Waveform Viewer

The viewer page is divided into several zones — a compact header bar, navigation sidebar, channel list, toolbar, the main chart area, and a bottom recording info bar. The figure below shows the overall layout with numbered callouts for each zone.

When working in analysis tabs like Phasors, Harmonics, or Distance Protection, you often need to cross-reference the raw waveforms. The Waveform Reference Panel provides a collapsible waveform view at the bottom of any analysis tab — no need to switch back to the Waveforms tab.

Opening and Closing

Click the Waveforms icon on the left side of the handle bar to expand the panel to 30% of the screen height. Click it again to collapse. You can also drag the handle up or down to resize the panel freely between 15% and 60% of the available height. Dragging below the minimum snaps the panel shut.

What You See

The reference panel is a full mirror of the Waveforms tab — it shows the same channels, annotations, cursors, computed signals, and zoom level. Any interaction in the panel updates the main viewer state and vice versa:

• Cursor sync — moving the cursor on either the analysis tab or the reference panel updates both
• Zoom sync — if you zoomed into a fault region on the Waveforms tab, the reference panel shows the same view
• Annotations — all annotations are visible in the reference panel (view-only — use the Waveforms tab to create new ones)

Availability

The reference panel appears on all tabs except Waveforms (already showing waveforms), Report, and AI Analysis. The panel's height is remembered as you switch between tabs within the same session.

The Waveform tab displays time-domain plots of all visible channels. The horizontal axis represents time in milliseconds (relative to the trigger point). The vertical axis shows the instantaneous value in the channel's native unit (A, V, etc.).

Analog channels appear as continuous waveform traces. Each channel gets a distinct color based on its phase (A, B, C) or a fallback palette color.

Digital channels appear as binary state bars below the analog traces — high (1) or low (0) — useful for seeing relay operation timing (trip, close, start signals).

Computed signals (created via the Compute tab) are overlaid on the same time axis with their own color scheme.

Hover over a waveform trace to see a tooltip with the channel name, timestamp, and value. Toggle between two modes using the Hover Value Mode button in the toolbar (sine-wave icon with dashed line):

How RMS Mode Works

The RMS is computed over a one-cycle window (20 ms at 50 Hz, 16.67 ms at 60 Hz) ending at the cursor position. All samples within that window are squared, averaged, and square-rooted: RMS = √(Σx²/N). The value updates continuously as you move the cursor — each position produces a fresh calculation. For a pure sinusoid the RMS equals peak / √2 ≈ 0.707 × peak.

Sample Snapping

Both modes snap to the nearest recorded sample — no interpolation between samples. At typical COMTRADE sample rates (1–10 kHz) the gap is 0.1–1 ms, so this is visually imperceptible.

Tooltip Behavior

• In grouped subplot mode, the tooltip shows values for all visible channels in that group
• Values respect the current Primary / Secondary scaling

The secondary toolbar at the top of the chart area contains all interaction tools — zoom, pan, cursors, height adjustments, annotations, and layout controls. When annotation mode is active, a second row of annotation-specific tools appears.

Export visible or all channels as an IEEE C37.111 COMTRADE file. Click the download button in the toolbar to open the export popup.

Key behaviours:

• CFF format — Produces a single .cff file containing the CFG, DAT, and optionally an INF section with embedded annotations. This is the recommended format for sharing because everything is in one file.
• CFG + DAT format — Produces a .zip archive containing separate .cfg, .dat, and (if annotations are included) .inf files.
• Annotation embedding — When "Include annotations" is checked, all annotations (measurement stamps, event markers, text notes, deltas) are serialized into the export. When the file is re-imported into Detego, annotations are automatically restored.
• Computed signals (frequency, RMS envelope, etc.) are included as additional analog channels in the exported file.
• Time-range export adjusts all timestamps relative to the new start time, so the exported file is self-consistent.

The viewer supports two interaction modes, selectable from the toolbar:

Zoom Mode (default)

• Click and drag on the waveform to zoom into a time region
• Double-click to reset zoom to the full recording duration
• Scroll wheel to zoom in/out at the cursor position

Pan Mode

• Click and drag to pan the visible time window left or right
• Scroll wheel still zooms in/out

The current zoom state is preserved when switching between tabs, so you can zoom into a fault region on the Waveforms tab and then switch to Phasors or Harmonics to analyze that same time window.

The left sidebar provides controls for channel visibility:

• Toggle individual channels on/off by clicking the visibility icon next to each channel name
• Group channels by type (voltage/current), by phase (A/B/C), custom groups, or show ungrouped
• Channel colors are indicated by colored dots next to each name

Channel Grouping Modes

The grouping dropdown in the toolbar (Layers icon) controls how channels are laid out as subplots:

Custom Groups

Selecting Custom groups opens the group editor dialog. If you were previously in "Group by type" mode, the auto-detected groups are used as a starting point so you can refine rather than build from scratch.

Inside the editor:

• Each group has a name (auto-generated from its channels, editable) and a list of assigned channels
• Selected channels appear at the top of each group card with a highlighted style and an × to remove
• A dashed divider separates selected channels from the pool of available channels below
• Click a channel in the available pool to add it to the group — it is automatically removed from any other group (each channel can only belong to one group)
• + New Group creates an empty group you can populate
• Ungrouped channels (not assigned to any group) are listed at the bottom and will render as standalone subplots
• Click Apply to save your changes, or Cancel to discard

Custom groups are saved per-recording and restored when you reopen the file.

Y-Axis Scaling

Two scaling modes are available:

• Fit — Each channel is individually scaled to fill its vertical space. Best for seeing waveform shape regardless of magnitude differences.
• Proportional — Channels sharing the same unit (e.g., all current channels in Amperes) share the same vertical scale. Best for comparing relative magnitudes between phases.

The Primary / Secondary toggle in the right side of the toolbar lets you switch how analog channel values are displayed — either in primary (system-side) quantities or secondary (relay-side) quantities.

How It Works

COMTRADE files record each analog channel in either primary or secondary values, indicated by a PS flag in the configuration (fields 11–13 of each analog channel line, added in the 1999 revision). The toggle applies a display-time scale factor using CT (Current Transformer) and VT (Voltage Transformer) ratios so you can view values in whichever convention you prefer without modifying the underlying data.

• Primary — Values as seen on the power system side (e.g., 600 A, 110 kV)
• Secondary — Values as seen at the relay terminals (e.g., 5 A, 110 V)

Global CT and VT Ratios

Click the toggle button to open the ratio editor. If the COMTRADE file includes CT/VT ratios, they are auto-populated and a green Ratios from file badge is shown. If the file does not contain ratios, an amber No ratios in file badge appears and you can enter them manually.

Per-Channel Ratio Overrides

Different channels on the same relay often use different transformer ratios. For example, a neutral current channel (In) may be connected through a 100:1 core-balance CT while the phase channels (Ia, Ib, Ic) use 1500:1 main CTs. Similarly, a neutral voltage channel (Vn) from an open-delta VT may have a different ratio than the phase VTs.

The Per-Channel Ratios section (collapsible, below the global CT/VT fields) lets you set individual ratios per channel. Each row shows:

This section auto-expands when mixed ratios are detected in the file.

Ratio Priority Chain

When converting between primary and secondary, Detego resolves the ratio for each channel using this priority order:

1. Per-channel override — a ratio you set manually in the Per-Channel Ratios section (or imported from device settings)
2. COMTRADE file ratio — the primary/secondary fields embedded in the CFG file for that specific channel
3. Global CT or VT — the single CT or VT ratio at the top of the dropdown
4. 1:1 — no scaling (when no ratio is available from any source)

This means files that already contain correct per-channel ratios (such as ABB REM620 recordings) work correctly out of the box, while files that embed 1:1 ratios (such as Schneider P642 or Siemens recordings) can be corrected manually or via device settings.

Ratio Sources

Per-channel ratios can come from several sources:

• COMTRADE file — many relays embed per-channel ratios in the CFG. When channels have different ratios, they are automatically extracted into per-channel overrides
• Manual entry — edit the per-channel fields directly in the dropdown
• Device settings — if the recording is linked to a device, the device's CT/VT ratios and per-channel overrides are applied as defaults for any recording that doesn't already have saved ratios
• XRIO import — when relay settings are imported via XRIO, the extracted CT/VT ratios (including per-winding CTs for transformer differential relays) are stored on the device and flow through as defaults

What Gets Scaled

The scaling affects all displayed values across the viewer:

• Waveform traces (Y-axis values)
• Cursor readout (instantaneous, RMS, peak values)
• Phasor magnitudes
• Harmonic magnitudes (percentages remain unchanged)
• Annotation measurement values (RMS stamps, amplitude stamps)

Impedance values (V/I ratio) and power quality percentages are scale-independent and remain unchanged.

Tab Sync

CT and VT ratios entered here are automatically synced to other analysis tabs that use transformer ratios:

• Overcurrent tab — CT ratio is populated automatically
• Distance Protection tab — both CT and VT ratios are populated automatically
• Fault Location tab — both CT and VT ratios are populated automatically

A green "Synced" badge appears in those tabs when their ratios match the global values. You can still override ratios per-tab if needed.

Persistence

Per-channel ratio overrides are saved as part of the recording's display configuration. When you reopen a recording, all overrides are restored exactly as you left them. If you link the recording to a device, the device's ratios serve as the initial defaults — but any per-recording overrides you make take precedence.

Single Cursor

Click anywhere on the waveform to place a time cursor. The cursor time appears in the bottom recording info bar as an absolute time (displayed in indigo to match the cursor line color). The left sidebar shows measurement values (RMS, Peak+, Peak−, Instantaneous, Phase) for each channel at the cursor position.

All analysis is performed at the cursor time — phasors, harmonics, impedance, and readout values all update when you move the cursor.

Dual Cursor Mode

Enable dual-cursor mode by clicking the A/B Cursors button in the toolbar (two vertical lines in blue and orange). Click on the waveform to place two independent cursors (A and B). The bottom info bar displays both cursor times (with blue and orange badges) plus the Δt (time difference) between them.

When dual cursors are active, the left sidebar switches to a 7-column layout: InstA, InstB, RmsA, RmsB, ∠A, ∠B, and Δ (delta). The delta column is configurable — click the delta selector in the toolbar to switch between ΔInst, ΔRMS, or Δ∠.

This is useful for measuring fault duration, relay operating time, comparing pre-fault and fault values, or analyzing any time interval.

Time Reference (t₀)

Right-click any cursor to open the context menu with three options:

• Set as time reference — sets the cursor position as the time origin (t₀ = 0). The X-axis relabels to show relative time: points before the reference display as negative, points after as positive. The cursor badge shows a Δ prefix (e.g., "Δ 91.2 ms") to indicate relative time.
• Clear time reference — reverts the X-axis back to absolute recording timestamps. This option is grayed out when no reference is set.
• Remove cursor — removes the cursor (same as pressing Escape).

A dashed vertical line marks the reference point with a small t₀ label at the top. The reference is saved with the recording's display configuration and restored when you reopen it.

This is the standard way power engineers measure relay operating time: set t₀ at fault inception, then read the trip time directly from the cursor as a positive delta.