Harmonic Distortion Calculator
Calculate THD from individual harmonic measurements per IEEE 519.
THD Formula
THD = sqrt(H2² + H3² + H5² + ... + Hn²) / H1 × 100%
Where Hn is the magnitude of the nth harmonic and H1 is the fundamental.
IEEE 519-2022 Harmonic Limits
Voltage Distortion Limits
| Bus Voltage | Individual | THD |
|---|---|---|
| V ≤ 1kV | 5.0% | 8.0% |
| 1kV - 69kV | 3.0% | 5.0% |
| 69kV - 161kV | 1.5% | 2.5% |
| > 161kV | 1.0% | 1.5% |
Current Distortion Limits (Isc/IL 20-50)
| Harmonic Order | Limit (%) |
|---|---|
| h < 11 | 4.0% |
| 11 ≤ h < 17 | 2.0% |
| 17 ≤ h < 23 | 1.5% |
| 23 ≤ h < 35 | 0.6% |
| TDD | 5.0% |