Network Harmonic Studies

VFDs inject harmonics into the grid (network) and may cause “grid pollution”. Therefore, it must be ensured that the harmonic distortion is within defined compatibility limits and does not negatively affect the power quality and especially the functionality of other equipment connected to that grid or even the drive system itself.

⇒ Network harmonic analysis for your peace of mind

We offer network harmonic studies to analyze the harmonic distortion in different operation scenarios and at various grid locations. Moreover, the analysis allows modeling of power cables, capacitor banks, filters and other components that may cause a network resonance.

Our analysis supports following items:

network model based on single line diagram of the site/plant
multiple VFDs inside the plant
modeling of grid resonances (if applicable)
grid impedance scans viewed from selected nodes
modeling of different grid configurations
applying specific harmonic limits (individual and total harmonic distortion)
respecting background harmonics
sensitivity analysis

Furthermore, we have experience with modeling of power cables and their effects and have a database of cable parameters from renowned manufacturers.

Finally, we can suggest mitigation methods in case the harmonic distortion exceeds applicable limits. We always seek for the most economical and robust solution.

Grid models for the network study contain up to 100 nodes, optionally up to 300 nodes. Frequency range to be agreed (typically up to 5 kHz or even 10 kHz upon request)

We recommend to perform a network harmonic analysis in the early stage of the project where there is typically more flexibility to modify some system parameters and improve harmonic performance at low price tag. Later changes are more difficult to incorporate and generally also more costly from end user’s perspective.

Literature

[1] Harmonic calculation versus network harmonic study, https://mb-drive-services.com/harmonic-calculation-versus-network-harmonic-study/