DV-Power – FRA500 Sweep Frequency Response Analyzer

Data Sheet


Sweep frequency response analysis (SFRA) is a method to evaluate the mechanical integrity of core, windings, and clamping structures within power transformers by measuring their electrical transfer functions over a wide frequency range.

FRA500 injects a sine wave signal with constant amplitude and variable frequency (user-selectable voltage from 0,2 Vpp to 24 Vpp and frequency from 0,1 Hz to 25 MHz) to one side of a transformer winding. These amplitudes and phase angle values of the reference (output) signal are then compared with the corresponding values of the measured signal (from the second side of the winding). The ratio of the measured signal and reference signal magnitude is graphically displayed in dB through the full sweep frequency.

The response voltage measurement is made across an impedance of 50 Ω. Any coaxial lead connected between the test object terminal and the voltage measuring instrument shall have a matched impedance. To make an accurate ratio measurement, the technical parameters of the reference and response channels of the measuring instrument and any measurement leads shall be identical.

Mechanical or electrical changes in a transformer are detected by comparing their frequency response measurement fingerprints. This comparison can be used to detect power transformer problems such as:

  • Shorted turns or open windings;
  • Winding displacement or deformations;
  • Core movements;
  • Winding connection problems;
  • Broken clamping structures.

A typical test sweep time, with frequency ranging from 20 Hz to 2 MHz, using FRA500 is less than 20 seconds. In addition, there is a “Quick Sweep” feature that allows the user to verify the cable connection integrity and earthing in 10 seconds.

Each FRA500 is delivered with Windows-based Sweep Frequency Analysis (DV FRA) software that can be used to conduct tests and capture data. The software can graphically compare test results as a magnitude vs. frequency graph, in-phase vs. frequency graph, or display both graphs at the same time. The software also provides an analytical tool that can perform correlation coefficients between two traces per the IEEE C57.149 – 2012 or DL/T 911-2004 standard.

DV FRA Software can directly import and playback Doble, Megger, and Omicron SFRA test records allowing the user to compare the FRA500 test records against other devices on the market.

To eliminate the use of long cables FRA500 can be battery-operated (optional) and has a Bluetooth communication feature.