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Power Quality AnalysisHigh-precision power quality measurement and analsysi

Dewesoft power quality analyzers measure all power quality parameters in compliance with IEC 61000-4-30 Class A standards. Unlike other power quality meters, our analyzers provide a more detailed power quality analysis, including raw data storage, fault behavior analysis, harmonics, and the calculation of additional electrical and also mechanical parameters.



High Voltage

High Voltage

Isolation CAT II 1000 V

Isolation CAT II 1000 V

Isolation CAT III 600 V

Isolation CAT III 600 V



15 MS/s/ch

15 MS/s/ch

5 MHz bandwidth

5 MHz bandwidth

DSI compatible

DSI compatible

TEDS compatible

TEDS compatible









High-speed video

High-speed video

Thermal video

Thermal video

Digital IO

Digital IO

CAN bus

CAN bus







IRIG and GPS timecode

IRIG and GPS timecode

PTP synchronization

PTP synchronization

Touch screen

Touch screen

SD card

SD card

Power Quality Analysis highlights

Harmonics up to 150 kHz

Measure and analyze harmonics for voltage, current, and total harmonic distortion (THD) with frequencies up to 150 kHz. All measurements are carried out according to the IEC-61000-4-7 standards.

THD calculation

Dewesoft power quality analyzers can calculate Total Harmonic Distortion (THD) for both voltage and current up to the 3000th harmonic order.

Interharmonics and higher frequencies

Dewesoft power quality analyzers measure and analyze interharmonics and higher frequencies, grouping higher frequency elements into 200 Hz bands up to 150 kHz.

Flicker, flicker emissions, and RVCs

Dewesoft power quality analyzers automatically calculate flicker and flicker emission parameters in accordance with IEC-61400-4-15 and IEC-61400-21 standards.

Real-time visuals

Fast and customizable visual displays for FFT, Harmonic FFT, and Waterfall FFT provide real-time visual feedback, making this solution an excellent power quality monitor.

Raw data storing

DewesoftX measurement software features an easy-to-use signal processing engine. Math can be performed in real-time during measurement or in post-processing. Dewesoft power quality analyzers store raw data, allowing for parameter recalculation during post-processing.

Flexible configurations

We offer flexible system configurations, from systems with hundreds of input channels to systems with modular and distributable architecture, easy network connectivity, and PTP synchronization. For field use, we provide compact, portable power quality analyzers with built-in displays, CPUs, data storage, and batteries for full autonomy.

Software included

Every Dewesoft data acquisition system is bundled with award-winning DewesoftX data acquisition software. The software is easy to use but very rich and deep in functionality. All software updates are free forever with no hidden licensing or yearly maintenance fees.

Dewesoft quality and 7-year warranty

Enjoy our industry-leading 7-year warranty. Our data acquisition systems are made in Europe, utilizing only the highest build quality standards. We offer free and customer-focused technical support. Your investment into the Dewesoft solutions is protected for years ahead.

What is power quality?

Power quality refers to the stability and consistency of electrical power supplied to equipment. It encompasses various parameters, including voltage, frequency, and waveform characteristics, that ensure electrical devices operate efficiently and reliably. High power quality means that the power supply is free from interruptions, fluctuations, and distortions, which can otherwise lead to equipment malfunctions, reduced efficiency, or even damage.

Why do we need power quality analyzers?

Power quality analyzers (PQAs) are essential tools for assessing and maintaining the quality of electrical power. Here’s why they are important:

  1. Identifying Power Issues: PQAs help in detecting power disturbances such as voltage sags, swells, transients, and harmonics that can negatively affect equipment performance.

  2. Preventing Equipment Damage: By monitoring power quality, PQAs can prevent damage to sensitive electronic equipment caused by poor power conditions, thus prolonging the lifespan of the equipment.

  3. Improving Energy Efficiency: Analyzing power quality helps in identifying inefficiencies and losses in the power system, allowing for corrective measures to improve overall energy efficiency.

  4. Ensuring Compliance: Many industries are required to comply with specific power quality standards. PQAs ensure that power systems meet these regulatory requirements, avoiding potential fines and penalties.

  5. Enhancing Reliability and Performance: Consistent power quality is crucial for the reliable operation of industrial processes, data centers, healthcare facilities, and other critical infrastructure. PQAs help maintain the performance and reliability of these systems.

  6. Data-Driven Decision Making: PQAs provide detailed data and insights into power quality, enabling informed decision-making for maintenance, upgrades, and optimization of power systems.

In summary, power quality analyzers are vital for maintaining the integrity and efficiency of electrical systems, protecting equipment, and ensuring regulatory compliance. They play a crucial role in modern power management and system reliability. Dewesoft power quality analyzers can be used in all the mentioned steps, providing the most flexible power quality analysis solution on the market today.

Introducing the Dewesoft Power Quality Analyzer (PQA)

Dewesoft has combined a rugged hardware platform with high-end signal conditioning and robust software features to create the world’s most capable Power Quality Analyzer (PQA). This instrument opens up entirely new possibilities for engineers performing power quality analysis.

The Dewesoft power quality analyzers can measure all these parameters according to the IEC 61000-4-30 Class A standard. Compared to conventional power quality analyzers, it’s possible to do more detailed analyses (e.g., raw data storing, behavior at faults, calculation of additional parameters, etc.).

Key Features:

  • Comprehensive Power Parameter Calculations:

    • Calculates over 100 power parameters, including P, Q, S, PF, cos phi, and more.

    • Capabilities for full raw data recording.

  • Advanced Analytical Tools:

    • Integrated oscilloscope, FFT, and harmonics analysis.

    • Real-time and post-processing calculation options.

  • Multi-Domain Measurement:

    • Measures data across various domains such as vibration, temperature, strain, loads, GPS/GNSS location data, CAN bus, XCP/CCP, video, and more.

    • Ensures all parameters are fully synchronized, regardless of their update rates.

  • Unmatched Versatility:

    • No other PQA can measure such a broad range of data types with power quality measurements, fully synchronized.

This structured format highlights the key features and benefits, making the information clear and easy to understand.

Advanced data analysis

The Dewesoft Power Quality Analyzer is a highly flexible data acquisition (DAQ) solution that integrates power and energy logging with several other measurement instruments into a single device. This integration offers numerous advantages for the measurement process:

  1. Data Synchronization: Fully synchronized data ensures compatibility and ease of comparison.

  2. Raw Data Logging: Raw data is always stored, allowing for detailed analysis at any time during post-processing.

  3. User-Friendly: Intuitive software simplifies measurement and analysis tasks, making it easy to learn and use.

  4. Cost-Effective: A single instrument that can measure and analyze power parameters, which would typically require multiple devices, saving space, time, and money.

Comprehensive Measurement Capabilities

The Dewesoft Power Quality Analyzer combines several features and offers advanced data analysis capabilities:

  • Harmonics and THD up to 150 kHz

  • Interharmonics and higher frequencies

  • Flicker, Flicker Emissions, and RVCs

  • FFT and waterfall FFTs

  • Scopre and vectorscope

  • Extended symmetrical components

  • Power, efficiency, energy, period values, power of harmonics calculations

Power quality standards overview

Our power quality meters fulfill all the requirements defined in different power quality standards and can thus be used in a wide range of testing applications. The table below sums up the international power quality standards.

IEC 61000-4-30Power quality measurement methods
IEC 61000-4-7General guide on harmonics and interharmonics measurements
IEC 61000-4-15Testing and measurement techniques - Flickermeter
EN 50160Voltage characteristics of electricity supplied by public electricity networks
EN 50163Railway applications - Supply voltages of traction systems
IEEE-519Limits on voltage and current distortion
IEC 61000-2-4Compatibility levels in industrial plants for low-frequency conducted disturbances
IEC 61400-21Measurement And Assessment Of Electrical Characteristics - Wind Turbines
IEC 61400-12Power Performance Of Electricity-Producing Wind Turbines Based On Nacelle Anemometry
FGW-TR3Determination of the Electrical Characteristics of Power Generating Units and systems, Storage Systems as well for their Components in medium-, high- and extra-high voltage grids
VDE-AR4105Power Generating Plants in the Low Voltage Grid
IEC 61000-3-3Limitation of voltage changes, voltage fluctuations and flicker in public low-voltage supply systems, for equipment with rated current ≤16 A per phase and not subject to conditional connection
IEC 61000-3-11Limitation of voltage changes, voltage fluctuations and flicker in public low-voltage supply systems - Equipment with rated current ≤ 75 A and subject to conditional connection
IEC 61000-3-2Limits for harmonic current emissions (equipment input current ≤16 A per phase)
IEC 61000-3-12Limits for harmonic currents produced by equipment connected to public low-voltage systems with input current >16 A and ≤ 75 A per phase

FFT harmonics analysis

Harmonics are integer multiples of the fundamental frequency (e.g., 50 Hz) that distort the voltage and current waveforms. These distortions, caused by non-sinusoidal loads, can negatively impact the operation and lifespan of electrical equipment and devices.

Effects on Motors and Generators:

  • Increased Heating: Harmonic frequencies cause iron and copper losses, leading to excessive heating.

  • Torque Issues: Harmonics can cause pulsating or reduced torque.

  • Mechanical Problems: They create mechanical oscillations and higher audible noise, which accelerate the aging of shafts, insulation, and mechanical parts, reducing efficiency.

Effects on Transformers:

  • Current Harmonics: Increase copper and stray flux losses.

  • Voltage Harmonics: Increase iron losses.

  • Frequency Dependency: Losses are directly proportional to frequency, making higher frequency harmonics more significant.

  • Additional Issues: Harmonics can cause vibrations and increased noise.

Effects on General Electrical Equipment:

  • Reduced Efficiency and Lifespan

  • Increased Heating

  • Malfunctions or Unpredictable Behavior

In summary, harmonics can cause significant issues such as reduced efficiency, increased heating, and potential malfunctions in various electrical equipment and devices. Understanding and analyzing these harmonics is crucial for maintaining optimal performance and longevity.

Harmonics, Interharmonics and THD

The Dewesoft power quality meters can measure harmonics for voltage, current, and additional active and reactive power up to the 3000th order. All calculations adhere to the IEC 61000-4-7 standards.

You can customize the number of sidebands and half-bands for harmonic order calculation. Higher frequency components can be grouped in 200 Hz bands up to 150 kHz.

The system also calculates Total Harmonic Distortion (THD) for voltage and current up to the 3000th order and includes interharmonics to provide comprehensive analysis functionalities.

These advanced harmonic calculation features enable thorough analysis for all types of electrical equipment and devices.

Harmonics calculations

  • U, I, P, Q, and impedance

  • Individual setup of the number of harmonics, including DC component (Example: 20 kHz sampling rate = 200 harmonics @ 50 Hz)

  • Harmonics up to 3000th order (@50 Hz)

  • Variable sidebands and half sidebands for Harmonics

  • Higher Frequencies up to 150 kHz in 200 Hz bands

  • Interharmonics, groups or single values

  • According to EN 61000-4-7

  • Calculation corrected to the actual real frequency

  • THD, THD even, THD odd

  • Trigger on each parameter

  • Background harmonics subtraction

Full FFT analysis

Dewesoft power quality analyzers offer full frequency-based FFT analysis in addition to harmonic analysis. This feature allows for comprehensive frequency analysis across the entire spectrum. You can trigger analyses based on FFT patterns and apply various definable filters, such as:

  • Hanning

  • Hamming

  • Flat top

  • Rectangle

  • And more

For more information about the Dewesoft FFT analyzer, please refer to the following resources:

2D and 3D FFT waterfall analysis

In addition to standard FFT and harmonic FFT analysis, the Power Quality Analyzer also offers 2D and 3D FFT waterfall analysis.

This visualization technique is particularly useful for analyzing variable drives. For instance, when examining the run-up of an inverter, the harmonic sidebands become clearly visible as the frequency increases. The image shows the run-up of an inverter for a traction drive from 0 to 150 Hz.

The FFT waterfall display can be configured to be linear or logarithmic, in 2D or 3D, and sorted by harmonic order or frequency.

Flicker and flicker emission test

Understanding flicker

Flicker refers to fluctuations (repetitive variations) in the RMS voltage between two steady-state conditions. Flicker is often indicated by flashing light bulbs and is particularly common in grids with low short-circuit resistance. It is caused by the frequent connection and disconnection of loads, such as heat pumps and rolling mills, which impact the voltage.

High levels of flicker can be psychologically irritating and harmful to humans.

Flicker measurement with Dewesoft power quality analyzers

Dewesoft Power Quality analyzers provide comprehensive flicker measurement capabilities, including:

  • Measurement of all flicker parameters according to the IEC 61000-4-15 standard.

  • Flicker emission calculation according to the IEC 61400-21 standard, allowing for the evaluation of flicker emissions into the grid caused by wind power plants or other generation units.

  • PST (Short-term flicker severity) and PLT (Long-term flicker severity) with flexible intervals.

  • Individual recalculation intervals.

  • Measure parameters such as Pinst (instantaneous flicker), dU (voltage deviation), dUmax (maximum voltage deviation), and dUduration (duration of voltage deviation).

Rapid voltage changes (RVCs)

Rapid Voltage Changes (RVCs) are additional parameters supplementing the flicker standard. Dewesoft X data acquisition software calculates these parameters according to the IEC 61000-4-15 standard.

RVCs describe any voltage fluctuations where the voltage amplitude changes by more than 3% between two steady states within a certain time interval. These voltage changes can be analyzed in post-processing using various parameters, including:

  • Depth of voltage change

  • dU, dMax, dUduration

  • Steady-state deviation

  • And more

Unbalance and symmetrical components

A balanced system has a 120° phase shift between the voltages and currents, and both voltages and currents have the same amplitude, respectively. Unbalance occurs when the 3-phase system is unevenly loaded, causing the phases and magnitudes to no longer correlate.

To analyze an unbalanced system, the symmetrical components calculation method is used. This method divides the original unbalanced 3-phase power system into three components:

  1. Positive Sequence: Rotates in the same direction as the original system.

  2. Negative Sequence: Rotates in the opposite direction.

  3. Zero Sequence: Represents the system with no phase shift.

An unbalanced system can lead to several issues, including:

  • Current flow in the neutral line

  • Overheating of electrical components

  • Mechanical stress

  • Increased vibration and torque pulsation

  • Low power quality

  • Energy losses

Dewesoft’s power analyzers can measure over 50 parameters for a comprehensive analysis of an unbalanced system. These parameters include various calculations for voltage, current, active power, reactive power, apparent power, and harmonics.

Frequency deviations

The Dewesoft Power Analyzers are ideal for frequency monitoring and testing the frequency behavior of power generation units in the developmental stage (see renewable energy testing).

High-frequency deviations from the fundamental frequency in public grids can have severe consequences. Excessive frequency drops or rises can risk a total power system collapse, potentially causing a blackout.

Frequency deviations in power grids are typically caused by the connection or disconnection of power generation plants or large loads. The grid becomes unstable if there is any deviation from the nominal operating frequency. An excessively high frequency indicates an oversupply of power in the grid, while an excessively low frequency indicates an undersupply of power.

With the growing popularity of renewable energy sources, such as wind and solar, grid stability is more at risk. Wind does not always blow at constant speeds, and solar energy is affected by clouds, shadows, and fluctuations in radiation intensity. These factors lead to abrupt deviations in the frequency at which power is delivered to the grid.

FAQFrequently asked questions

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