Understanding Reactive Power: VAR and mVAR
Reactive power is the portion of electricity that oscillates between source and load. It does not do useful work, but it is essential for maintaining voltage levels in AC systems. The standard unit for reactive power is the Volt‑Ampere Reactive, abbreviated VAR. When finer granularity is needed, engineers use the millivolt‑ampere reactive, mVAR, which is simply one‑thousandth of a VAR.
Exact Conversion Factor
The relationship is straightforward: 1 VAR = 1,000 mVAR. This follows the metric prefix “milli,” meaning 10⁻³. The conversion formula is:
mVAR = VAR × 1,000
Why Convert Between VAR and mVAR?
- Precision: Small‑scale devices such as smart meters report reactive power in mVAR to capture subtle variations.
- Compliance: Many standards list limits in mVAR, especially for residential and commercial installations.
- Design: Engineers sizing capacitors or reactors often start with mVAR values before scaling up.
Worked Example: From VAR to mVAR
Imagine a small office has a measured reactive load of 3.75 VAR. To express this in mVAR:
- Identify the factor: 1 VAR = 1,000 mVAR.
- Multiply: 3.75 VAR × 1,000 = 3,750 mVAR.
The office’s reactive demand is therefore 3,750 mVAR. This level can be directly compared to equipment ratings that are often listed in mVAR.
Practical Applications of VAR ↔ mVAR Conversions
Power Factor Correction
Utilities charge penalties for low power factor. Corrective capacitors are sized in kVAR, but the control logic may read sensor data in mVAR. Converting the sensor reading to VAR (or vice‑versa) ensures the right capacitor bank is engaged.
Smart Grid Monitoring
Advanced distribution management systems collect reactive power data every few seconds. The raw data arrives in mVAR to preserve detail, then aggregates to VAR for reporting. Accurate conversion keeps the analytics trustworthy.
Equipment Specification
When selecting a variable frequency drive (VFD), the datasheet may list reactive current in mVAR. Translating that figure to VAR helps compare it with the plant’s overall reactive budget.
Volt Ampere Reactive to Millivolt Ampere Reactive Conversion Table
Each row applies the same rule: multiply VAR by 1,000 to get mVAR.
| Volt Ampere Reactive (VAR) | Millivolt Ampere Reactive (mVAR) |
|---|---|
| 1 VAR | 1,000 mVAR |
| 2 VAR | 2,000 mVAR |
| 5 VAR | 5,000 mVAR |
| 10 VAR | 10,000 mVAR |
| 20 VAR | 20,000 mVAR |
| 50 VAR | 50,000 mVAR |
| 100 VAR | 100,000 mVAR |
| 500 VAR | 500,000 mVAR |
Key Takeaways
Reactive power measured in VAR can be instantly expressed in mVAR by multiplying by 1,000. This simple conversion supports precise monitoring, compliance reporting, and equipment sizing. Whether you are a technician calibrating a sensor or a manager reviewing utility bills, mastering the VAR ↔ mVAR relationship saves time and reduces errors.
Ready to apply these conversions in your projects? Use the table above as a quick reference and keep your reactive power calculations accurate.