Harmonic spectrum calculator — theoretical spectrum and measured-spectrum check
Two modes. Theoretical: enter the pulse number and the fundamental current and the engine returns the characteristic harmonics and the current THD of an ideal converter. Measured check: paste the per-order harmonic currents or voltage contents and the engine compares them, order by order, with the IEEE 519 and GB/T 14549 limits and computes the THD/TDD. A device default spectrum is not offered - use measured or manufacturer data.
Pick a mode first. Theoretical mode needs the pulse number and the fundamental current; measured-check mode needs the PCC voltage level and the per-order measured values.
RequiredRecommendedLeft bar: blue = required, gold = recommended. Optional and advanced fields are collapsed by default.
This is an ideal upper envelope: it assumes a flat DC current, no commutation overlap and ideal switches. A real drive with a DC/AC reactor and filters is well below it. Enter the pulse number; no device default spectrum is used.
A default spectrum for a device type is not provided: that needs measured or manufacturer data. Missing values are shown as Not available, never as zero.
Two different things: (1) the theoretical spectrum is a calculation of the IDEAL converter and is an upper envelope - the limits are often exceeded by an unfiltered 6-pulse drive, which is exactly why the envelope note matters; (2) the measured check compares YOUR values order by order with the standard limits. This page does not do harmonic power flow (needs a full network: see /harmonics and /spectra), does not do resonance scan (see /resonance), and does not cover the device-emission limits of IEC 61000-3-2/-3-12. ER G5/5 per-order planning levels are not loaded (THD planning level only). The result is an engineering check, not a compliance verdict; compliance at the PCC is per the measured record and the planning level published by the local grid operator.
Not calculated yet - press Calculate.
| Not calculated |
Basis: characteristic harmonic orders h = k*p +/- 1 and the amplitude law I_h = I1/h come from ideal p-pulse converter theory (the same basis the platform states in its engine); the closed-form current THD is sqrt(pi^2/(p^2 sin^2(pi/p)) - 1). Limit comparison is 100% reused from engines/harmonic-limits.js: IEEE Std 519-2014 Table 1 / Table 2, GB/T 14549-1993 Table 1 / Table 2 with Annex B, IEC 61000-2-2:2002 and IEC/TR 61000-3-6. The theoretical spectrum is an ideal upper envelope, not a device measurement.
Basis: characteristic harmonic orders h = k*p +/- 1 and the amplitude law I_h = I1/h come from ideal p-pulse converter theory (the same basis the platform states in its engine); the closed-form current THD is sqrt(pi^2/(p^2 sin^2(pi/p)) - 1). Limit comparison is 100% reused from engines/harmonic-limits.js: IEEE Std 519-2014 Table 1 / Table 2, GB/T 14549-1993 Table 1 / Table 2 with Annex B, IEC 61000-2-2:2002 and IEC/TR 61000-3-6. The theoretical spectrum is an ideal upper envelope, not a device measurement.