Passive filter of Harmonic

Tuned passive filter

The tuned filter is used in the three-phasepower grid, where the harmonic pollution is more serious, the filer’s target isto eliminate harmonics and reactive power compensation. During the inductivereactive power compensation, voltage quality of the grid also can be improved atthe same time. Particularly in many industrial electric grids, only by theapplication of the tuned filter (also called passive filtering), you cancontrol the harmonic value with the requirements of EN61000-2-2 standard. Thefilter must be tuning design strictly based on the current status of grid for.The resonant frequency of the modules composed filter circuit need be correspondingto the disturbance frequency of the converter.

Filter Designing

It is available of the tunable filter of cabinetstructure with the related voltage of 400V and 690V, and it is usually multiplefilter capacitor and single filter reactor series design, according to the requirementsof special module (single-phase or two-phase, special voltage and frequency), eachfiltered cabinet can be installed up to four filter modules, each moduleincluding following basic elements:

H.R.C fuse breaker

Anti-harmonic capacitor for the highover-current performance and capacity value

Special filter reactor For the higherharmonic current

Thermal protection with a reset button forthe filter reactor temperature monitoring

Air contactor of switching module

The module with Same tuning frequency arein series with the contactor and over current relays (for monitoring module andsingle module current linearization). Depending on the different requirementsof the project, the tunable filter can make the switching operation by manualcontrol or by an external control command of the remote control.

Medium pressure

Injected into the grid

Reactive current

Harmonic currents

Injection of filtering circuit

Filter current

Low Voltage