Apparatus and methods for power network coupling

• US 5,694,108 A
• Filed: 05/01/1996
• Issued: 12/02/1997
• Est. Priority Date: 05/01/1996
• Status: Expired due to Term

• Current Assignee: ABB Power T&D Limited (ABB Limited)
• Original Assignee: ABB Power T&D Limited (ABB Limited)
• Inventors: Shuey, Kenneth C.
• Primary Examiner(s): Mullen, Thomas
• Assistant Examiner(s): Wu, Daniel J.
• Application Number:
  US08/637,935
• Time in Patent Office: 580 Days
• Field of Search: 340/310.01, 340/310.05, 340/310.06, 340/310.07
• US Class Current: 340/538.16
• CPC Class Codes: H04B 2203/5408 using protocols
• CPC Class Codes: H04B 2203/5425 improving S/N by matching impedance, noise reduction, gain control
• CPC Class Codes: H04B 2203/5445 Local network
• CPC Class Codes: H04B 2203/5458 Monitor sensor; Alarm systems
• CPC Class Codes: H04B 2203/5483 using coupling circuits
• CPC Class Codes: H04B 2203/5491 using filtering and bypassing
• CPC Class Codes: H04B 3/56 Circuits for coupling, blocking, or by-passing of signals

Abstract

Methods and apparatus for establishing communications between electrical and electronic devices utilizing existing power signal distribution networks are disclosed. In such methods and apparatus the transmitting and receiving components of such devices are coupled between line and ground. Such coupling is achieved utilizing a coupler, a first frequency reactive device, such as a drain coil or inductor, connected in series with neutral and a second frequency reactive device, such as a capacitor connected between neutral ground. For use with existing electronic equipment, an adaptor for coupling the communications signal to a power signal distribution network is also disclosed.

Claims

1. Apparatus for coupling a communications signal to a power signal distribution network, said network comprising line, ground and neutral paths, said apparatus comprising, a coupler for coupling said communication signal between said line and ground paths and a first frequency reactive device, connected in series with said neutral path, wherein the impedance of said first frequency reactive device increases as the frequency of a signal applied to said frequency reactive device increases.

2. The apparatus of claim 1, wherein said first frequency reactive device comprises a drain coil, connected in series with said neutral path.

3. The apparatus of claim 1, wherein said first frequency reactive device comprises an inductor, connected in series with said neutral path.

4. The apparatus of claim 1, further comprising a second frequency reactive device, connected between said neutral path and said ground path, wherein the impedance of said second frequency reactive device decreases as the frequency of a signal applied to said second frequency reactive device increases.

5. The apparatus of claim 4, wherein said second frequency reactive device comprises a capacitor.

6. An adaptor for coupling a communications signal to a power signal distribution network, said network comprising line, ground and neutral paths, said adaptor comprising, a first frequency reactive device, connected in series with said neutral path, wherein the impedance of said first frequency reactive device increases as the frequency of a signal applied to said first frequency reactive device increases and a second frequency reactive device, connected between said neutral path and said ground path, wherein the impedance of said second frequency reactive device decreases as the frequency of a signal applied to said second frequency reactive device increases.

7. The adaptor of claim 6, wherein said first frequency reactive device comprises an inductor, connected in series with said neutral path.

8. The adaptor of claim 6, wherein said second frequency reactive device comprises a capacitor.

9. The adaptor of claim 6, further comprising a Zener diode pair connected in parallel with said first frequency reactive device.

10. Apparatus for coupling a communications signal to a power signal distribution network, said network comprising line, ground and neutral paths, said apparatus comprising, a coupler for coupling said communication signal between said line and ground paths;

a first filter, connected to said neutral path, wherein said first filter is adapted to allow said power signal to pass therethrough; and

a second filter, connected to said ground path, wherein said second filter is adapted to allow said communications signal to pass therethrough.

11. The apparatus of claim 10, wherein said first filter comprises an inductor, connected in series with said neutral path.

12. The apparatus of claim 10, wherein said second filter comprises a capacitor.

13. A method for coupling a communications signal to a power signal distribution network, said network comprising line ground and neutral paths, said method comprising the steps of:

transmitting said communication signal on said line and ground paths and blocking the transmission of said communication signal on said neutral path;

said step of transmitting comprising the step of connecting a coupler, for coupling said communication signal, between said line and ground paths and connecting a first frequency reactive device to said neutral path, wherein the impedance of said first frequency reactive device increases as the frequency of a signal applied to said first frequency reactive device increases.

14. The method of claim 13, wherein said step of connecting a first frequency reactive device comprises the step of connecting an inductor in series with said neutral path.

15. The method of claim 13, further comprising the step of connecting a second frequency reactive device between said neutral path and said ground path, wherein the impedance of said second frequency reactive device decreases as the frequency of a signal applied to said second frequency reactive device increases.

16. The method of claim 15, wherein said step of connecting a second frequency reactive device comprises the step of connecting a capacitor between said neutral path and said ground path.