Monitoring electrical assets for fault and efficiency correction

• US 8,587,445 B2
• Filed: 04/08/2010
• Issued: 11/19/2013
• Est. Priority Date: 09/13/2006
• Status: Active Grant

• Current Assignee: Aclara Technologies LLC (Hubbell, Inc.)
• Original Assignee: Daniel J. Rockwell
• Inventors: Rockwell, Daniel J.
• Primary Examiner(s): Nguyen, Tai T
• Application Number:
  US12/756,256
• Publication Number:
  US 20100188239A1
• Time in Patent Office: 1,321 Days
• Field of Search: 340/635, 340/636.1, 340/638, 340/505, 340/506, 340/521, 340/540, 340/3.1, 340/5.6, 340/8.1, 702 57- 59, 702/62, 324/126, 324/142
• US Class Current: 340/635
• CPC Class Codes: G01R 19/2513 Arrangements for monitoring electric power systems, e.g. power lines or loads; Logging
• CPC Class Codes: G01R 31/086 in power transmission or distribution networks, i.e. with interconnected conductors
• CPC Class Codes: G01R 31/088 Aspects of digital computing
• CPC Class Codes: G01R 31/50 Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections testing of sparking plugs H01T13/58
• CPC Class Codes: G01R 31/52 Testing for short-circuits, leakage current or ground faults
• CPC Class Codes: H02H 7/28 for meshed systems

Abstract

A system and method of monitoring a plurality of electrical assets comprise an electricity distribution infrastructure, including a plurality of electrical asset sensors coupled to the electrical assets for monitoring an operating condition of the electrical assets as well as any fault conditions. The sensors may include a current transformer for obtaining a current waveform, a GPS receiver for applying a synchronized time-stamp to the waveform data, and a mesh network radio for transmitting the time-stamped waveform data. Data from the plurality of sensors may be encrypted and transmitted over a mesh network to one or more gateways that are in communication with a central command processor. In response to an abnormal operating condition of any electrical asset, the central command processor may determine a probable fault location, a probable fault type, and a fault response.

Claims

1. A system for monitoring a plurality of electrical assets defining an electrical infrastructure, the system comprising:

a plurality of electrical asset monitors coupled to respective ones of the electrical assets, each monitor including a sensor coupled to the electrical asset for obtaining data corresponding to at least one of a voltage, current, and phase angle waveforms, a globally synchronized timer, a mesh network radio, a power supply, and a power storage device;

one or more gateways, each gateway including a gateway mesh network radio for communicating with the plurality of electrical asset monitors and a network interface for communicating with a central command center via a network distinct from the mesh network;

the central command center including a further network interface for communicating with the one or more gateways, a memory for storing a database of fault signatures, a second memory for storing the obtained data, and a processor for analyzing the obtained data to identify a probable fault type, a probable fault location, and a fault response; and

a mesh network for routing communications among the plurality of electrical asset monitors and the one or more gateways, whereby the mesh network coordinates efficient communication paths among the plurality of electrical asset monitors and the one or more gateways.

2. The system of claim 1, wherein each one of the plurality of electrical asset monitors include a processor configured to implement an encryption scheme to encrypt the data before it is communicated by the mesh network radio.

3. The system of claim 2, wherein each one of the one or more gateways includes a processor configured to implement the encryption scheme to decrypt the data from the plurality of electrical asset monitors and to encrypt the data according to a further encryption scheme before it is communicated by the network interface.

4. The system of claim 2, wherein:

the encryption scheme is one of a tree group Diffie-Hellman protocol, an RSA protocol, and an elliptic-curve cryptography protocol;

the encryption processor is configured to encrypt communications with the one or more gateways according to an advanced encryption standard (AES), data encryption standard (DES), Blowfish, Twofish, or triple DES; and

the central command center processor is configured to decrypt communications originating from the plurality of electrical asset monitors.

5. The system of claim 1, wherein the mesh network is configured according to a ZigBee protocol.

6. The system of claim 1, wherein the mesh network is configured according to an ad-hoc Wi-Fi protocol and efficient communication paths are coordinated according to an ad-hoc on-demand distance vector (AODV) algorithm.

7. The system of claim 1, wherein the central command center processor is configured to correlate the data to the database of fault signatures to identify the probable fault type.

8. The system of claim 7, wherein the central command center processor is configured to generate a fault warning, wherein the fault warning includes the probable fault location and the probable fault type.

9. The system of claim 8, wherein the fault warning is at least one of a fax, an e-mail, a pager message, an audiovisual warning, a network alert, an SMS message, and a Simple Object Access Protocol (SOAP) message.

10. The system of claim 1, wherein the fault is an unbalanced power factor and the central command center processor is configured to initiate one or more predetermined power factor correction algorithms.

11. The system of claim 1, wherein the fault is an electrical asset failure and the central command center processor is configured to initiate one or more predetermined electrical asset isolation algorithms.

12. The system of claim 1, wherein the fault is an electrical asset overload and the central command center processor is configured to initiate one or more predetermined electrical asset bypass algorithms.

13. The system of claim 1, wherein each monitor of the plurality of electrical asset monitors further includes a GPS receiver for synchronizing the globally synchronized timer and obtaining a plurality of coordinates corresponding to a location of the monitor.

14. A system for monitoring a plurality of electrical assets defining an electrical infrastructure for pin pointing fault locations the system comprising:

a plurality of electrical asset monitors coupled to respective ones of the electrical assets, each monitor including a sensor coupled to the electrical asset for obtaining data corresponding to at least ones of a voltage, current, or a phase angle waveform, a globally synchronized timer to time stamp the data, to measure time and to provide position information, a mesh network radio, a power supply, and a power storage device;

one or more gateways, each gateway including a gateway mesh network radio for communicating with the plurality of electrical asset monitors and a network interface for communicating with a central command center via a network distinct from the mesh network;

the central command center including a further network interface for communicating with the one or more gateways, a memory for storing a database of fault signatures, a second memory for storing the obtained data, a third memory for storing fixed asset information that includes at least one of cable type, cable propagation velocity, cable segment length, or asset type and asset electrical impedance, and a processor for analyzing the obtained data to identify a probable fault type, a probable fault location, and a fault response;

where

a system is configured to calculate a fault location from the globally synchronized times and at least one of respective arrival times of the fault signal from multiple ones of the plurality of electrical asset monitors, asset monitor position, fault signal propagation, and cable segment lengths.