Mitigation of 3rd harmonic currents in electrical power distribution systems
OwnerMichael Z. Lowensteininventor
Life of this patent
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Abstract
In a multiple phase system for supplying power from an AC source to nonlinear loads, a device for substantially eliminating currents in a neutral wire. The device includes a completely-passive parallel resonant circuit having three passive electrical branches connected in parallel tuned to a third harmonic frequency of the AC source. The three branches comprise a first branch consisting of a capacitor, a second branch consisting of a reactor, and a third branch consisting of a resistor. The resonant circuit is connected to the neutral wire.
Claims20
In a multiple phase electrical distribution system for supplying power from an AC source to one or more nonlinear loads connected to at least one phase line therein, a device for substantially eliminating currents in a neutral wire, said device comprising:
- a completely-passive parallel resonant circuit having three passive electrical branches connected in parallel;
- said first completely-passive parallel resonant circuit having an almost infinite impendence at a third harmonic frequency of a fundamental frequency of said AC source to prevent the formation of only said third harmonic frequency and no other frequency so that there is no third harmonic frequency to remove or dissipate as heat;
- said three passive electrical branches comprise a first branch consisting of a capacitor, a second branch consisting of a reactor, and a third branch consisting of a resistor;
- and
- said completely-passive parallel resonant circuit being electrically connected to said neutral wire, whereby said device is bi-directional in that said system is free of said third harmonic frequency both toward said nonlinear loads and back to said AC source.
An electrical system for supplying power to one or more nonlinear loads connected to at least one phase line of a multiple phase distribution system, comprising:
- a delta-wye transformer;
- a completely-passive parallel resonant circuit having three passive electrical branches connected in parallel;
- said first completely-passive parallel resonant circuit having an almost infinite impedance at a third harmonic frequency of a fundamental frequency of said AC source to prevent the formation of only said third harmonic frequency and no other frequency so that there is no third harmonic frequency to remove or dissipate as heat;
- said three passive electrical branches comprise a first branch consisting of a capacitor, a second branch consisting of a reactor, and a third branch consisting of a resistor;
- and said completely-passive parallel resonant circuit being electrically connected to the neutral wire of the wye-portion of said delta-wye transformers whereby said electrical system is bi-directional in that said system is free of said third harmonic frequency both toward said nonlinear loads and back to said delta-wye transformer.
Dependencies are inferred from the claim text.