COMMUNICATIONS SYSTEM FOR ELECTRIC POWER UTILITY

• US 3,702,460 A
• Filed: 11/30/1971
• Issued: 11/07/1972
• Est. Priority Date: 11/30/1971
• Status: Expired due to Term

• Current Assignee: John B. Blose
• Original Assignee: John B. Blose
• Inventors: Blose, John B.
• Primary Examiner(s): Yusko, Donald J.
• Application Number:
  US05/203,348
• Time in Patent Office: 343 Days
• Field of Search: 340/310,150,151,152 307/3
• US Class Current: 340/3.1
• CPC Class Codes: H02J 13/00007 using the power network as support for the transmission
• CPC Class Codes: H02J 13/00034 the elements or equipment being or involving an electric power substation
• CPC Class Codes: H04B 2203/5416 by adding signals to the wave form of the power source
• CPC Class Codes: H04B 2203/5425 improving S/N by matching impedance, noise reduction, gain control
• CPC Class Codes: H04B 2203/5433 Remote metering
• CPC Class Codes: H04B 2203/5441 Wireless systems or telephone
• CPC Class Codes: H04B 2203/5458 Monitor sensor; Alarm systems
• 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 3/542 the information being in digital form
• CPC Class Codes: H04Q 9/14 Calling by using pulses
• CPC Class Codes: Y02E 60/00 Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
• CPC Class Codes: Y04S 40/121 using the power network as support for the transmission

Abstract

An electric power utility communication system is disclosed comprising a plurality of geographically distributed group control units and groups of terminal processor units, with each such terminal processor unit within a group coupled to a respective group control unit through the neutral conductor of the power utility distribution lines. Availability of the neutral as a communications link is achieved by inserting a parallel resonant circuit between the neutral and ground at each ground point in the system. Alternately, the signal generating and/or receiving equipment may be connected between the conventionally grounded neutral and deep earth ground, to develop the communications signal across the earth impedance. Communications information is transmitted over the neutral by coded high frequency signals to the terminal processor units which have electronic logic capacity to accept and perform command functions, interrogate meters, and transmit information back over the neutral to their respective group control units. Overall control is achieved by a central computer controller coupled to each group control unit by conventional transmission means, and which generates and receives coded signals through the group control units.

Claims

1. A computer-controlled communication system for an electric power utility for communicating with terminal points of its energy transmission network by means of high frequency coded signals, comprising:

a. a plurality of group signal transceivers, each in communications linkage with said computer, for receiving coded data signals from said computer and channeling them to said terminal points at said high frequency, and for Transmitting system data to said computer;

b. signal processing means having a terminal signal processing unit located at each of said terminal points, for receiving and processing said high frequency coded signals, and for generating system data;

c. a signal transmission network for transmitting said coded signals from said transceivers to said signal processing means comprising the neutral of said power utility transmission network and ground return;

d. terminal coupling means for coupling said signal processing means to said neutral;

e. transceiver coupling means for coupling each of said group signal transceivers to said neutral and for limiting to a respective group transceiver communication of such coded signals with a specific group of said terminal signal processing units;

f. each such terminal signal processing unit comprising;

i. data receiving means for detecting and storing said high frequency coded signals;

ii. data processing means, coupled to said data receiving means, for processing said received coded signals to generate an electrical signal in accordance with the information content thereof;

iii. function driver means, coupled to said data processing means, for generating electrical signals to perform functions specified by said coded signals;

iv. data device reading means, coupled to said data processing means, for interrogating and deriving coded information from data devices coupled to the respective terminal processor, in accordance with the information content of said received coded signals; and

, v. data transmitting means, coupled to said data device reading means, and cooperating with that group transceiver with which said respective terminal signal processing unit is in communications linkage for transmitting such derived data thereto; and

g. wherein said data receiving means comprises;

i. amplifier receifier means for demodulating said high frequency coded signals and generating pulses representing data bits;

ii. a shift register, having a plurality of bit positions, coupled to said amplifier rectifier means;

iii. a clock generator, coupled to and cooperating with said shift register, for loading said pulses into said shift register;

iv. shift inhibit means, for inhibiting loading of further pulses into said shift register after it has been fully loaded; and

, v. time delay-reset means, for resetting said shift register after a predetermined time delay.

2. The system as described in claim 1, wherein said shift register is of the serial-input parallel-output type and said data processing means includes an address comparator comprising two multiple input logic circuits having their inputs coupled to respective outputs of said shift register, each of said logic circuits providing a signal output when all input signals thereto are of the same sense, and a third logic circuit, the output signals of said two logic circuits being applied to respective inputs of said third logic circuit, said third logic circuit providing an output signal when all signal inputs are of the same sense.

3. The system as described in claim 2 wherein said shift register is of the serial-input parallel-output type and said data processing means comprises a first AND circuit having a plurality of inputs coupled to respective output positions of said shift register, a negative AND circuit having a plurality of inputs coupled to other respective output positions of said shift register, the respective couplings of said shift register output positions with respective input positions of said first AND circuit and said negative AND circuit constituting a fixed address, an inverter coupled to the output of said negative AND circuit, and a second AND circuit having input terminals coupled to the outputs of said AND circuit and said inverter, whereby the binary information in some of said shift register positions is compared with the fixed address information represented by the connecTions of said AND circuit and said negative AND circuit, such that an output signal of said second AND circuit is produced only when such binary information in said some of said shift register positions corresponds to said fixed address information.

4. The system as described in claim 3 wherein said second AND circuit is a three-input circuit, having a third input connected to the first position of said shift register.

5. The system as described in claim 4 wherein said function driver means comprises a mass AND circuit having one input coupled to said first position of said shift register and another input coupled to another output position of said shift register.

6. The system as described in claim 5, wherein said function driver means comprises an addressable AND circuit having one input coupled to the output of said second AND circuit and another input coupled to an output position of said shift register.

7. The system as described in claim 6, wherein said function driver means comprises an addressable AND circuit having one input coupled to the output of said second AND circuit and another input coupled to an output position of said shift register, and a mass AND circuit having one input coupled to said first position of said shift register and another input coupled to another output position of said shift register.

8. The system as described in claim 7, wherein said data device reading means comprises a parallel-input serial-output shift register, coupling means for coupling into said shift register the data in an encoded data device, and a clock generator for shifting out the data in said shift register.

9. The system as described in claim 8, wherein said data transmitting means comprises a Schmitt Trigger, a pair of silicon controlled rectifiers in antiparallel configuration and coupled to a relatively low frequency source, the gates thereof being driven by the output of said Schmitt Trigger, and a carrier modulate relay coupled to and driven by said silicon controlled rectifiers, said carrier modulate relay being in parallel with the associated terminal resonant circuit, whereby the high frequency impedance across said resonance circuit is time-modulated at twice said relatively low frequency.

10. The system as described in claim 9, wherein each group processor includes a high frequency current generator coupled to said neutral for generating a continuous high-frequency current which is transmitted over said neutral, said current generator cooperating with said carrier modulate relay to produce a pulse coded high frequency current, and differential amplifier apparatus in said group processor for detection of said high frequency pulse modulated current.

11. In an electric power utility having a power transmission network with a continuous neutral wire connected to system ground at multiple points, such system ground being electrically separate from earth ground by a finite impedance, and said power transmission network having at least one phase wire, apparatus comprising:

a. high frequency signal generator means for generating high frequency coded signals, and having a pair of output terminals;

b. first coupling means at a first point on said network for coupling said high frequency coded signals between said neutral and earth ground, a first of said output terminals being at system ground and the second of said output terminals being at earth ground;

c. a closed path transmission network comprising said neutral and earth ground return, for transmission of said high frequency signals between said first point and said multiple system ground points;

d. signal processing means having a terminal signal processing unit located at each of said multiple points for receiving and processing said high frequency coded signals, and for generating system data, each said unit having one electrical terminal at system ground and another electrical terminal at earth ground; and

e. whereby said coded siGnals generated at said first point are developed across said finite impedance between system ground and earth ground at such first point, and said coded signals received at each of said multiple points are developed across said finite impedance between each such system ground point and earth ground.

12. The system as described in claim 11 wherein said second output terminal is connected through a metallic ground rod to earth ground, and said another electrical terminal of each terminal processing unit is connected to earth ground through a metallic ground rod.

13. An electric power utility communication system for transmission of coded signals to and from points a neutral on an electric energy transfer network, such network including aneutral conductor and operating at power frequency, comprising:

a. signal generating means for generating coded high frequency electric signals at a first point on said network;

b. a signal transmission network for transmitting said coded high frequency signals from said first point to at least one other point on said network, said signal transmission network comprising a closed loop in which are included a first path consisting of said neutral conductor connected between said first point and said other point, and a second path consisting of ground return between said two points;

c. neutral coupling means, coupling said neutral to system ground at a plurality of points on the network, said system ground being electrically separate from earth ground by a finite impedance, said plurality containing at least said first point;

d. first coupling means coupling said signal generating means between system ground and earth ground;

e. signal processing means at said other point for processing said coded high frequency signals;

f. second coupling means, coupling said signal processing means to said neutral at said other point;

g. said coded signals being transmitted over a closed path defined by said neutral, ground, first coupling means and second coupling means; and

h. wherein said neutral is connected to system ground at said one other point, and said second coupling means comprises a metallic ground rod in connection with earth ground, whereby the processing means is connected between said system ground and earth ground.

14. The system as described in claim 13, wherein said signals are transmitted from said first point to respective signal processing means at a plurality of other points on said network, each such signal processing means being coupled to said neutral conductor and to system ground at a respective other point, and comprising:

a. data receiving means for receiving said coded signals;

b. address comparator means for determining when said each signal processing means has been addressed;

c. data reading means, controlled by said address comparator means, for reading encoded data; and

d. return data transmitting means for generating coded return signals representing said encoded data.

15. The system as described in claim 3, wherein said transmission network extends over a portion of said electric energy transfer network having at least one transformer, the neutral conductors one each side of said transformer being connected to provide a continuous neutral transmission path.

16. The system as described in claim 15, wherein a blocking parallel resonant circuit is connected in series with said neutral conductor at a point beyond which transmission of said coded signals is desired to be inhibited, said blocking circuit having a substantial impedance at said high frequency and a negligible impedance at the power frequency, thereby blocking transmission of coded signals from said signal generating means beyond the point of connection of said blocking circuit while permitting substantially uninhibited transmission of power frequency current therethrough.

17. The system as described in claim 16, having a plurality of blocking circuits functionally identical with said bloCking circuit, said blocking circuits being located such as to confine the transmission of said signals to specific portions of said neutral conductor, thereby delimiting a group of said signal processing means which are in high frequency communication with said signal generating means.

18. The system as described in claim 17 in which each of said signal generating means additionally has circuitry for receiving high frequency electric signal information and generating coded high frequency signals in accordance therewith, said system also including a computer having capacity for generating and transmitting said high frequency electric signal information to the plurality of signal generating means, and communication coupling means coupling said computer to each of said signal generating means for high frequency electric communication therewith.