Power line communications system
AssigneeThe Autonomous Well Company, LTD.
InventorMark Patrick Robertson
Life of this patent
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Abstract
A power line communications technique (PLC) is disclosed which allows communications across any three phase electric system by modulating the impedance through earth between any two points of differing voltage on the electrical system in order to use the power supply as the communications power source thereby using the power supply current as the communications carrier. No additional coupled communications source is required and modulation of an earth link current at the power frequency is especially suitable for remote electrical loads, such as an oil well electric submersible pump, where it is most cost effective to only have the three power conductors and no neutral nor signal wires in the power cable. Embodiments of the invention are described.
Claims26
A method of communicating information along a power conductor between a power supply and a load supplied by said power supply, said method comprising the steps of causing a flow of supply current from the power supply between two different locations within the power system through a reference conductor not required for normal operation of the power system, and modulating the flow transmitted through the reference conductor by varying an impedance placed in the path of said current flow to provide at least two current states which are used to transmit information along the power system.
A power line communication system for use with a 3 phase power supply system said power line communication system comprising:
- a 3 phase power supply,
- a 3 phase load, incorporating a 3 phase power conductor to connect the 3 phase actual load to the 3 phase power supply,
- a transmitter impedance means coupled between said load and a voltage reference conductor, said transmitter impedance means being variable between at least a first impedance value and a second impedance value to generate a respective first and second current value, said first and second current values being used to transmit information along said reference conductor,
- a receiver impedance means coupled between said power supply and said voltage reference conductor, said receiver impedance means completing a transmission circuit and permitting the measurement of the current state.
Dependencies are inferred from the claim text.