High-precision Power Quality Analyzer and Meter

Dewesoft Power Quality Analyzer Highlights

The Dewesoft Power Quality Analyzer is a very flexible DAQ solution that combines power and energy loggers as well as several other measurement instruments into a single device. This has multiple advantages for the measurement process: 

• Data synchronization: data is fully synchronized and compatible for comparison.
• Raw data logging: raw data is always stored and can, therefore, be analyzed at any time in post-processing.
• Easy to use: intuitive software that can perform all the measurement and analysis tasks, meaning the learning curve is much easier to master.
• Low cost: a single instrument that can measure and analyze power parameters that would usually require multiple instruments will save space, time, and money. 

All of this combined makes the Dewesoft power quality analyzer an indispensable piece of equipment that acts as an arsenal of devices able to measure among others: 

• Harmonics and THD up to 150 kHz
• Interharmonics & higher frequencies
• Flicker, Flicker Emissions, RVCs
• FFT, Harmonic FFT, Waterfall FFT
• Symmetrical components

FFT Harmonics Analysis

Harmonics are integer multiples of the fundamental frequency (e.g. 50 Hz) and cause a distortion in voltage and current of the original waveform. Harmonic voltages and currents caused by non-sinusoidal loads can affect the operation and lifetime of electrical equipment and devices.

Harmonic frequencies in motors and generators can lead to increased heating (iron & copper losses), can affect torque (pulsating or reduced torque), create mechanical oscillations, and higher audible noise, which can cause aging of shaft, insulation and mechanical parts and reduce the efficiency.

Current harmonics in transformers increase copper and stray flux losses. Voltage harmonics increase iron losses. The losses are directly proportional to the frequency and, therefore, higher frequency harmonic components are more important than lower frequency components. Harmonics can also cause vibrations and higher noise. The effects of other electrical equipment and devices are very similar and are mainly reduced efficiency and lifetime, increased heating, malfunction or even unpredictable behavior.

Harmonics, Interharmonics and THD

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

You can define the number of sidebands and half-bands for the harmonic order calculation. The higher frequency parts can be grouped in 200 Hz bands up to 150 kHz.

The calculation of THD (overall harmonic content) for voltage and current up to 3000th order and the interharmonics complete the analysis functionalities.

These powerful harmonic calculation functions offer 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 substraction

FFT Waterfall Analysis

Besides the FFT and the harmonic FFT analysis, the Power Quality Analyzer also offers a 2D and 3D FFT waterfall analysis option.

This type of data visualization is especially useful for the analysis of variable drives. For example, looking at a run-up of an inverter, it is clearly visible how the harmonic sidebands originate as the frequency increases. The image depicts the runup of an inverter of a traction drive from 0 to 150 Hz.

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

Rapid Voltage Changes

Rapid Voltage Changes (RVCs) are parameters which are added as a supplement to the flicker standard. Dewesoft X data acquisition software calculates these parameters according to the IEC 61000-4-15 standard.

Rapid Voltage Changes describe any voltage fluctuations which change the voltage amplitude between two steady states more than 3% for a certain time interval. These voltage changes can be analyzed in post-processing using various parameters:

• the depth of voltage change,
• d_u, d_max, d_uduration,
• steady-state deviation,
• Etc.

Frequency Deviations

The Dewesoft Power Analyzer can be used for frequency monitoring and testing frequency behavior of power generation units in the developmental stage (please see renewable energy testing).

High-frequency deviations from the fundamental frequency in public grids can have severe consequences. If the frequency drops or rises excessively there is a chance that the whole power system could collapse causing a blackout.

Frequency deviations in power grids are caused by the connection and disconnection of power generation plants or big loads. The grid becomes unstable if there is a deviation from the nominal frequency at which the grid operates. If the frequency is too high, there is too much power in the grid due to power oversupply. If the frequency is too low, there is too little power in the grid due to power undersupply. As renewable energies especially, wind and solar become more popular, grid stability is more at risk than ever. This is due to the fact that wind does not always blow at constant speeds and that sun energy gets impacted by clouds, shadows, and fluctuations in radiation intensity. This leads to abrupt deviations in the frequency at which power is delivered to the grid.