better visibility across different areas of the property.

Workshops and warehouses

Workshops may experience sudden changes in load as machinery starts and stops. Monitoring can assist with load profiling and the investigation of recurring trips.

Data and telecommunications facilities

These facilities depend on stable electrical power, UPS systems and standby generation. Detailed monitoring may be needed where even a brief disturbance can interrupt equipment operation.

Solar and alternative-energy installations

Monitoring import and export energy, voltage, frequency and load performance can help users understand how a solar or hybrid installation operates under different conditions.

How smart electricity meters support energy monitoring

The UDH-DL Smart Electricity Meter supplied by Repro Supplies is intended for real-time electricity and energy monitoring rather than advanced transient or harmonic analysis.

The system supports single-phase and three-phase applications and can work with compatible Carlo Gavazzi EM and ET series energy meters. Depending on the connected meter and installation, monitored information can include:

Line-to-neutral and line-to-line voltage
Current per phase and total current
Active power
Reactive power
Apparent power
Power factor
Frequency
Import and export kWh
kvarh energy counters

The UDH-DL supports MQTT, Modbus RTU and RS485 communication. Electricity data can be made available to compatible cloud dashboards, IoT platforms and energy-management systems. It can therefore support ongoing monitoring across homes, apart, workshops and industrial environments. citeturn276505view0turn276505view1

Internal-link instruction: Link the words UDH-DL Smart Electricity Meter above to the smart-electricity-meter product page you supplied.

The system can provide useful information about changes in voltage, current, frequency, power factor, load and electricity consumption. However, where detailed harmonic measurements, waveform capture, voltage-event recording or transient analysis are required, a dedicated power quality analyser may still be necessary.

This distinction helps businesses select equipment according to the actual problem instead of expecting one meter to perform every type of electrical analysis.

Questions to answer before requesting a quote

Providing the following information will make it easier to identify a suitable monitoring solution:

Is the installation single-phase or three-phase?
What voltage and current levels are involved?
What equipment or area must be monitored?
What symptoms or electrical problems are occurring?
How frequently does the problem happen?
Is temporary testing or permanent monitoring required?
Is energy consumption or power quality the main concern?
Are harmonic and transient measurements required?
Must the system connect to an existing dashboard or building-management system?
Is MQTT, Modbus RTU or RS485 communication required?
How many meters or measurement points are needed?
Is remote monitoring required?

Frequently asked questions

What does a power quality monitor measure?

Depending on the device, a power quality monitor may measure voltage, current, frequency, power factor, phase imbalance, harmonics, dips, swells, interruptions and transients.

Always check the specifications because entry-level energy meters and advanced power quality analysers do not offer the same measurements.

What is the difference between a power quality analyser and an energy meter?

An energy meter primarily measures electricity usage and load information, including values such as kWh, voltage, current and power.

A power quality analyser is designed for more detailed electrical investigation and may record harmonics, waveform distortion, voltage events, imbalance and transients.

Can power quality monitoring equipment detect harmonics?

Dedicated power quality analysers can measure harmonics and total harmonic distortion. Not every cludes harmonic-analysis capability. citeturn505078search3turn505078search6

Can power quality equipment monitor a three-phase supply?

Yes, provided the equipment is designed and configured for three-phase measurement. The system may need to monitor voltage and current on each phase independently.

Is portable or permanent monitoring better?

Neither is universally better.

Portable equipment is useful for temporary investigations and detailed troubleshooting. Permanent equipment is more suitable for continuous monitoring, historical trends, dashboards and alerts.

Does power quality monitoring reduce electricity consumption?

Monitoring by itself does not reduce consumption. It provides information that can help users identify inefficient loads, poor operating patterns or electrical problems.

Savings depend on what the measurements reveal and which corrective actions are taken.

Can a smart electricity meter replace a power quality analyser?

Not in every application.

A smart meter can provide valuable continuous data about energy usage, voltage, current, power factor and frequency. A dedicated analyser is normally required where detailed harmonics, waveforms, transients or short-duration voltage events must be captured.

Choosing power quality monitoring equipment in South Africa

The correct monitoring solution begins with a clear understanding of the problem.

A facility that needs electricity-usage reporting may require a permanently installed smart energy meter and dashboard. A plant experiencing unexplained trips or equipment failures may need a temporary investigation using a dedicated power quality analyser. Larger sites may benefit from both: continuous energy monitoring combined with specialised testing when an abnormal event is detected.

Repro Supplies can assist businesses, property managers, system integrators and industrial users with smart electricity and energy-monitoring solutions for single-phase and three-phase applications.

Contact Repro Supplies with information about your electrical installation, the equipment being monitored, the measurements required and whether dashboard or IoT integration is needed.

Call Repro Supplies: +27 11 826 5364
Email: info@reprosupplies.co.za

Power Quality Monitoring Equipment in South Africa: A Practical Buyer’s Guide