A three-phase cable is supplying $800 kW$ and $600 kVAr$ to an inductive load. It is intended to supply an additional resistive load of $100 kW$ through the same cable without increasing the heat dissipation in the cable, by providing a three-phase bank of capacitors connected in star across the load. Given the line voltage is $3.3 kV$, $50 Hz$, the capacitance per phase of the bank, expressed in microfarads, is ________.