Remote monitoring system transmitter

• US 4,535,447 A
• Filed: 01/31/1983
• Issued: 08/13/1985
• Est. Priority Date: 01/31/1983
• Status: Expired due to Term

• Current Assignee: Hazeltine Corporation (BAE Systems Plc)
• Original Assignee: Hazeltine Corporation (BAE Systems Plc)
• Inventors: Haley, Timothy P., Rosanes, Albert P.
• Primary Examiner(s): Olms, Douglas W.
• Assistant Examiner(s): Scutch, III, Frank M.
• Application Number:
  US06/462,301
• Time in Patent Office: 925 Days
• Field of Search: 370/77, 370/124, 370/70, 370/69.1, 370/121, 179/2.51, 340/310 R
• US Class Current: 370/537
• CPC Class Codes: H02J 13/00009 using pulsed signals
• CPC Class Codes: H04B 2203/5408 using protocols
• CPC Class Codes: H04B 2203/5416 by adding signals to the wave form of the power source
• CPC Class Codes: H04B 2203/542 using zero crossing information
• CPC Class Codes: H04B 2203/5458 Monitor sensor; Alarm systems
• CPC Class Codes: H04B 3/542 the information being in digital form
• 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

A solid state remote monitoring transmitter which transmits a 40 bit word that contains status information about a transformer via the secondary of a power distribution network to a central receiver associated with the primary (feeder) cable supplying the transformer. A program card specifies the carrier signal frequency and the identification of the transmitter. Multiple ananlog inputs are switched through a multiplexer to an A/D converter, the output of which is stored in a shift register to form the 40-bit word. The word is DPSK - coded by clock pulses in synchronism to the 60 Hz zero crossings of the AC power source and amplified by an unregulated power supply which is also powered by the AC power source. The phase transitions of the DPSK - coded word occur at the zero crossings diminishing any transients in the transmitter circuitry which would be caused by the phase transitions.

Claims

1. An apparatus for transmitting information over the secondary network of a power distribution network including a power source, a primary source, a primary network, a transformer and a secondary network comprising:

(a) a multiplexer having multiple inputs and an output;

(b) first means for providing to the inputs of the multiplexer analog information corresponding to the information to be transmitted;

(c) second means having an input connected to the output of the multiplexer for converting analog information provided by the multiplexer output into digital information and supplying the digital information at an output;

(d) a shift register for storing the digital information having an input connected to the output of the second means and having an output supplying the digital information stored in the shift register;

(e) third means for modulating a carrier signal with the digital information stored in the shift register;

(f) fourth means for transmitting over the power distribution network the modulated carrier signal supplied by the third means; and

(g) timing means associated with the secondary network of a power distribution network and including a zero crossing detector for supplying a clock signal and for synchronizing said timing means to the power source, said timing means being responsive to the clock signal and controlling the multiplexer switching and the third means.

2. The apparatus of claim 1 wherein said multiplexer has three analog inputs and a single output connected to said second means.

3. The apparatus of claim 2 wherein said second means is an analog-to-digital converter having a conversion mode and a reset mode.

4. The apparatus of claim 3 wherein the analog information provided by the first means comprises load current information relating to the transformer.

5. The apparatus of claim 4 wherein the information is digital information in a series of digital words;

wherein the third means modulates a carrier signal with the digital information; and

wherein the fourth means transmits the modulated carrier signal such that the digital words are each transmitted between zero crossings.