Power Quality Issue 1

[usman14865]

Hello engineers, I am facing a PQ issue at one of Textile plant having non linear loads, when Switching ON certain stages by Automatic PF relay, the Installed 800 KVAR Passive filter at LV substation creates loud humming noise, overheating of reactors/capacitors and occasional blown fuses, etc, some times no noise is observed if some stages are turned ON manually; due to fear of fire customer has kept it turned OFF, P.F can’t be improved. Panel Analyzer shows THDI before switching Passive filter ON = 9% and after switching passive filter ON = 13% (all 12 stages On. Due to fear of fire customer has kept it turned OFF, P.F can’t be improved.

Does Resonance could still happen at installed anti-resonance passive filter with 7% detuning factor? Is the design of passive filter incorrect? or it has gone incorrect after installation of additional unplanned non-linear loads over a period, or there could be other reasons causing it, we want to avoid expensive AHF solution, opinion from forum members is requested.