Electrical network topology determination

Patent metadata

Field	Value
Publication number	US-9835662-B2
Application number	US-201414558571-A
Country	US
Kind code	B2
Filing date	Dec 2, 2014
Priority date	Dec 2, 2014
Publication date	Dec 5, 2017
Grant date	Dec 5, 2017

Abstract

Determination of electrical network topology and connectivity are described herein. A zero-crossing is indicated at a time when the line voltage of a conducting wire in an electrical grid is zero. Such zero-crossings may be used to measure time within a smart grid, and to determine the connectivity of, and the electrical phase used by, particular network elements. A first meter may receive a phase angle determination (PAD) message, including zero-crossing information, sent from a second meter, hereafter called a reference meter. The first meter may compare the received zero-crossing information to its own zero-crossing information. A phase difference may be determined between the first meter and the reference meter from which the PAD message originated. The first meter may pass the PAD message to additional meters, which propagate the message through the network. Accordingly, an electrical phase used by meters within the network may be determined.

First claim

What is claimed is:

1. A method, comprising:
detecting a first voltage event comprising a measured voltage exceeding a threshold voltage, the first voltage event occurring at a first time relative to a first zero crossing at a first meter;
receiving at the first meter, a phase angle determination (PAD) message sent from a second meter, wherein the PAD message comprises an indication of a second voltage event comprising a measured voltage exceeding the threshold voltage, the second voltage event occurring at a second time relative to a second zero crossing at the second meter;
comparing the first time to the second time; and
determining, based on the comparing, if the first voltage event sensed by the first meter and the second voltage event sensed by the second meter are the same event.

2. The method of claim 1 , additionally comprising:
transmitting data, indicating if the first voltage event and the second voltage event are the same event, to a central office.

3. The method of claim 1 , wherein the PAD message comprises an elapsed period between the second zero-crossing and the second voltage event.

4. The method of claim 1 , wherein the PAD message comprises degrees between the second zero-crossing and the second voltage event.

5. The method of claim 1 , wherein the received PAD message comprises a measure of time between the second zero-crossing and the second voltage event.

6. The method of claim 1 , wherein the first zero-crossing and the second zero crossing are based at least in part on a direction, positive-to-negative or negative-to-positive, of a zero-crossing of voltage on an electric grid.

7. The method of claim 1 , additionally comprising:
determining if a previous PAD message, based on a particular reference broadcast related to the received PAD message, was received at the first meter; and
transmitting a PAD message from the first meter, if no previous PAD message based on the particular reference broadcast was received.

8. A node, comprising:
a transceiver; and
a processing unit communicatively coupled to the transceiver, the processing unit programmed to perform operations comprising:
detecting a first voltage event comprising a measured voltage exceeding a threshold voltage, the first voltage event occurring at a first time relative to a first zero crossing at the node;

receiving, via the transceiver, a phase angle determination (PAD) message from a second node, wherein the PAD message comprises an indication of a second voltage event comprising a measured voltage greater than the threshold voltage, the second voltage event occurring at a second time relative to a second zero crossing at the second node;
comparing, by operation of the processing unit, the the first time to the second time; and
determining, by operation of the processing unit, if the first voltage event sensed by the node and the second voltage event sensed by the second node are the same event.

9. The node of claim 8 , wherein the processing unit is configured to cause a transmission of data to a neighboring node via the transceiver, and wherein the data transmitted comprises:
a time of the transmission, expressed at least in part using a zero-crossing; and
a phase difference between the node and a reference node.

10. The node of claim 8 , wherein the PAD message comprises:
a time of transmission of the received PAD message, based at least in part on zero-crossing of a node from which the PAD message was sent; and
a phase difference between the node from which the PAD message was sent and a reference node.

11. The node of claim 8 , additionally comprising:
a phase angle calculation module, executed by the processing unit, to create data for inclusion in an out-going PAD message, wherein the created data is based in part on the received PAD message, and wherein the out-going PAD message is transmitted to at least one other node in a network.

12. The node of claim 8 , additionally comprising:
a phase angle calculation module, executed by the processing unit, to create data for inclusion in an out-going PAD message, wherein the created data comprises a time of retransmission expressed at least in part with respect to a zero-crossing and a phase angle difference with respect to a reference node.

13. The node of claim 8 , additionally comprising a phase angle calculation module, executed by the processing unit, to compute a phase difference between the node and a reference node using data comprising:
a phase angle of a node from which the PAD message was received;
a phase angle of the node at a time of the PAD message; and
a phase angle difference between the node from which the PAD message was received and the reference node.

14. The node of claim 8 , additionally comprising:
a clock, in communication with the processing unit, to measure time since a last zero-crossing.

15. The node of claim 8 , wherein the PAD message comprises zero-crossing information that is based at least in part on a voltage level of an electrical power grid.

16. A network, comprising:
a plurality of nodes arranged in a mesh and in communication with one another via one or more communication links, the plurality of nodes being configured to measure zero-crossing of voltage in an electrical grid; and
a central office comprising one or more processors and memory, the memory storing instructions that, when executed, configure the central office to perform operations comprising:
receiving, at the central office, a phase angle determination (PAD) message from a first node, wherein the PAD message comprises an indication of a first voltage event comprising a measured voltage exceeding a threshold voltage, the first voltage event occurring at a first time relative to a first zero crossing at the first node;
receiving at the central office, a PAD message from a second node, wherein the PAD message comprises an indication of a second voltage event comprising a measured voltage exceeding the threshold voltage, the second voltage event occurring at a second time relative to a second zero crossing at the second node;
comparing the first time to the second time; and
determining, based on the comparing, if the first voltage event sensed by the first node and the second voltage event sensed by the second node are the same event.

17. The network of claim 16 , wherein at least one node of the plurality of nodes is additionally configured to relay PAD messages within the network.

18. The network of claim 16 , wherein comparing the first time to the second time is based on degrees between the first zero-crossing and the second zero crossing.

19. The network of claim 16 , wherein comparing the first time to the second time is based on a measure of time between the first zero-crossing and the second zero crossing.

20. The network of claim 16 , wherein the first zero-crossing and the second zero crossing are based at least in part on a direction, positive-to-negative or negative-to-positive, of a zero-crossing of voltage on an electric grid.

Assignees

• Itron Inc

Inventors

• Driscoll Timothy James
• Van Wyk Hartman
• Sonderegger Robert C
• Higgins Christopher M

Classifications

• G01R19/2513

  Arrangements for monitoring electric power systems, e.g. power lines or loads; Logging · CPC title

• G01D4/006

  Remote reading of utility meters to a non-fixed location, i.e. mobile location · CPC title

• G01D4/002 Primary

  Remote reading of utility meters · CPC title

• G01D4/004

  Remote reading of utility meters to a fixed location · CPC title

• G01R25/00 Primary

  Arrangements for measuring phase angle between a voltage and a current or between voltages or currents · CPC title