Serie B25

Power factor correction in presence of harmonics

In recent years, Power Factor Correction has evolved greatly due to the presence of generated harmonics by the loads. 

These loads produce harmonic currents and voltage which distorts the network waveforms. The main sources of harmonics are generated by AC/DC static converters and UPS systems. For these reasons it is essential that any installation of Power Factor Correction equipment must be carefully evaluated. 

The possible presence of harmonic currents in the network could create conditions of parallel resonance between the inductance of the network and the capacitors, generating overcurrents and overvoltages, which would cause premature failure of the power factor correction capacitors. The ideal power factor correction solution for any system must be determined by examination of the system parameters and harmonic spectrum.  


- Rated voltage: 400Vac

- Rated frequency: 50Hz (60Hz on request)

- Voltage of auxiliary circuits: 110Vac

- Working temperature range: -10°C/+50°C

- Cubicle: 20/10mm sheet steel, protected against corrosion by a phosphating treatment. Epoxy powder painted, RAL 7035 color (other colors on request) External Protection Degree: IP30 (type S-M), IP40 (Type L) 

- Locking system: by screw for cubicle type S and type M type, by key for cubicle type L

- Ventilation: Forced

- Isolating switch: Three-pole with door interlocking device 

- Supplying: Type S: entry of the cable from the top/bottom, Type M: entry of the cable from the top, Type L: entry of the cable from the bottom

- Wiring: By N07VK CEI 20-22 flame retardant cables. Auxiliary circuits are identified as in the electrical drawing   

- Contactors: Each capacitor banks is controlled by a three-pole contactor. To limit the overcurrent peaks, each contactor is provided with insertion resistors. Rated voltage of auxiliary circuits: 110 Vac, 50 Hz .

- Fuses: Each capacitor banks is protected by a set of three fuses (NH00 type) with high breaking capacity. Also the auxiliary circuits are protected by fuses.

- Capacitors B25 440 Vac Series Single phase of type self-healing, made up of metalized polypropylene, equipped with overpressure safety device and discharge resistor. Filling: biodegradable non toxic dry type, PCB free.  Manufactured using new technologies of metallization. Delta connection. 

- Capacitance tolerance: -5% +10%

- Dielectric losses: <0.3W/kvar 

- Temperature class: -25°C (55°C) 

- Regulators: Varmetric measurement by means of a C.T. (Current Transformer)(secondary 5A) not supplied

- Reference Standards: Complying with: L.V. 73/23 (93/68) EEC Directive, Capacitors: CEI EN 60831-1/2 , Equipments: CEI EN 60439-1, CEI EN 61921-1 

- Options (on request): Automatic switch, Isolator with fuses, Protection degree : IP55, Type M: entry of the cable from bottom, Type L: entry of the cable from the top

Specific References