hi, we have a 2500kVA transformer 13.8kV/480 V system – supplying harmonic loads -2 x 300 kW-6 pulse variable frequency drive and motor at 480 Volts. The system also has one 30 kVA UPS. There is standby 1 x 1250 kVA generator also.
We propose to install harmonic filter however there is no isolator switch on main bus to connect, since UPS tripping is observed during operation of motors.
How to determine the size of active harmonic filter?