IMPROVED COUPLING ARRANGEMENT FOR POWER LINE CARRIER SYSTEMS

• US 3,846,638 A
• Filed: 09/06/1973
• Issued: 11/05/1974
• Est. Priority Date: 10/02/1972
• Status: Expired due to Term

• Current Assignee: Daniel L. Wetherell
• Original Assignee: Daniel L. Wetherell
• Inventors: Wetherell, Daniel L.
• Primary Examiner(s): Pellinen, A. D.
• Application Number:
  US05/394,559
• Time in Patent Office: 425 Days
• Field of Search: 307/1,3 340/31R
• US Class Current: 307/3
• CPC Class Codes: H04B 2203/5425 improving S/N by matching impedance, noise reduction, gain control
• CPC Class Codes: H04B 2203/5466 using three phases conductors
• 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

A power line carrier system is coupled to two or more phase wires of an electrical power transmission line by transformers and coaxial transmission lines. Each phase wire to be used is provided with a coupling capacitor which is respectively coupled to one end of a coaxial line through an impedance matching transformer. The other ends of the coaxial lines are coupled to the carrier system through one or more isolation transformers. Use of this coupling arrangement eliminates the previously used, exposed unbalanced lines, and their inherent disadvantages. Where a plurality of phase wires are used, this arrangement permits the carrier to be coupled to the phase wires with various relative voltage magnitudes and various relative phases.

Claims

1. In a power line carrier system, an improved arrangement for coupling the carrier system to at least two phase wires of an electrical power transmission line, said improved arrangement comprising:

a. first and second impedance matching transformers each having coupled primary and secondary windings;

b. means for coupling said primary winding of said first impedance matching transformer to a first phase wire of said electrical power transmission line;

c. means for coupling said primary winding of said second impedance matching transformer to a second phase wire of said electrical power transmission line;

d. an isolation transformer having coupled primary and secondary windings, said primary winding having a center tap between its ends;

e. means, including at least one coaxial line, for respectively cOnnecting one end of each of said secondary windings of said impedance matching transformers to one of said ends of said primary winding of said isolation transformer;

f. a common impedance having one end connected to said center tap of said isolation transformer primary winding and the other end connected to the other ends of said secondary windings of said impedance matching transformers;

g. and a coaxial line connected to said secondary winding of said isolation transformer for connection to a carrier system.

2. The improved arrangement of claim 1 wherein said means for connecting said secondary windings of said impedance matching transformers to said primary winding of said isolation transformer comprises two coaxial lines.

3. The improved arrangement of claim 1 wherein said means for connecting said secondary windings of said impedance matching transformers to said primary winding of said isolation transformer comprises said one coaxial line and a single unbalanced line.

4. In a power line carrier system, an improved arrangement for coupling the carrier system to at least two phase wires of an electrical power transmission line, said improved arrangement comprising:

a. first and second impedance matching transformers each having a primary winding and a secondary winding coupled thereto;

b. means for coupling said primary winding of said first impedance matching transformer to a first of said phase wires of said electrical power transmission line;

c. means for coupling said primary winding of said second impedance matching transformer to a second of said phase wires of said electrical power transmission line;

d. a first isolation transformer having a primary winding with a center tap and a secondary winding coupled thereto;

e. first and second coaxial lines each having inner and outer conductors;

f. means for connecting said inner conductor of said first coaxial line between one end of said primary winding of said first isolation transformer and one end of said secondary winding of said first impedance matching transformer;

g. means for connecting said inner conductor of said second coaxial line between the other end of said primary winding of said first isolation transformer and one end of said secondary winding of said second impedance matching transformer;

h. a resistor having a magnitude substantially half the impedance of said coaxial lines;

i. means connecting one end of said resistor to said center tap of said isolation transformer and the other end of said resistor to said outer conductors of said coaxial lines;

j. means connecting said outer conductor of said first coaxial line to the other end of said secondary winding of said first impedance matching transformer;

k. means connecting said outer conductor of said second coaxial line to the other end of said secondary winding of said second impedance matching transformer;

l. and means connected to said secondary winding of said first isolation transformer for connection to a carrier system.

5. The improved arrangement of claim 4 wherein said outer conductors of said first and second coaxial lines are grounded.

6. In a power line carrier system, an improved arrangement for coupling the carrier system to at least three phase wires of an electrical power transmission line, said improved arrangement comprising:

a. first, second and third impedance matching transformers each having a primary winding and a secondary winding coupled thereto;

b. means for coupling said primary winding of said first impedance matching transformer to a first of said phase wires of said electrical power transmission line;

c. means for coupling said primary winding of said second impedance matching transformer to a second of said phase wires of said electrical power transmission line;

d. means for coupling said primary winding of said third impedance matching transformer to a third of said phase wires of said electrical power transmission line;

e. first and second isolation transformers each having a primary winding and a secondary winding coupled thereto;

f. means including first and third coaxial lines for respectively connecting said secondary windings of said first and third impedance matching transformers to said primary winding of said first isolation transformer;

g. means including a second coaxial transmission line for coupling said secondary winding of said second impedance matching transformer to said primary winding of said second isolation transformer;

h. means for coupling said secondary winding of said first isolation transformer to said primary winding of said second isolation transformer;

i. and means connected to said secondary winding of said second isolation transformer for connection to a carrier system.

7. In a power line carrier system, an improved arrangement for coupling the carrier system to at least four phase wires of an electrical power transmission line, said imporved arrangement comprising:

a. first, second, third, and fourth impedance matching transformers each having a primary winding and a secondary winding coupled thereto;

b. said primary windings of said impedance matching transformers being adapted to be coupled to a respective one of said four phase wires of said electrical power transmission line;

c. first and third isolation transformers each having a primary winding with a center tap and a secondary winding coupled thereto;

d. means including the inner conductor of a coaxial line for respectively coupling one end of said secondary windings of said first and second impedance matching transformers to the ends of said primary winding of said first isolation transformer;

e. means including the inner conductor of a coaxial line for respectively coupling one end of said secondary windings of said third and fourth impedance matching transformers to the ends of said primary winding of said third isolation transformer;

f. means coupling the other ends of said secondary windings of said impedance matching transformers to the outer conductors of said coaxial lines;

g. a second isolation transformer having a primary winding with a center tap and a secondary winding coupled thereto;

h. means including the inner conductor of a coaxial line for respectively coupling one end of said secondary windings of said first and third isolation transformers to the ends of said primary winding of said second isolation transformer;

i. means coupling the other ends of said secondary windings of said first and third isolation transformer to said outer conductors of said coaxial lines;

j. first, second, and third resistors each having a magnitude substantially equal to half the impedance of said coaxial lines respectively coupled between said center taps of said primary windings of said first, second, and third isolation transformers and said outer conductors of said coaxial lines;

k. and means coupled to said secondary winding of said second isolation transformer for connection to a carrier system.

8. In a power line carrier system, an improved arrangement for coupling the carrier system to at least six phase wires of an electrical power transmission line, said improved arrangement comprising:

a. first, second, third, fourth, fifth, and sixth impedance matching transformers each havin a a primary winding and a second winding coupled thereto;

b. said primary windings of said impedance matching transformers being adapted to be coupled to a respective one of said six phase wires of said electrical power transmission line;

c. first, second, third, fourth, and fifth isolation transformers each having a primary winding with a center tap and a secondary winding coupled thereto;

d. means including the inner conductor of a coaxial line for respectively coupling one end of said secondary windings of said first and second impedance matching transformers to the ends of said primary winding of said first isOlation transformer;

e. means including the inner conductor of a coaxial line for respectively coupling one of said secondary windings of said fourth and fifth impedance matching transformers to the ends of said primary winding of said fourth isolation transformer;

f. means including the inner conductor of a coaxial line for respectively coupling one end of said secondary winding of said first isolation transformer and one end of said secondary winding of said third impedance matching transformer to the ends of said primary winding of said second isolation transformer;

g. means including the inner conductor of a coaxial line for respectively coupling one end of said secondary winding of said fourth isolation transformer and one end of said secondary winding of said sixth impedance matching transformer to the ends of said primary winding of said fifth isolation transformer;

h. means including the inner conductor of a coaxial line for respectively coupling one end of said secondary windings of said second and fifth isolation transformers to the ends of said primary winding of said third isolation transformer;

i. means for connecting the other ends of said secondary windings of said first through sixth impedance matching transformers and the other ends of said secondary windings of said first, second, fourth, and fifth impedance matching transformers to the outer conductors of said coaxial lines;

j. first, second, third, fourth, and fifth resistors each having a magnitude substantially equal to half the impedance of said coaxial lines respectively coupled between said center taps of said primary windings of said first, second, third, fourth, and fifth isolation transformers and said outer conductors of said coaxial lines;

k. and means coupled to said secondary winding of said third isolation transformer for connection to a carrier system.