Installation of capacitors in low voltage incoming cabinet

What is a capacitor at low voltage?

Capacitors at low voltage are dry-type units (i.e. are not impregnated by liquid dielectric) comprising metallised polypropylene self-healing film in the form of a two-film roll. Self-healing is a process by which the capacitor restores itself in the event of a fault in the dielectric which can happen during high overloads, voltage transients, etc.

What should a capacitor bank have?

The capacitor bank should has two technical drawings, namely, main circuit diagram and control circuit diagram. The main circuit diagram should provide information how to connect the capacitor bank to the supplying switchgear: There is three phase network incoming to supply the capacitor bank (Low Voltage switchgear).

What happens when a capacitor bank is switched into service?

Fig. L39 – Cross-section of cables connecting medium and high power capacitor banks High-frequency voltage and current transients occur when switching a capacitor bank into service. The maximum voltage peak does not exceed (in the absence of harmonics) twice the peak value of the rated voltage when switching uncharged capacitors.

Where should a capacitor bank be placed?

If the capacitor bank is to be placed in the same place as the main switchgear or utility room next to it, IP 20 is enough. Section construction – in a device for reactive power compensation particular sections can be determined, placing them in separate partitions or within the same cubicle. Contents: 1. Enclosure

How to protect a capacitor from a short circuit?

The short circuit protection of the capacitors is provided by the switch disconnectors. For the capacitors the fuse link rated current should be 1.6 time of the rated reactive current of the capacitor. In=Q / (Un×√3) where: Q – rated power of the capacitor at rated mains voltage.

What is the detuning factor of a capacitor bank?

Since the detuning factor for the project was given as p=7%, one knows that the capacitor bank needs to be equipped with reactors. For this reason, some calculations have to be performed, in order to fit the power of the capacitors and its rated voltage taking into account reactive power of a detuning reactors.