A SYSTEM AND METHOD FOR INFERRING SCHEMATIC AND TOPOLOGICAL PROPERTIES OF AN ELECTRICAL DISTRIBUTION GRID

• US 20140233662A1
• Filed: 04/26/2013
• Published: 08/21/2014
• Est. Priority Date: 02/19/2013
• Status: Active Grant

• Current Assignee: Dominion Enterprises (Landmark Media Enterprises LLC), TRC Companies Incorporated
• Original Assignee: Power Tagging Technologies, Inc.
• Inventors: BERNHEIM, Henrik F., ABENDSCHEIN, Andrew Louis, HANSELL, Jerritt, LIAO, YU, MARTIN, Marcia Reid
• Granted Patent: US 10,097,240 B2
• Time in Patent Office: Days
• US Class Current: 375/258
• CPC Class Codes: G01R 29/18 Indicating phase sequence; Indicating synchronism
• CPC Class Codes: G05B 13/02 electric
• CPC Class Codes: G06Q 50/06 Energy or water supply
• 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 2203/5433 Remote metering
• CPC Class Codes: H04B 2203/5466 using three phases conductors
• CPC Class Codes: H04B 3/54 Systems for transmission via power distribution lines
• CPC Class Codes: H04B 3/542 the information being in digital form
• CPC Class Codes: H04B 3/546 Combination of signalling, telemetering, protection circuits for remote indication of supply or distribution network condition H02J13/00
• CPC Class Codes: H04L 1/0009 by adapting the channel coding H04L1/1812 takes precedence
• CPC Class Codes: H04L 1/188 Time-out mechanisms
• CPC Class Codes: H04L 41/0803 Configuration setting
• CPC Class Codes: H04L 41/083 for increasing network speed
• CPC Class Codes: H04L 41/12 Discovery or management of network topologies
• CPC Class Codes: H04L 43/0847 Transmission error
• CPC Class Codes: Y02E 60/00 Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
• CPC Class Codes: Y04S 10/16 Electric power substations
• CPC Class Codes: Y04S 40/00 Systems for electrical power generation, transmission, distribution or end-user application management characterised by the use of communication or information technologies, or communication or information technology specific aspects supporting them
• CPC Class Codes: Y04S 40/121 using the power network as support for the transmission

Abstract

A system and method for inferring schematic and topological properties of an electrical distribution grid is provided. The system may include Remote Hubs, Subordinate Remotes, a Substation Receiver, and an associated Computing Platform and Concentrator. At least one intelligent edge transmitter, called a Remote Hub Edge Transmitter, may transmit messages on the electrical distribution grid by injecting a modulated current into a power main that supplies an electric meter. The Subordinate Remotes, Remote Hubs, the Substation Receiver, and the associated Computing Platform and Concentrator may contain processing units which execute stored instructions allowing each node in the network to implement methods for organizing the on-grid network and transmitting and receiving messages on the network. The Substation Receiver, Computing Platform and Concentrator may detect and infer schematic grid location attributes of the network and publish the detected and inferred attributes to other application systems including geospatial information systems maintaining the logical and physical network model.

Claims

1. A system for sending and receiving messages on an electrical distribution grid from the low-voltage periphery of said grid to an electrical distribution substation without requiring intervening apparatus to repeat or amplify the signal and wherein said grid is used as a long-range data-bearing network, the system comprising:

a. a converged network comprising at least one conventional network and at least one medium voltage electrical distribution grid, wherein the at least one medium voltage electrical distribution grid comprises at least one distribution substation containing at least one distribution transformer, and at least one low-voltage network comprising a service transformer supplying power to at least one consumer;

b. a data center comprising a database containing a Grid Map and an Inventory and stored programs, attached to the conventional network;

c. at least one Computing Platform for each of the at least one distribution substations containing at least one substation transformers, the Computing Platform comprising a database containing a subset of the Grid Map and a subset of the Inventory and stored programs;

d. at least one Substation Receiver hosted on or in communication with the at least one Computing Platform; and

e. at least one Transformer Area Network supplied with power by the at least one distribution substation transformer, each Transformer Area Network comprising at least one Remote Hub sited on the low-voltage side of the service transformer, wherein the Remote Hub is configured to transmit messages that are received and decoded by the Substation Receiver, without the use of repeaters, bridges, or other apparatus between the Substation Receiver and the at least one Remote Hub.

2. The system of claim 1, wherein a Transformer Area Network contains one or more Subordinate Remotes on the low voltage side of said service transformer, wherein the one or more subordinate remotes are operable to respond to discovery commands and data collection requests from the at least one Remote Hub via an on-grid protocol.

3. The system of claim 1, further comprising providing a Substation-to-Edge channel by an Advanced Metering Infrastructure.

4. The system of claim 1, further comprising providing a Substation-to-Edge channel by at least one on-grid transmitter configured to transmit from medium or high voltage to low voltage.

5. The system of claim 1, wherein the Data Center further comprises a Head End of an Advanced Metering Infrastructure attached to the conventional network, and a Concentrator configured to provide data blocks to the Head End for broadcast over the Advanced Metering Infrastructure and received by the Remote Hubs.

6. The system of claim 1, wherein the Transformer Area Network is bounded by a single-phase service transformer.

7. The system of claim 1, wherein the service transformer is a multi-phase service transformer, and wherein the service area of the multi-phase service transformer contains one Transformer Area Network for each phase of the multi-phase service transformer.

8. The system of claim 1, wherein the service transformer is a multi-phase service transformer, and wherein the service area of the multi-phase service transformer contains a single Transformer Area Network, with a master Remote Hub on one phase of the service transformer, and a Proxy Hub on each phase of said transformer not having the master Remote Hub.

9. The system of claim 1, wherein a Remote Hub is programmable by a portable computing device and a local interface.

10. The system of claim 1, wherein data can be collected from a Remote Hub by a portable computing device and a local interface.

11. The system of claim 1, wherein at least one additional Substation Receiver is sited at an intermediate point on the medium voltage distribution grid between the at least one Transformer Area Network and the at least one substation transformer.

92. The system of claim 1, wherein the Remote Hub has a Global Positioning System receiver.

93. The system of claim 1, wherein at least one Subordinate Remote has a Global Positioning System receiver.

12. A method for inferring schematic and topological properties of an electrical distribution grid which vary over time, comprising transmitting messages from a Remote Hub connected at low voltage on a single phase main in a Transformer Area Network to an electrical distribution substation without requiring intervening apparatus to repeat or amplify the signal, the method comprising the steps of:

a. identifying at least one frequency band in the candidate spectrum to form at least one transmission channel on the distribution grid;

b. loading the Remote Hub with information defining a policy for allowing said Remote Hub to transmit on the at least one channel;

c. obtaining a data payload;

d. creating a message from the data payload and including information in the message to be transmitted to facilitate detection of the message and inference of the grid location of the transmitter; and

e. transmitting the message onto the power line by injecting a modulated current signal into the at least one channel.

13. The method of claim 12, wherein the data payload comprises a bit stream, and wherein forward error correction bits are computed on the data payload and appended to the bit stream.

14. The method of claim 12, wherein the data payload comprises a bit stream, and wherein forward error correction bits are computed on the data payload and interleaved with the data bits of the bit stream in a pattern.

15. The method of claim 12, wherein the message contains a preamble, a data payload, and a probe transmission for establishing grid location.

16. The method of claim 15, wherein the probe transmission is contained in the preamble.

17. The method of claim 15, wherein the probe transmission is separate from the preamble.

18. The method of claim 15, wherein bandwidth of the preamble is the same as that of the data payload.

19. The method of claim 15, wherein bandwidth of the preamble is different than the data payload.

20. The method of claim 15, wherein the probe transmission comprises a sequence of at least one broadband modulated signal.

21. The method of claim 15, wherein the probe transmission comprises a sequence of at least one sweeping group comprising at least one tone.

22. The method of claim 12, further comprising providing a provisioning request in the data payload.

23. The method of claim 12, further comprising describing discovery of a new Subordinate Remote in the data payload.

24. The method of claim 12, wherein the data payload contains at least one computed result derived from data measured at the Remote Hub.

25. The method of claim 12, wherein the data payload contains at least one computed result derived from data measured on at least one Subordinate Remote.

26. The method of claim 12, further comprising including at least one report of an exceptional condition detected in a Transformer Area Network in the data payload.

27. The method of claim 12, further comprising including a retransmission of a previous data payload in the data payload.

28. The method of claim 12, wherein the at least one transmission channel is not divided into time slots and may be accessed by the Remote Hub at randomly selected times.

29. The method of claim 12, further comprising providing a plurality of Remote Hubs and synchronizing system clocks of all Remote Hubs within the plurality of Remote Hubs able to receive power from the same distribution substation.

30. The method of claim 29, wherein the at least one transmission channel is a slotted channel divided by provisioning into time slots of predetermined lengths.

31. The method of claim 30, wherein at least one of the time slots of the slotted channel is reserved for scheduled transmissions and assigned to the Remote Hub by provisioning.

32. The method of claim 30, wherein at least one of the time slots of the slotted channel is reserved for random transmissions and may be accessed by the Remote Hub.

33. The method of claim 12, wherein at least one channel is not divided into time slots.

34. The method of claim 12, wherein the Remote Hub waits for a policy-based fixed interval of time plus a randomly selected interval of time, and then retransmits said message.

35. The method of claim 12, wherein the Remote Hub waits for a policy-based fixed interval of time plus a randomly selected interval of time, and then retransmits said message only if an acknowledgement of the message on a Substation-to-Edge channel has not been received.

36. The method of claim 32, wherein the Remote Hub waits for a policy-based fixed interval of time plus a randomly selected interval of time, and then retransmits said message in the then next available time slot reserved for random messages.

37. The method of claim 32, wherein the Remote Hub waits for a policy-based fixed interval of time plus a randomly selected interval of time, and then retransmits said message in the then next available time slot reserved for random messages only if an acknowledgement of the message on a Substation-to-Edge channel has not been received.

38. The method of claim 12, wherein the modulated current signal is modulated by a combination of more than one modulation technique.

39. The method of claim 12, wherein the modulated current signal is modulated by a spread frequency method, and further comprising assigning at least one chip to the at least one channel for the purpose of modulating transmissions.

40. The method of claim 39, further comprising selecting the chip at random from a plurality of mathematically orthogonal chips assigned to the at least one channel for the purpose of modulating transmissions.

41. The method of claim 39, further comprising selecting the chip from a plurality of mathematically orthogonal chips assigned to the at least one channel by the ordinal of the time slot in which the message is to be transmitted.

42. The method of claim 39, wherein the message is modulated onto the channel by computing the exclusive OR of the chip and the message string.

43. The method of claim 39, further comprising a plurality of Remote Hubs each uniquely assigned one of a set of mutually orthogonal chips.

44. The method of claim 12, further comprising using a shaping filter in the transmission of the message to avoid injecting energy on harmonics of a power fundamental signal.

45. The method of claim 12, further comprising storing a message until the information defining a policy permits transmission.

46. The method of claim 12, further comprising closing an isolation circuit prior to transmitting so that current may flow from an Edge Transmitter in the Remote Hub onto the power line.

47. The method of claim 46, wherein closing said isolation circuit further comprises closing a Triac at a zero crossing of the power line fundamental, then closing a relay.

48. The method of claim 46, further comprising opening said isolation circuit after the transmission message has been completely transmitted.

49. The method of claim 48, wherein opening said isolation circuit further comprises the steps of opening the relay, then opening the Triac at a zero crossing of the power line fundamental.

50. The method of claim 12, wherein the information defining a policy is provided to the Remote Hub during manufacture.

51. The method of claim 12, wherein the information defining a policy is transmitted to the Remote Hub over a Substation-to-Edge channel.

52. The method of claim 12, wherein the information defining a policy is transmitted to the Remote Hub from a hand-held device over a local interface.

53. The method of claim 12, wherein the information defining a policy is transmitted to the Remote Hub from a drive-by transmitter over a local interface.

94. The method of claim 12, wherein the data payload includes the geospatial coordinates of the Remote Hub.

95. The method of claim 12, wherein the data payload includes a computed function of the geospatial coordinates of the Remote Hub.

96. The method of claim 29, wherein synchronizing system clocks comprises using a Global Positioning System signal.

54. A method for receiving a message transmitted from a Remote Hub situated on the low voltage side of a service transformer on one of at least one frequency band channel known to both the Remote Hub and a Substation Receiver, the method comprising:

a. connecting the Substation Receiver to a bus of at least one substation transformer, wherein the Substation Receiver is connected by attaching current sensors to each of the three phases of at least one feeder attached to the bus;

b. monitoring the output of each current sensor and digitizing waveforms detected thereon;

c. detecting at least one message preamble in the digitized waveforms from at least one current sensor;

d. extracting a message from the digitized waveforms based on the detection of the at least one message preamble;

e. demodulating the message and forwarding the demodulated message to a Computing Platform;

f. determining information about the grid location of the transmitter of the received signals; and

g. extracting data from the message to derive additional information about the transmitter and any associated devices.

55. The method of claim 54, wherein a copy of at least one message is detected on at least one of the current sensors.

56. The method of claim 55, further comprising associating each detected copy of a message with at least one measurement of the properties of the copy.

57. The method of claim 56, wherein the at least one measurement describes a signal quality of the copy.

58. The method of claim 56, wherein the at least one measurement describes a bit error rate of the copy.

59. The method of claim 56, wherein the at least one measurement describes an amplitude versus frequency of the copy.

60. The method of claim 56, wherein the measurements associated with each detected copy of the message are forwarded to the Computing Platform.

61. The method of claim 55, further comprising associating other properties of the detected message with each copy of said message and forwarding the copies and associated properties to the Computing Platform.

62. The method of claim 61, further comprising forwarding the time said message was received to the Computing Platform.

63. The method of claim 61, further comprising forwarding an identity of the current sensor on which each copy of said message was received to the Computing Platform.

64. The method of claim 54, further comprising processing data regarding the message to infer the feeder and phase on which the message was transmitted by a Remote Hub.

65. The method of claim 54, further comprising applying a comb filter to the digitized waveforms to remove harmonics of the power fundamental.

66. The method of claim 54, wherein an entire candidate spectrum is sampled in order to detect preambles.

67. The method of claim 54, wherein only selected frequency bands are sampled in order to detect preambles.

68. The method of claim 63, wherein the Computing Platform identifies the transmitter of a message from a combination of the properties of a received message and the data content of the message.

69. The method of claim 63, further comprising the Computing Platform searching an Inventory of transformers for the transmitter.

70. The method of claim 69, further comprising the Computing Platform adding the transmitter to the Inventory when the transmitter is not located in the search of the Inventory.

71. The method of claim 70, further comprising the Computing Platform adding the transmitter and the grid location of said transmitter to a Grid Map.

72. The method of claim 69, further comprising the Computing Platform locating the transmitter in the Inventory.

73. The method of claim 72, further comprising the Computing Platform retrieving a previously stored grid location of the transmitter from a Grid Map.

74. The method of claim 73, further comprising the Computing Platform comparing the inferred grid location of the received message with a retrieved previous grid location of the transmitter.

75. The method of claim 74, further comprising the Computing Platform updating the Grid Map with the new grid location of the transmitter.

76. The method of claim 61, further comprising the Computing Platform forwarding information regarding a received message over a conventional network to a Concentrator.

77. The method of claim 76, further comprising the Concentrator using said forwarded information to update its Inventory.

78. The method of claim 76, further comprising the Concentrator using said forwarded information to update its Grid Map.

79. The method of claim 76, further comprising the Concentrator determining whether to send said forwarded information over a conventional network to at least one other application.

80. The method of claim 54, further comprising archiving the digitized output of each current sensor for later analysis.

81. The method of claim 54, further comprising processing and enhancing the extracted message, data, and additional information, and archiving the processed and enhanced information and data for later analysis.

82. The method of claim 54, wherein the steps of the procedure are divided into a plurality of sequenced and parallel processes to make use of multiple available processor cores to detect and process sequences of transmissions arriving on multiple frequency bands on multiple inputs, comprising the steps of:

a. writing the digitized signals with a timestamp from each monitored phase of each monitored feeder to a protected memory buffer;

b. reading the digitized signals and dividing the signals into at least one channel according to the provisioning of the distribution grid to create channelized data,

c. discarding data which is not part of any defined channel;

d. writing the channelized data into a protected memory buffer;

e. reading the channelized data from the protected memory buffer and sampling the data to detect at least one preamble pattern which indicates the beginning of a message;

f. creating a record marking the locations in the channel data of each copy of the starting point of a transmission;

g. conveying said record containing the marked locations to a demodulator;

h. demodulating each copy of the transmission to create a demodulated message;

i. applying an error correction method;

j. writing the demodulated message and measured and inferred information about the message onto a protected memory buffer; and

k. signaling the completion of each step so as to allow data representing the outcome of said step to become available to a processor executing the next step in the process.

83. The method of claim 54, wherein said current sensors are attached to Supervisory Control and Data Acquisition loops already present on each phase of the at least one feeder attached to the bus of a substation transformer.

84. The method of claim 54, wherein said current sensors are coupled directly to main lines of each phase of the at least one feeder.

85. The method of claim 54, wherein a demodulator attempts to demodulate the message using each possible value of a chip which a transmitter is permitted by policy to use.

86. The method of claim 54, wherein detecting at least one preamble comprises only scanning for possible preambles during a fixed section of a time slot.

87. The method of claim 54, wherein detecting at least one preamble comprises continuously scanning for possible preambles.

88. The method of claim 54, wherein a second Substation Receiver is placed at an intermediate point on the medium voltage distribution grid.

89. The method of claim 88, further comprising said second Substation Receiver collecting data to determine the set of Transformer Area Networks which receive power from the Substation Transformer by way of the intermediate point.

90. The method of claim 88, wherein a Remote Hub is in communication with the second Substation Receiver.

91. The method of claim 90, wherein the Remote Hub and the second Substation Receiver are employed to exert local control on a portion of the electrical distribution grid.