Harmonics in the grid … what to do?

Increasingly frequent problems caused by high harmonic distortion in an electric network, caused by the growing and essential use of frequency converters, soft starters, electromagnetic induction furnaces, electronic lightings, UPS, etc.
If these problems are not addressed properly mainly cause these effects on the electrical system: transformer saturation voltage drops increase the circulating current through the neutral shot differential overheating in the early exhaustion of the capacitor banks Harmonics can drivers “enter “for two places: 1. from the user’s own installation using load elements” nonlinear “above. 2. On the outer line in the case of transformer share with other users and be these harmonic generators. How should we act? You have to perform a complete measurement of harmonics with a network analyzer to determine:

  • level of harmonic distortion in current and voltage (THDi% / THDu%)
  • type / s of harmonic / s dominant / s
    (both values are very important because they determine the type of three-phase capacitors and inductors that must be used)

Medicion de armónicos

In these cases, what is the solution to the problem?

  • Install a capacitor bank with filters to LOCK and harmonic rejection
  • Install a fixed capacitor filters to LOCK and harmonic rejection to compensate for transformer losses.
  • Install a filter of absorption in the head of the installation to prevent the entry of harmonics coming from outside.
  • Install several absorption filters in each of the harmonic generating lines within the facility itself.

An absorption filter does not replace a capacitor bank, although it owns filters blocking / rejection, and vice versa.