colosparker said:
Installed Switched Power Factor Correction Capacitors in numerous facilities which have Adjustable Speed Drives throughout the building. Experiencing swelling capacitors, fuse tripping, burning wiring within the Switched PFC units.
As I understand it, if triplen harmonics are present, VA likely increases and thereby decreases power factor. Total PF includes current THD, associated with adjustable frequency motor drives. If any displacement PF is corrected before THD, the existing harmonics could damage capacitor banks.
dPF = WATT/VA*Sqrt(phases)
PF(THD) = Sqrt[1/(1+THD^2)], where THD = current harmonics.
PF(TOT) = dPF * PF(THD)
Before installing displacement corrections, a qualified power-quality engineer should exhaust cost benefits of controlling harmonic-induced overheating, dielectric breakdown in capacitor banks/cables/transformers, or nuisance tripping OCD's, surge suppresser failure, relay malfunctions, and signal interferance in control circuits via common electrode systems/main bondings/transmission lines, or over voltage/excessive currents due to system resonance.
My limited look into system resonance shows it cancels the inductive reactance and capacitance only, not the resistance of the wire. Unlike integrated circuit boards, inside wiring code requires over-current protection sized to conductor circular mills (resistance).
colosparker said:
Experiencing swelling capacitors, fuse tripping
If harmonic induced system resonance can damage unprotected capacitor banks or circuits boards, the inside wiring connected to breakers will remain properly protected.
colosparker said:
..burning wiring within the Switched PFC units
Sever enough tripplen harmanics can still overheat, damage, or set fires with the grounded wires (unprotected by breakers).
My limited look into capacitors shows they correct a dPF lag from inductive reactance, but don't correct harmonics. Harmonic correction would require seperate 120/60v isolation transforers, or 6, 9, & 12 phase wave-canceling transformers, or filters, or perhaps Liebert's interesting all-in-one power conditioners, such as the Datawave magnetic synthesizer.