Platform/Active filter sizing

Active filter sizing

Which active filter your installation needs, worked out order by order: each order's 95th-percentile harmonic current and how much of the filter it would consume.

Order by order, not in total

The Active Filter Sizing — Harmonic Compensation module breaks distortion into its harmonic orders and evaluates each separately. A total THD does not let you size anything: two installations with the same THD can need very different filters depending on which orders the distortion sits in.

For each order it reports the period's 95th-percentile current and the share of filter capacity it represents. That table is, quite literally, the sizing sheet.

The 95th percentile is the right basis: sizing on the absolute peak inflates the equipment, and sizing on the average leaves it short in normal operation.

What the table reports

  • Scenario A: filter sized on 95th-percentile distortion
  • Scenario B: filter sized on the period's peak current
  • The harmonic order evaluated
  • That order's current at the 95th percentile, in amperes
  • The share of filter capacity that order takes
  • Results by substation and period
  • Behaviour at the chosen granularity

How it is computed

The module solves two scenarios at once: one sized on 95th-percentile distortion, the other on the period's peak current. Each returns its recommended filter size, and the formula stays on screen so the calculation can be checked.

EVA-Smart AI active filter sizing with two scenarios and allocation by harmonic order
Two sizing scenarios and how filter capacity splits across the ten dominant orders. Here h7 and h5 take 90.8% and 79.8% of capacity: the signature of a six-pulse rectifier, and the reason total THD is not enough to specify from.

Controls

  • Period: the measurement window evaluated.
  • Granularity: the resolution of the harmonic analysis.
  • Substation: the point where the filter would be installed.

What it lets you decide

  • Specify filter capacity backed by measurement.
  • Know which orders the equipment must address and which are irrelevant.
  • Compare quotes on a common technical basis.
  • Assess whether a passive filter solves it before going active.

Size your filter from real measurements

Book an EVA-Smart AI demo and let's review your installation's harmonic spectrum.

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