Fault ID

Overview

The Fault ID tab provides a dedicated, interactive interface for examining classification evidence in detail. While the fault badge on the info bar gives a quick summary, the Fault ID tab shows the full picture: sequence component ratios, angle measurements, step-by-step decision reasoning, and phase-by-phase magnitude comparisons.

The tab activates automatically when a fault is detected in the recording. If no fault is present, it displays a “No fault detected” message.

Panel Layout

The Fault ID tab is divided into seven areas. The timeline and verdict span the top, the evidence strip provides a ratio summary, and the bottom half splits into a decision trail with sector wheel on the left and phase comparison bars on the right. A collapsible settings sidebar sits on the right edge.

Evolving Timeline

The timeline bar at the top of the tab shows how the fault classification changes over the fault duration. Each colored segment represents a period of consistent classification:

• Green — Single Line-to-Ground (SLG)
• Amber — Line-to-Line (LL)
• Red — Double Line-to-Ground (DLG)
• Purple — Three-Phase (3P)

Click any segment dot to select it. The entire tab updates to show that segment's classification evidence. Use the arrow buttons to step through segments sequentially.

Dashed vertical lines mark fault inception and clearance. For auto-reclose recordings with multiple fault events, each event has its own pair of markers, and you can switch between events using the timeline controls.

Verdict Banner

The verdict banner shows the classification result for the selected segment: the fault type name, faulted phases (as color-coded badges), the method used to arrive at the classification, the segment duration, and the number of scan points.

Confidence badges appear when the classification is marginal:

• Moderate confidence (amber) — one or more decision steps were close to a threshold boundary. The classification is likely correct but should be verified.
• Low confidence (red) — a critical decision margin is very small. The classification may be unreliable. Check the Decision Trail for which step is weakest.

The method label shows which algorithm path produced the result: “FIDS angle method” (standard grounded systems), “Beta angle method” (compensated or ungrounded systems), “Voltage fallback” (when angle methods are unavailable), or “Current magnitude ranking” (for DLG phase identification).

Evidence Strip

The evidence strip displays the key sequence component ratios and the classification angle at a glance:

Each metric is color-coded: green when clearly below a threshold, amber when near or above a threshold, and red when strongly elevated.

Decision Trail

The Decision Trail shows every step the classifier took to reach its conclusion, in order. Each step includes the test performed, the measured value, and a status indicator:

• Confirmed — the step passed with a clear margin.
• Identified — an intermediate finding (e.g., “Phase B from FIDS angle”).
• Skipped — the step could not run (e.g., no voltage data).
• Borderline — the measured value is close to the threshold edge.
• Override — a cross-validation check overrode the initial finding.

The final step shows a checkmark with the concluded classification. If transformer coupling is detected (e.g., on delta-star transformer differential recordings), a note appears below the trail explaining which phases are co-phasal and which is anti-phase.

FIDS & Beta Sector Wheel

The sector wheel visualises the angular measurement used for phase identification. It operates in one of two modes:

• FIDS mode (3 sectors) — shows the angle between negative-sequence and zero-sequence current (∠I₂ − ∠I₀). Each 120° sector maps to a single phase (A, B, or C). Used on grounded systems.
• Beta mode (6 sectors) — shows the angle between negative-sequence and positive-sequence current (∠I₂ − ∠I₁). Alternating 60° sectors identify single phases (SLG) and phase pairs (LL). Used on compensated, ungrounded, or high-impedance systems where I₀ is too small for FIDS.

The arrow points to the measured angle; the highlighted sector shows which phase or pair was identified. If the angle falls outside all sectors, the wheel shows “unavailable” and the algorithm falls back to voltage or current magnitude methods.

Phase Comparison Bars

The Phase Comparison panel shows pre-fault and during-fault magnitudes for each phase voltage and current. Horizontal bars make it easy to see which phases are depressed (voltages) or elevated (currents). The percentage change column highlights significant changes in red.

The System footer shows three diagnostics:

• Grounding type — the inferred (or user-overridden) earthing configuration: solidly grounded, low-impedance, high-impedance, compensated (Petersen coil), or ungrounded.
• Z₀/Z₁ ratio — the apparent zero-sequence to positive-sequence impedance ratio, computed from the measured voltages and currents. Typical transmission lines range from 2 to 4.
• Pre-fault unbalance — the negative-sequence component during pre-fault conditions. Values above 2% (amber) or 5% (red) suggest the recording may have been captured during abnormal system conditions.

Classification Settings

The settings sidebar (toggle it with the gear icon on the timeline) lets you override the algorithm's auto-detected parameters: