Power line carrier communication system having efficient carrier signal coupling of distribution secondary lines

• US 4,008,467 A
• Filed: 09/16/1975
• Issued: 02/15/1977
• Est. Priority Date: 09/16/1975
• Status: Expired due to Term

• Current Assignee: ABB Power T&D Co Inc (ABB Limited)
• Original Assignee: Westinghouse Electric Corporation (Paramount Global (f/k/a ViacomCBS Inc.))
• Inventors: Whyte, Ian A., Pattantyus-Abraham, Tamas I.
• Primary Examiner(s): Caldwell, John W.
• Assistant Examiner(s): Groody, James J.
• Application Number:
  US05/613,835
• Time in Patent Office: 518 Days
• Field of Search: 340/310 R, 340/310 A, 340/310 CP, 307/19, 307/30, 307/11, 307/12, 307/36, 307/37, 179/170 J
• US Class Current: 307/12
• CPC Class Codes: H04B 2203/5458 Monitor sensor; Alarm systems
• CPC Class Codes: H04B 3/54 Systems for transmission via power distribution lines

Abstract

An arrangement of components for a distribution line communication system. Two or more independent secondary distribution lines are connected, through distribution transformers, to a primary distribution line. Carrier communication signals are transferred between the primary distribution line and one of the secondary distribution lines by a repeater located near one of the transformers. The carrier communication signals are propagated directly along this secondary distribution line and through associated service lines to communications terminals located near the electrical loads. Coupling apparatus is connected between the two independent secondary distribution lines to provide a path for the communication signals between the repeater and the communications terminals associated with the other secondary distribution line. The coupling apparatus provides a low-impedance path for the communication signals and a high-impedance path for signals at conventional electrical power frequencies.

Claims

1. A power line carrier communication system for communicating with first and second electric power customer locations separately served by first and second distribution transformers, respectively, of a distribution line system, said communication system comprising:

a primary distribution line transmitting carrier signals having a substantially greater frequency than the frequency of electric power also conducted therein;

means commonly connecting said first and second distribution transformers to said primary distribution line;

first and second independent secondary distribution lines each including grounded and ungrounded conductors supported adjacent the conductors of the other line at at least one location, and being connected to said first and second distribution transformers, respectively;

means for transferring said carrier signals only around said first distribution transformer;

means for connecting a first electrical load at said first customer location to said first secondary distribution line and a second electrical load at said second customer location to said second secondary distribution line;

first and second communications terminals respectively coupled to first and second secondary distribution lines near the electrical loads at said first and second customer locations, said terminals operating at the carrier signal frequency; and

means for interconnecting said first and second secondary distribution lines at the adjacently supported location, said interconnecting means providing a substantially low-attenuation path between the secondary distribution lines for signals at the carrier frequency, and providing a substantially high-attenuation path between the secondary distribution lines for signals at the power frequency thereby being effective to transfer the carrier signals between said primary distribution line and said second communication terminal while the associated second electrical load is maintained in a separately connected relationship to said second distribution transformer.

2. The system of claim 1 wherein one of the ends of each of the conductors of said first and second secondary distribution lines are adjacently supported and wherein the means for interconnecting the secondary distribution lines includes a capacitor connected in series circuit relationship between the adjacent conductor ends of the secondary distribution line conductors.

3. The system of claim 1 wherein the means for interconnecting the secondary distribution lines includes a capacitor connected between a non-grounded conductor of one secondary distribution line and a non-grounded conductor of the other secondary distribution line.

4. The system of claim 1 wherein the means for interconnecting the secondary distribution lines includes first and second windings which are inductively coupled to each other, said first winding being capacitively coupled to the first secondary distribution line, and the second winding being capacitively coupled to the second secondary distribution line.

5. The system of claim 1 wherein the means for interconnecting the secondary distribution lines includes a first coupling transformer having primary and secondary windings, a second coupling transformer having primary and secondary windings, and first and second capacitors, with the secondary windings of the first and second coupling transformers connected together, the primary windings of the first coupling transformer and the first capacitor serially connected between ground and one of the non-grounded conductors of the first secondary distribution line, and the primary winding of the second coupling transformer and the second capacitor serially connected between ground and one of the non-grounded conductors of the second secondary distribution line.

6. A power line carrier communication system comprising:

a primary distribution line transmitting carrier frequency signals;

first and second distribution transformers connected to said primary distribution line;

first and second independent secondary distribution lines having an adjacent support location and being respectively connected between said first and second distribution transformers and first and second customer locations;

a first electrical load connected to the first secondary distribution line at said first customer location and a second electrical load connected to the second secondary distribution line at said second customer location;

first and second communications terminals respectively coupled to the first and second secondary distribution lines at said first and second customer locations near the associated electrical loads, said terminals operating at the carrier frequencies which are substantially greater than the frequency of the electrical power on the distribution lines;

a repeater connected around said first distribution transformer and between the primary distribution line and the first secondary distribution line, said repeater providing an efficient path at the carrier signal frequencies for two-way communications between the primary and first secondary distribution lines; and

means for interconnecting said first and second secondary distribution lines, said interconnecting means providing a substantially low-attenuation path between the secondary distribution lines for signals at the carrier frequency, and providing a substantially high-attenuation path between the secondary distribution lines for signals at the power frequency so that said second communications terminal is coupled at the carrier frequencies to said primary distribution line via said repeater and said first distribution transformer while said second electrical load remains independently connected to said second distribution transformer at the electrical power frequency.