TFA THIRD HARMONIC ISOLATION FILTER
Description
In installations with 3rd harmonic generation loads, the current through the neutral cable can be higher than the one in the phases, even in case of balanced loads. The most proper solution for these problems is to use a specific equipment for the 3rd harmonic filtering, consisting basically in a three-phase isolating transformer, delta-star connected, that filters the 3rd harmonic current, plus a passive filter which reduces the 5th harmonic.
Technical Characteristics
Transformador separador/Isolating transformer:
Tensión nominal del primario/ ..........3x400 V
Rated voltage of the primary
Tensión nominal del secundario/ ......3x230 V
Rated voltage of the secondary
Frecuencia/Frequency ........................50 Hz
Conexión del primario/ .....................Triangulo/Delta
Primary connection
Conexión del secundario/ .................Estrella/Star
Secondary connection
Conductor/Wiring ..............................Cobre/Copper
Protecciones/Protections:
Circuito de maniobra/ Control circuit ..Magnetotérmico bipolar 6A
6A bipolar circuitbreaker
Circuito de potencia/ .........................Magnetotérmico tripolar
Power circuit Diferencial/Three-phase
earth leakage switch
(30mA to 300mA)
Temperatura de trabajo/ ..................-10/+40oC
Climatic range
Protección/Protection .........................

Harmonic Filters
These filters are used when the main objective is not the reactive power compensation at the fundamental frequency, but to reduce the harmonic distortion in the supply system.
Among the problems caused by harmonics and which may make their suppression necessary, are the following:
Interferences in telecommunications.
Distortion on the mains voltage.
Disturbances in electronic systems.
Erratic operation of control and protection relays .
Failures in transformers and motors, due to overheating caused by losses on the core.
Overheating of protective fuses to the point where a minor spike on the line causes them to blow.
It should be pointed out that the impedance of all the filters is capacitive below its tuning frequency, whereby they also contribute, even if in a small scale, to the reactive power compensation at the fundamental frequency.
Installation of filters produces a modification on the topology of the electrical supply system. For this reason, the design of filters must be done with regard to an accurate analysis and study of the whole system.
According to the application, there are different types of filters:
3rd harmonic filter HBF-T
Isolation filter
Absortion filter HAF
High pass filter HPF
Active filter SINAF 2.0