Power Quality Lab

A standard-library electrical engineering project that converts sampled voltage and current waveforms into measurable power-quality evidence.

What it measures

• RMS voltage and current
• Active and apparent power
• Power factor from simultaneous voltage/current samples
• Frequency using interpolated positive-going zero crossings
• Voltage sag, voltage swell, no-load windows, and low-power-factor conditions

Run it

python -m pip install .
power-quality --scenario normal
power-quality --scenario sag

# The module form works without installation from the repository root.
python -m power_quality_lab.cli --scenario normal
python -m power_quality_lab.cli --scenario sag
python -m power_quality_lab.cli --scenario low-pf
python -m unittest discover -s tests -v

Example:

{
  "scenario": "normal",
  "voltage_rms": 120.0,
  "current_rms": 5.0,
  "active_power_w": 563.816,
  "apparent_power_va": 600.0,
  "power_factor": 0.9397,
  "frequency_hz": 60.0,
  "condition": "normal"
}

Classification	Explicit threshold at 120 V nominal
Voltage sag	Below 108 V RMS
Normal voltage	108–132 V RMS
Voltage swell	Above 132 V RMS
No load	Current at numerical zero when voltage is within range
Low power factor	Below 0.80 when voltage is within range

Engineering decisions

• Simultaneous samples preserve the phase relationship needed for active power and power factor.
• Interpolated crossings reduce frequency error compared with using sample indices alone.
• Classification thresholds are explicit and easy to replace with a utility or standards-based profile.
• Synthetic signals are deterministic, making failures reproducible in tests and CI.

Limitations and next hardware step

This repository is a simulation and signal-processing lab, not a certified power-quality instrument. It does not model ADC quantization, sensor isolation, harmonics, calibration drift, or electrical safety. A physical version would require isolated voltage/current sensing, protection, calibration against a trusted meter, and a safe low-voltage test setup before any mains-connected work.