Power Quality and Harmonic Analysis

With the Harmonic Load Flow Calculation and the Frequency Sweep Calculation, the user is able to analyse the modelled network in the frequency domain. The frequency-dependent network impedance offers valuable clues about possible resonances in the network and the effectiveness of countermeasures. The harmonic load flow combines the network impedance with harmonic sources, resulting in the level of the harmonic distortion for each location in the network.

Harmonic Load Flow

  • Harmonic voltage and current indices (IEC 61000-3-6, BDEW 2008)
  • Balanced (positive sequence) and unbalanced (multiphase) model
  • Option to consider n-1 / n-k contingencies1
  • Unbalanced harmonic sources
  • Non-characteristic and inter-harmonics
  • Multiple harmonic injections: current and voltage sources, thyristor rectifiers, PWM-converters, SVS, non-linear loads, Norton-equivalents
  • Background distortion frequency-dependent R and L values
  • Various harmonic distortion indices such as THD, HD, HF, THF, TAD, TIFmx, total RMS currents and voltages, loadings and losses (defined according to IEEE and DIN/IEC standards)
  • Harmonic distortion plot with pre-defined distortion limits according to international standards
  • Waveform plots
  • Calculation of K-Factors and Loss Factors for 2-winding transformers (UL1562, EN 50464-3 (replaces BS7821), EN 50541-2, IEEE C.57.110-1998)

Flicker Analysis

  • Flicker Assessment (IEC 61400-21):
    • Short- and long-term flicker disturbance factor for continuous and switching operations
    • Relative voltage changes
  • Flickermeter (IEC 61000-4-15):
    • EMT or RMS signals
    • Support of multiple file formats as COMTRADE, CSV, user-defined, etc.

Frequency Sweep

  • Automatic step size adaption or constant step size
  • Balanced (positive sequence) and unbalanced network model
  • Option to consider n-1 / n-k contingencies1
  • Self and mutual impedances/admittances (phase and sequence components)
  • Automatic identification of resonances
  • Frequency-dependent R and L values and line/cable models
  • Spectral density of voltage amplitude/angle
  • Risk assessment of sub-synchronous oscillations using radiality factors

Filter Analysis

  • Various filter models
  • Design and layout parameters
  • Filter sizing and verification reports
  • Ripple control analysis


1 Requires Contingency Analysis licence