Hello All,

I would like to have an expert opinioin on 'Harmonics Mitigation/Compensation' adopted in IT buildings.

My query is that the nuetral condcutor from main transformer, rising main busduct, upto UPS(located in every floor) and then to the Distribution Boards(DB's) is required to be sized full capacity(100%) as the phase conductor i.e, 4 wire system or alternatively only the neutral conductor from UPS outgoing upto the DB's to be sized full capacity as phase conductor(in that case the the neutral conductor from trasnformer, rising mains and upto the UPS shall be 50% of the phase condcutor(31/2 wire system) and from UPS to DB 100 % of pahse condcutor (4 wire system).

The scheme is LT supply from main transformer secondary is distributed to each floor of the building through a rising main bus duct and the floor panels located at each floor will further distribute power to all lighting and power loads through distribution boards. The UPS will located at each floor (not centralised) will receive power directly form rising mains and then feed the workstations etc through MCB DB's.

Can any one provide details of neutral conductor sizing adopted in IT buildings to mitigate/compensate harmonics due to non linear loads.

Prasanna