Sensing current flowing through a power line

1. A method comprising:

transducing a power frequency current flowing through a power line, into a power frequency voltage, via an inductive coupler that couples a communications signal from said power line;

separating said power frequency voltage from said communications signal;

determining a value of a parameter of said power frequency current from said power frequency voltage;

modulating said value onto a resultant communication signal; and

coupling said resultant communication signal to said power line, via said inductive coupler.

2. The method of claim 1 , wherein said inductive coupler includes:

(a) a magnetic core having an aperture therethrough, wherein said power line is routed through said aperture and serves as a primary winding for said inductive coupler; and

(b) a secondary winding wound around a portion of said magnetic core, wherein said power frequency voltage is induced across said secondary winding.

3. The method of claim 1 , wherein said separating comprises passing said power frequency voltage through a filter that blocks said communications signal.

4. The method of claim 3 ,

wherein said communications signal is routed to a circuit that passes said communications signal and blocks said power frequency voltage, and

wherein said method further comprises:

routing said power frequency voltage around said circuit;

multiplexing said power frequency voltage and said communications signal together, downstream of said circuit, to yield a multiplexed signal; and

demultiplexing said multiplexed signal, prior to said determining.

5. The method of claim 1 , wherein said power frequency voltage has a frequency in a range of about 50-60 Hz, and said communications signal has a frequency of greater than about 1 MHz.

6. The method of claim 1 , wherein said parameter is selected from the group consisting of (a) a magnitude of said power frequency current, and (b) a phase of said power frequency current, with respect to a reference phase.

7. The method of claim 1 ,

wherein said inductive coupler includes

(a) a magnetic core having an aperture therethrough, wherein said power line is routed through said aperture and serves as a primary winding for said inductive coupler; and

(b) a secondary winding wound around a portion of said magnetic core, wherein said coupled signal is induced across said secondary winding, and

wherein said separating comprises passing said power frequency voltage through a filter that blocks said communications signal.

8. A system comprising:

an inductive coupler that (a) couples a communications signal from a power line, and (b) transduces a power frequency current flowing through said power line, into a power frequency voltage;

a filter that separates said power frequency voltage from said communications signal;

a processor that determines a value of a parameter of said power frequency current from said power frequency voltage; and

a modulator that modulates said value onto a resultant communications signal,

wherein said system couples said resultant communications signal to said power line, via said inductive coupler.

9. The system of claim 8 ,

wherein said inductive coupler includes:

(a) a magnetic core having an aperture therethrough, wherein said power line is routed through said aperture and serves as a primary winding for said inductive coupler; and

(b) a secondary winding wound around a portion of said magnetic core, wherein said value of a parameter of said power frequency current from said power frequency voltage is induced across said secondary winding.

10. The system of claim 8 , wherein said filter passes said power frequency voltage and blocks said communications signal.

11. The system of claim 10 ,

wherein said communications signal is routed to a circuit that passes said communications signal and blocks said power frequency voltage, and

wherein said system further comprises:

a bypass module that routes said power frequency voltage around said circuit;

an arrangement that multiplexes said power frequency voltage and said communications signal together, downstream of said circuit, to yield a multiplexed signal; and

an arrangement that demultiplexes said multiplexed signal so that said processor can determine said value.

12. The system of claim 8 , wherein said power frequency voltage has a frequency in a range of about 50-60 Hz, and said communications signal has a frequency of greater than about 1 MHz.

13. The system of claim 8 , wherein said parameter is selected from the group consisting of (a) a magnitude of said power frequency current, and (b) a phase of said power frequency current, with respect to a reference phase.

14. The system of claim 8 ,

wherein said inductive coupler includes

(a) a magnetic core having an aperture therethrough, wherein said power line is routed through said aperture and serves as a primary winding for said inductive coupler; and

(b) a secondary winding wound around a portion of said magnetic core, wherein said coupled signal is induced across said secondary winding, and

wherein said filter passes said power frequency voltage and blocks said communications signal.