Effect of ground current on Power Factor Correction

[vanskat]

I am attempting to realize a stepwise improvement in power factor (0.71 - 0.85) at an aged facility via the installation of capacitors at several low power factor loads. The attempt is to reduce var import from the utility (as well as the other benefits from power factor correction)

Resonance and other issues have been taken into account but I discovered recently that there exists a steady current flow through the system ground conductor.

We were able to identify a few low level ground faults and cut this value in half but I need some thoughts on how this will affect the power factor improvement initiative.

 

[alehman]

If the system is solidly grounded, I don't think it would directly affect the capacitors. You do need to find the souce of the remaining ground current however.

 

[avishai]

Hi vanskat , improving power factor may be very tricky somtimes . As you say you took in consideration resonance and other issues . Did you take in consideration your grounding system ? Do not forget your capacitors are connected between phases so if your supply to the load is a delta one ( three phases + ground no neutral ) then local correction is adequate and thould work but if you have a star supply to the load ( three phases + ground with a connected neutral ) then it is problematic as your neutral line might develop currents resulting from unbalance in the phases and this might lead to problems in grounding as the neutral is grounded . So if you specify wich kind of load it will be possible to help more .

A.Rash BScEE & PE
a_rash@bigfoot.com