Simplistically the Neutral Current Trap consists of a ordinary Three Phase core, each limb of which is wound with two copper windings, interconnected in such a way as to significantly reduce the harmful Zero Sequence Harmonics, by trapping the 3rd Harmonic Neutral Currents and thereby lower the high 3rd Harmonic Voltage Distotion.

All or some of the following benefits can be obtained from the Neutral Current Trap :    

Ease of installation (4 terminal connection only)  

Requires little or no maintainence   

Provides an easy and cost effective solution   

Reduces Total Harmonic Distortion   

Reduces Neutral Current and therefore reduces transformer overloading    

Reduces Phase Currents   

Reduces Losses

SPECIFICATION     K Rating 1 - 20

                        Notes

                    1.     The Neutral Current Trap may increase the single line to earth fault currents.

                    2.     The Neutral Current Trap should be used in conjunction with a K rated

                            Harmonic Cancellation Transformer (HCT) to give load

                            isolation and system protection.

                    3.     Wiring impedance will have an effect on the Neutral Current Traps performance.

                            Always place the Neutral Current Trap as close as possible to the load(s)

                            producing the harmonics to reduce this effect.  

                                                                                                   Selection

To select the correct Neutral Current Trap for existing installations the user must first determine the maximum amount of RMS neutral currents. Then select the next highest rating from the table above.

 3rd HARMONIC REJECTION TRANSFORMER CASE STUDY