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  Analysis
  • M5200 SFRA
  • M5300 SFRA
• Transformer Diagnostics

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Sweep Frequency Response Analysis (SFRA) Overview

Detect hidden transformer faults using sweep frequency response analysis (SFRA)

Sweep Frequency Response Analysis

Sweep frequency response is a major advance in transformer condition analysis, allowing you to "see" inside transformers without costly detanking.

The standard definition of frequency response analysis (FRA) is the ratio of a steady sinusoidal output from a test object subjected to a steady sinusoidal input. Sweeping through the frequency range of interest gives rise to the S in SFRA, to distinguish it from impulse methods, which estimate the response rather than measure it.

SFRA is a proven technique for making accurate and repeatable measurements. As compared to the “impulse” technique, SFRA is preferred for frequency domain measurements. It covers the full dynamic range and maintains the same energy level for each frequency, providing accurate, consistent results. A high signal-to-noise ratio across the entire 20 Hz to 2 MHz frequency range ensures valid measurements.

Doble M5000 Series

Doble’s M5000 series uses sweep frequency response analysis to detect mechanical failure or movement of windings from short circuits, mechanical stresses, or transportation. The instruments send an excitation signal into the transformer and measure the returning signals. Comparing this response to baseline and other results (such as from similar units) allows you to identify deviations and confirm internal mechanical problems.

Use the M5300 or M5200 Sweep Frequency Response Analyzer to ensure transformer performance, reduce maintenance cost, and increase service life. Both instruments perform the same functions, but the M5300 has a built-in PC and visual display and comes with a laptop keyboard. The M5200 requires an external laptop for operation.

SFRA Software

The M5200 and M5300 come with intuitive, Windows-based SFRA software that runs on a user-supplied PC (for the M5200) or on the M5300 itself. The software allows you to compare and analyzer SFRA measurements. It also comes with preconfigured templates as a guide to specifying tests for the field.

SFRA Resource Center

The Doble SFRA Resource Center is a collection of documents that cover many aspects of transformer frequency response analysis using M5100 SFRA test sets. For access to the SFRA Resource Center, email sfra.info@doble.com

Read an article on the basics of SFRA.

Visit the SFRA User Group