# US 9,883,259 B2 · Synchronized metrology in power generation and distribution networks > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,883,259 B2 - Document ID: US9883259B2 - Status: Granted - Kind: B2 - Application number: 14/987,134 - Filed: 2016-01-04 - Published: 2016-07-07 - Granted: 2018-01-30 - Earliest claimed: 2011-08-15 - Assignees: Digimarc Corporation - Applicants: Digimarc Corporation - Inventors: Geoffrey B. Rhoads; Conrad Eustis; Tyler J. McKinley - Web page: https://patentgrep.com/patent/US9883259B2 ## CPC - H04Q 9/00: Arrangements in telecontrol or telemetry systems for selectively calling a substation from a main station, in which substation desired apparatus is selected for applying a control signal thereto or for obtaining measured values therefrom - G01R 19/175: Indicating the instants of passage of current or voltage through a given value, e.g. passage through zero - G01R 19/2513: {Arrangements for monitoring electric power systems, e.g. power lines or loads; Logging} - G01R 29/18: Indicating phase sequence; Indicating synchronism - G06Q 50/06: Energy or water supply - G08C 19/12: in which the signal transmitted is frequency or phase of AC - H04Q 9/04: Arrangements for synchronous operation - G01D 4/002: {Remote reading of utility meters} - G01D 2204/45: Utility meters networked together within a single building - G01D 2204/47: Methods for determining the topology or arrangement of meters in a network - G01R 22/10: using digital techniques - H04Q 2209/60: for transmitting utility meters data, i.e. transmission of data from the reader of the utility meter - Y02B 90/20: Smart grids as enabling technology in buildings sector (smart grids supporting the management or operation of end-user stationary applications in general, or like technologies with no associated climate change mitigation effect Y04S20/00) - Y02E 40/70: Smart grids as climate change mitigation technology in the energy generation sector - Y02E 60/00: Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation - Y04S 10/00: Systems supporting electrical power generation, transmission or distribution - Y04S 10/22: Flexible AC transmission systems [FACTS] or power factor or reactive power compensating or correcting units - Y04S 20/30: Smart metering, e.g. specially adapted for remote reading - H04Q: SELECTING (switches, relays, selectors H01H; wireless communication networks H04W) - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) - G06Q: INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES; SYSTEMS OR METHODS SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES, NOT OTHERWISE PROVIDED FOR - G08C: TRANSMISSION SYSTEMS FOR MEASURED VALUES, CONTROL OR SIMILAR SIGNALS (fluid pressure transmitting systems F15B; mechanical means for transferring the output of a sensing member into a different variable G01D5/00; mechanical control systems G05G) - G01D: MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR - Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION - Y04S: SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS ## Abstract Phasor Measurement Units (PMUs) tend to be specialized and expensive—relegated to only key points in power distribution networks, and are generally reliant on GPS technology. The present disclosure details how any smart meter—using wireless communication—can perform sub-microsecond-grade synchrophasor measurements. Other aspects concern smart meter-based determination of A, B or C phase of the tri-phase power network. This can involve count-stamp enabling message packets sent to and/or from a smart meter, and then associating such count-stamps to local measurements of power phase by a metrology unit. Once a network of such enabled smart meters and other devices is formed, sub-microsecond metropolitan-wide and entire region-wide synchronizing time standard can calibrate local measurements of power phase, where simple A, B and C phase determination is one low hanging fruit application of such. Low cost aggregate monitoring of metropolitan-wide synchrophasors promises a next chapter of importance for that relatively recent art. ## Claims ### Claim 1 A method useful in determining an electric power phase relationship between two devices, a first device comprising a power meter device connected to a power distribution system and a second device comprising another device connected to the power distribution system, the method characterized by processing one or more messages received from the second device, together with zero crossing data generated by the first device, to determine relative timing between zero crossings of power signals sensed at said devices, wherein the message received from the second device is clock-stamped by the first device. ### Claim 2 (depends on 1) The method of claim 1 that further includes, from said relative timing, determining whether the power signal at the first device is (a) in phase with the power signal at the second device; (b) leads the power signal at the second device by 120 degrees; or (c) lags the power signal at the second device by 120 degrees. ### Claim 3 (depends on 1) The method of claim 1 in which both of said devices comprise power meter devices. ### Claim 4 (depends on 1) The method of claim 1 that includes count-stamping the message(s) received from the second device, by reference to clock counts from a free-running clock in the first device that runs at 100 KHz or more. ### Claim 5 (depends on 1) The method of claim 1 that includes determining relative timing between the zero crossing measurements to an accuracy of better than 25 microseconds. ### Claim 6 (depends on 1) The method of claim 1 wherein at least one of said devices is devoid of a GPS receiver. ### Claim 7 (depends on 1) The method of claim 1 wherein the message received from the second device is clock-stamped. ### Claim 8 (depends on 7) The method of claim 7 in which the message received from the second device is clock-stamped by the second device. ### Claim 9 (depends on 7) The method of claim 7 in which the message received from the second device is clock-stamped by the second device to indicate a zero-crossing event at the second device. ### Claim 10 A method of determining phase relationship among power meters, the method comprising the acts: collecting count stamped messages transmitted between nodes in a network including at least first and second power meters, the messages including zero crossing measurements of a power signal sensed at a corresponding power meter; from the count stamped messages, determining relative timing among clocks within the power meters; and from the relative timing and zero crossing measurements, determining relative phases between the power meters; wherein the power meters include a first clock for zero crossing measurements and a second clock for count-stamping a message communicated with another node in the network, and the method further includes determining relative timing between said first and second clocks. ### Claim 11 (depends on 10) The method of claim 10 wherein the zero crossing measurements within the first power meter and the count-stamping of a message by the first power meter are made relative to a common clock within the first power meter. ### Claim 12 A power meter comprising: a metrology unit for measuring zero crossing of a power signal; and a communication unit, in communication with the metrology unit for collecting zero crossing measurements and communicating count stamped messages including the collected zero crossing measurements to a remote node for determining relative phase between the power meter and another power meter; wherein the communication unit is in communication with a local clock for count-stamping messages upon transmission. ### Claim 13 A power meter comprising: a metrology unit for measuring zero crossing of a power signal; and a communication unit, in communication with the metrology unit for collecting zero crossing measurements and communicating count stamped messages including the collected zero crossing measurements to a remote node for determining relative phase between the power meter and another power meter; wherein the communication unit is in communication with a local clock for count-stamping messages upon receipt. ### Claim 14 A power meter comprising: a metrology unit for measuring zero crossing of a power signal; and a communication unit, in communication with the metrology unit for collecting zero crossing measurements and communicating count stamped messages including the collected zero crossing measurements to a remote node for determining relative phase between the power meter and another power meter; wherein the communication unit is in communication with a second power meter for receiving count-stamped messages and for determining phase relative to the second power meter. ### Claim 15 A power meter comprising: a metrology unit for measuring zero crossing of a power signal; a communication unit, in communication with the metrology unit for collecting zero crossing measurements and communicating count stamped messages including the collected zero crossing measurements to a remote node for determining relative phase between the power meter and another power meter; and a first clock for providing time for the zero crossing and a second clock for count-stamping the messages.