how to calculate the power to a 3 phase delta connected heater if the load is not bal

Hi guys

I was asked how to calculate the power to a 3 phase delta connected heater if the load is not balanced.
know the formula W = LV x LA x 1.732 x PF for 3 phase power but I can't remember how to do the same for an un-balanced load.

please help me out

No its not sinusoidal current, othervise i think the average power dissipated by the load is calculated from an RMS voltage measurement.

Seen this?
http://www.control.com/thread/1026242303

Kalle

thanks Kalle
I think this link will help,
its kind of same