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Filter reactors for low-voltage compensation

Today, an increasing number of harmonics-generating consumers with an inductive load are being used in our networks. Examples include fluorescent lamps, dimmers, speed-controlled drives, three-phase bridge connections and rectifiers.

The harmonic component load and the harmonic distortion of the network are rising as the result. In addition the reactive power is resulting in higher power costs, greater transmission losses and a bigger load on transmission and distribution systems. The capacitors required for near-load compensation and the feeding transformers and network inductances together form a resonant circuit which is made to resonate by the harmonics and can therefore be used to reinforce the harmonics.

The use of filter circuit reactors prevents this physical effect. Using the capacitors the filter circuit reactors are set to a defined series resonant frequency, taking account of an audio frequency ripple control.

Note on the ordering data in version Standard (Catalog LV 60):

Harmonic voltages taken into account according to EN 61000-2-2 for public low-voltage systems and according to EN 61000-2-4 for industrial systems:
110 % mains overvoltage of fundamental wave
6 % of U_Nat 5th harmonic (250 Hz)
5 % of U_N at 7th harmonic (350 Hz)
3.5 % of U_N at 11th harmonic (550 Hz)
3 % of U_N at 13th harmonic (650 Hz)

Filter reactors can be permanently overloaded with 105 %. The filter reactors can be permanently operated with 1.05 times rated current.

There are various reactor series:

• 50 Hz 400 V, reduction factor p = 5.67 %, f_res = 210 Hz, L = constant up to 1.82 I_thmax
• 50 Hz 400 V, reduction factor p = 7 %, fres = 189 Hz, L = constant up to 1.66 Ithmax
• 50 Hz 400 V, reduction factor p = 14 %, fres = 134 Hz, L = constant up to 1.4 Ithmax

If these do not meet your requirements, versions in Standard modified or customized solutions are available. For more information contact "mdexx GmbH" in Bremen.
e-mail: Anfrage@mdexx.com