Powerpact H and J MCP and Power Factor Correction Capacitors

Issue:
After properly adjusting and troubleshooting for inrush currents, the Powerpact H and J MCP still trips.  Power Factor Correction Capacitors are present.

Product Line:
Motor Circuit Protector

Environment:
Powerpact H and J  MCP and Power Factor Correction Capacitors

Resolution:
The electronic based H and J MCP is capable of tripping much more quickly than traditional electromagnetic technology based MCPs.  The reason for this is to better protect the breaker from very high fault levels and to extend the life of the breaker contacts (and other contacts in the distribution circuit).  This creates, in some specific situations, the need to manage the application of kvar correction capacitors (Reactivar is the Square D brand) to prevent nuisance tripping of the MCP's.

Reason for Tripping:  Capacitor Switching Transients (from back-to-back capacitor switching) and capacitor inrush currents that are higher than the tripping thresholds of the breaker.   These thresholds trip the breaker to avoid excessive contact wear caused by contact "popping" (contacts opening slightly when the inrush current is too high); self-protection.

Potential Solutions:
1.  Replace the electronic MCPs with non-electronic MCP's or thermal-magnetic breakers.
2.  Install inrush-limiting reactors in the capacitor circuits
3.  Modify the configuration of the capacitors: disconnect all capacitors, disconnect all but one capacitor, disconnect all but one capacitor, but re-feed it so that it is always on .  Other configurations may apply.
4.  Add Inductance to Capacitor Wiring, to reduce the magnitude of the capacitor switching transients.

Released for:Schneider Electric Canada