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Power Quantities

Time-series of active, reactive, and apparent power with power factor, and a cursor-driven readout across the full recording.

What This Tab Does

The Power tab plots active power (P), reactive power (Q), apparent power (S) and power factor (PF) across the whole recording, then shows the same quantities per phase and three-phase total at the playback cursor in a dense readout grid below the chart.

Two cursors — A (pre-fault) and B (fault / measurement) — can be placed anywhere on the chart. When both are placed, the footer shows the change in P, Q, and PF between them, which is the usual way to quantify what the fault did to the power flow.

This tab requires sign-in. The chart computes over the entire recording once; the readout grid updates continuously as you move the playback cursor.

Power Analysis — panel layout

Power Analysis

L-N

1PQSPF

23φABC

500 / 1000 ms

3φ

47.89 MW

78.37 MVAr

91.84 MVA

0.521lagging

58.6°

12.02 MW

59.26 MVAr

60.46 MVA

0.199lagging

78.5°

−1.87 MW

−8.05 MVAr

8.27 MVA

0.227leading

−103.1°

37.75 MW

27.16 MVAr

46.50 MVA

0.812lagging

35.7°

6cursor 500.0 ms · A 264.0 ms · B 522.0 msΔ (B−A) · ΔP +57.99 MW · ΔQ +87.75 MVAr · ΔPF −0.21

Settings

Cursors

Cursor A

264.0 ms

Cursor B

522.0 ms

A = pre-fault. B = fault / measurement.

Voltage Mode

Phase-GroundLine-Line

Channel Pairing

3 pairs

Phase A

VVA (V)

IIA (A)

Phase B

VVB (V)

IIB (A)

Metric chips:Toggle P, Q, S, and PF on the time-series chart. Highlighted chips are visible traces.

Scope chips:Show 3-phase aggregate or zoom into one phase (A/B/C). Changes both the chart and which lines are drawn.

Settings gear:Open / close the settings sidebar (cursors, voltage mode, channel pairing).

Time-series chart:P (green) and Q (blue) plotted across the full recording. Blue and red vertical lines are cursors A and B; the thin foreground line is the playback cursor.

Readout grid:Values at the playback cursor — 3φ summary row on top, per-phase rows below. Columns: P, Q, S, PF (with lead/lag), and φ.

Δ footer:Reference times plus Δ to the pre-fault reference. Δ = B−A when both cursors are placed, otherwise cursor−A.

Cursor controls:Click a cursor button to arm it, then click the chart to place. Click the chart again to move. Click the button once placed to remove.

Voltage mode + pairing:Switch between Phase-Ground (L-N) and Line-Line (L-L). In L-N, add or edit V/I pairs per phase; in L-L, assign up to three L-L voltages and three phase currents.

Time Playback

The playback slider at the top of the tab lets you animate the readout through time. Press Play to watch the per-phase and three-phase values step through the recording; drag the thumb to scrub to any specific moment. The chart itself is a fixed time-series of the full recording, so what you move is the cursor — the vertical line that drives the readout grid and the Δ in the footer.

The cursor is automatically placed at the start of the recording when a file is loaded, so power values are always available immediately.

Time Playback Slider

123

A4B

545 / 200 ms61x

7Jump to:AB

1Play / Pause: animate through the recording. Phasors, power, harmonics, and readout values update in real time during playback.

2Reset: jump back to the start of the recording.

3Slider track: drag the thumb to scrub to any point in the recording. The filled portion shows current position.

4A/B cursor markers: when dual cursors are placed on the waveform, their positions appear as draggable markers (blue for A, orange for B). Drag a marker to reposition that cursor.

5Time readout: current playback position and total recording duration in milliseconds.

6Speed control: click to cycle through presets (0.5×, 1×, 2×, 4×, 8×). Double-click to type a custom speed. At 1× speed, one power cycle takes one second of wall time.

7Jump to A / B: snap the slider position to cursor A or cursor B. Only visible when both dual cursors are placed.

Chart & Metric Controls

The header above the chart has two groups of chips that control what is drawn:

P · Q · S · PF — metric toggles. Tap a chip to show or hide that trace. P and Q are enabled by default; S and PF are off by default to keep the chart readable. When PF is enabled, a second Y-axis appears on the right of the chart (range 0 to 1).
3φ · A · B · C — scope. $3\varphi$ plots the three-phase aggregate; A, B, or C plots the selected phase only. Only phases you have a configured voltage-current pair for appear as options.

The L-N or L-L pill next to the tab title reflects the current voltage mode. In L-L mode it reads L-L → L-N as a reminder that the displayed phase-to-neutral voltages are derived from the line-to-line measurements.

Cursors A and B

The sidebar has two cursor buttons that place independent time markers directly on the power chart. The workflow is:

Click the cursor A or B button in the sidebar to arm it. The button pulses while armed.
Click anywhere on the chart to place the cursor. It appears as a vertical blue line (A) or red line (B). Clicking the chart again moves the cursor to the new position — the button stays armed so you can fine-tune the placement.
Click the button again once the cursor is placed to remove it. This also disarms the button.

The convention is A = pre-fault (stable load conditions, before the disturbance) and B = fault / measurement (during the fault). Nothing stops you from using them the other way around, but the Δ in the footer is always computed as reference − A, so placing A on a stable point gives the most useful readout.

How Δ is computed

When both A and B are placed, the footer shows Δ (B−A) — a stable snapshot of the change between the two cursors that does not move as you scrub the playback cursor. When only A is placed, the footer shows Δ (cursor−A), which tracks the playback cursor in real time.

Channel Pairing

Power quantities require both a voltage and a current channel. Detego automatically pairs channels based on their phase labels (e.g., V_A with I_A, V_B with I_B). If the automatic pairing is not correct for your recording, open the settings sidebar (gear icon in the top right of the tab) and edit the Channel Pairing section.

Voltage Mode

The sidebar exposes a voltage mode toggle with two options:

Phase-Ground — use when your recording contains phase-to-neutral voltages (e.g., V_A, V_B, V_C). Pair each voltage directly with its corresponding phase current. You can add or remove pairs as needed.
Line-Line — use when your recording contains line-to-line voltages (e.g., V_AB, V_BC, V_CA). Select the available line-to-line voltage channels and phase currents. Detego automatically derives phase-to-neutral voltages from the line-to-line measurements before computing power.

Detego auto-detects which mode to use based on channel names and units. If auto-detection picks the wrong one, you can switch modes manually in the sidebar.

Line-to-Line Configuration

In Line-to-Line mode, you assign up to three line-to-line voltage channels ( $V_{AB}$ , $V_{BC}$ , $V_{CA}$ ) and three phase currents ( $I_A$ , $I_B$ , $I_C$ ).

Only two of the three line-to-line voltages are required. The third is automatically derived using the identity $V_{AB} + V_{BC} + V_{CA} = 0$ .
Any of the three can be the derived one — not just $V_{CA}$ . When two channels are assigned, the dropdown for the third shows “derive from others”.
If all three line-to-line channels are available in the recording, you can assign all three for maximum accuracy.

How derivation works

Detego derives phase-to-neutral voltages from line-to-line using complex phasor arithmetic. The derived voltages contain positive-sequence and negative-sequence components but not zero-sequence, which is inherently absent from line-to-line measurements. See Theory: Line-to-Line Derivation for the full mathematical treatment.

Saving Your Configuration

Channel pairing, voltage mode, metric visibility, and scope are saved automatically per recording. When you reopen a recording, the panel is restored exactly as you left it.

Reading the Readout Grid

Below the chart, the readout grid summarises the values at the playback cursor. The first row is the three-phase aggregate; the rows below it are the individual phases. Columns are:

Column	Unit	What It Tells You
Active Power (P)	W	Real power doing useful work. Positive means power flows from source to load.
Reactive Power (Q)	VAr	Power oscillating between source and load. Positive Q means inductive (lagging); negative Q means capacitive (leading).
Apparent Power (S)	VA	Total power combining active and reactive. This is what determines equipment sizing (transformer ratings, cable ampacity).
Power Factor (PF)	0 to 1	Ratio of useful power to total power. PF = 1 means purely resistive; PF = 0 means purely reactive. Coloured green (≥ 0.95), amber (≥ 0.85), or red (below). The small tag after the number reads leading or lagging.
Phase angle (φ)	degrees	The voltage–current phase angle. Positive for inductive loads, negative for capacitive loads.

Below the grid, the footer strip shows the absolute times of the playback cursor and any placed A/B markers, plus the Δ strip described in Cursors A and B.

Tips

Use the playback slider to scrub through the recording and watch the readout grid update in real time — useful for following P and Q through fault inception and clearance.
Place cursor A in a stable pre-fault region and cursor B during the fault. The footer Δ then quantifies the change in real, reactive, and total power that the fault caused, and does not drift as you move the playback cursor afterwards.
A power factor near 1.0 during a fault suggests a predominantly resistive fault path (e.g., a ground fault through resistance).
Negative active power indicates power flowing from load to source, which occurs during generator reverse power conditions or with distributed generation.
If the panel shows “No voltage-current pairs”, the auto-detection did not find matching channels. Open the sidebar and configure pairs manually.

How it works

For the mathematical definitions of P, Q, S, and power factor, see Theory: Power Quantities.

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