Capacitor Banks in Electrical Construction Works



Capacitor banks help to improve the quality of the electrical power and gives us the more efficient operation of the power system. Capacitor banks are inexpensive if we compare the benefits they deliver to overall power system and can be easily installed anywhere on the network. Automatic Power-factor Correction (APFC) Capacitor Banks also known as Shunt Capacitor Banks (SCB) are installed to provide reactive compensation and power factor correction. The use of APFC improve voltage regulation, saves power loss and improve transmission capabilities.



This article covers the manufacture, supply, installation, testing and commissioning of 415 Volts, 3 phase, 50 HZ, capacitor banks for power factor improvement in building electrification project.

Applicable Standards

The following Indian Standards shall be applicable however, contractor shall comply with the latest or superseded versions of IS/BIS to be used for the complete work: IS 2834 1986 - Shunt capacitor for power system.

APFC Capacitor Banks
APFC Capacitor Banks


Construction of Capacitor Banks

  1. The construction of the capacitors shall be either of mixed dielectric (MD) or metallised polypropylene films (MPP). The dielectric shall be impregnated with non-PCB oil/ flexible epoxy.
  2. The capacitors shall have explosive proof construction and shall be provided with mechanical fuse (below) and induction coils to suppress inrush currents.
  3. The dialectic shall have no losses (less than 0.5 W/KVAr.
  4. The capacitors shall be suitable for overload conditions as follows:
    1. Over voltage - 110% of rated rms. voltage.
    2. Over current - 130% of rated rms. current at rated voltage and frequency.
    3. KVAr - 130% of rated KVAr.
  5. Each unit shall be stand-alone type with terminations brought out of the housing, HRC fuses, jumpers, etc.