COMTRADE Viewers Compared (2026)

There are several tools available for viewing and analyzing COMTRADE fault recordings. They range from free web-based viewers to paid desktop applications with advanced protection analysis. Here is an honest comparison of the most commonly used options in 2026.

Quick Comparison

Detego

Detego is a free, browser-based COMTRADE viewer and fault analysis platform. Upload a .cfg + .dat pair or a .cff file and you immediately get interactive waveforms with zoom, pan, dual cursors, and per-channel controls. From there, you can switch to phasor diagrams, symmetrical components, impedance trajectories, power quantities, harmonics, and five protection analysis modules: distance, overcurrent, differential, directional, and fault location.

Detego also computes over 40 derived signals — sequence voltages and currents, superimposed delta quantities, line-to-line voltages, RMS envelopes, and more. A built-in report editor lets you compose PDF reports with drag-and-drop blocks. Cloud storage and read-only sharing links are included for free.

Best for: Protection engineers who need full fault analysis in the browser — phasors, impedance, protection assessment, and reporting — without installing anything.

SIGRA (Siemens)

SIGRA is Siemens' dedicated fault record analysis tool, part of the SIPROTEC engineering suite. It offers six diagram types including time signals, circle diagrams, vector diagrams, and harmonic bar charts. It calculates impedances, RMS values, and symmetrical components, and includes a fault locator. Dual measurement cursors are synchronized across views, and results can be exported to Word, Excel, and PowerPoint.

SIGRA is a paid, licensed product (a 30-day trial is available). It requires a Windows installation. As a Siemens product, it integrates well with SIPROTEC relays but works with any standard COMTRADE file.

Best for: Engineers in Siemens-heavy utilities who need tight integration with the SIPROTEC ecosystem.

TransView (OMICRON)

TransView is OMICRON's software for visualization and analysis of transient recordings. It processes COMTRADE files and calculates derived quantities including impedances, power vectors, RMS values, and symmetrical components. It supports locus diagrams with distance relay zone overlays and can import zone settings via the XRIO format.

TransView is a paid product, typically part of OMICRON's Test Universe suite. It is desktop-only (Windows) and supports COMTRADE 1991 and 1999 formats.

Best for: Engineers already using OMICRON test equipment who want integrated analysis within the Test Universe workflow.

WaveWin

WaveWin is a free desktop COMTRADE viewer that has been around for decades. It is one of the most widely known tools in the industry and supports a broad range of relay-specific file formats in addition to standard COMTRADE. It provides waveform viewing with basic measurement capabilities.

WaveWin does not include phasor diagrams, impedance trajectory plots, or protection analysis modules. It is primarily a waveform viewer and file manager. The interface reflects its age. Installation requires Windows.

Best for: Engineers who need to open proprietary relay formats that other tools don't support.

OscilloViewer

OscilloViewer is a free, browser-based waveform viewer developed by Pragmasoft. It handles .cfg + .dat file pairs and renders interactive time-series charts with channel toggling and zoom. No registration or download is required.

It does not include phasor diagrams, impedance analysis, protection modules, computed signals, or reporting. It is a waveform display tool for quick visual inspection.

Best for: Quick waveform viewing when no analysis is needed.

The Bottom Line

SIGRA and TransView are capable desktop tools with real protection analysis, but both are paid and require Windows installation. Detego offers comparable analysis capabilities — phasors, impedance trajectories, protection assessment, fault location — for free in the browser. WaveWin and OscilloViewer are useful for basic waveform viewing but lack analysis depth.