ORTEA BIORIF SINGLE-PHASE MV CAPACITORS

Ortea BIORIF Capacitors series is complete range of solutions for MV and HV power-factor correction.

They are designed and manufactured using the most modern technologies, ensuring long expected life and high reliability. The Ortea BIORIF series is designed in full compliance with applicable standards (IEC 60871, ANSI, IEEE 18, NEMA CP-1, etc.): they are therefore suitable for installation in any environment or conditions in adherence with the above standards.

Ortea Next makes two types of single-phase capacitors:

  • without internal fuses
  • with internal fuses.

MV capacitors are internally made by connecting in series a number of parallel element groups. In the capacitors with internal fuses, there is a fuse in series to each element which melts and isolates the same in case of dielectric perforation: so capacitors can keep on service with a small output reduction.

In case of capacitors without internal fuses the element perforation short circuits the entire series group at which it belongs, and the capacitors keep on service with an inner fault. The choice of capacitors types depends on bank designer choice and on its power and rated voltage.

Ortea BIORIF Single-Phase MV capacitors without internal fuses

Small capacitors banks are made with single phase capacitors without internal fuses, they are connected in delta and protected by means of HRC limiting current fuses.

Capacitors banks of higher power are made up of at least six single phase capacitors or three split-phase, without internal fuses, with capacitor bank connected in insulated double star and unbalance protection.

In case of capacitors without internal fuses, higher power capacitor banks use one single external expulsion fuse for each capacitor; this fuse, which is specific for power capacitors, is very easy and effective, and it allows an immediate evidence of faulty capacitor.  In these type of banks the number of capacitors is chosen so to allow the bank to keep on service even in the case one capacitor has been insulated by its fuse melting.

An unbalance protection, which works out a lower priority protection, will provide the capacitor bank disconnection after a certain number of capacitors are out of order. Capacitors without internal fuses, which have smaller losses than those with internal fuses, are designed to lower dielectric withstand and are so much more robust and reliable.

As mentioned earlier in these capacitors each capacitive element inside the capacitor has an internal fuse in series. In the event that an element has a fault, the fuse intervenes to exclude the damaged element, without removing the parallel elements from service.

The break of the fuse is very fast (tens of milliseconds) due to energy stored in parallel elements.

Doing so other protection can’t operate and capacitor can stay in service with a small capacitance reduction. The high reliability of these solutions allows to design capacitors with an higher dielectric stress and so units of reduced volume and higher reactive power per volume unity.

CAPACITOR BANKS

Ortea Next proposes Medium Voltage capacitor banks by assembling Ortea BIORIF capacitors along with other components in order to make integrated and completed solutions.

Capacitor banks can be suitable for indoor or outdoor use, with damping reactors, tuned or detuned reactors for harmonic blocking or absorption.

The most adopted scheme is double insulated star with unbalance protection between the two stars, which allows to spot a single capacitor fault.

The bank, depending on type of capacitor, could be also equipped with the following protection means:

  • Expulsion or HRC fuses
  • Capacitor inner fuses

METAL ENCLOSED CAPACITOR BANKS

Ortea Next proposes metal enclosed capacitors banks in many different versions (fixed or automatic, with damping, blocking and absorption reactors).

Fix capacitor banks (with or without main breaker)

The fix banks are mainly adopted for the compensation of steady loads or for fixed portions of the plant required reactive power.

Typical example of the first case is compensation of large MV motors, which are used for large pumping stations, cement or chemical plants. In this case the bank is placed close to the motor and it is wired downstream its main Circuit Breaker, so it is switched on and off along with its motor.

In the second case the capacitor bank is directly connect to the distribution system bus bars.

These types of MV banks are normally divided in two or three or more steps of regulation of the total reactive bank power and they are operated automatically by a power factor correction controller.

Each single step is switched by MV vacuum contactors or Circuit Breaker.

Automatic capacitor banks are available as standard for power up to 5 MVAR and voltage up to 12 kV, both for indoor and outdoor use, and steps from 500kvar to 2000 kvar.