Apparatus and method to detect tampering with an electronic utility meter

• US 5,940,009 A
• Filed: 09/08/1997
• Issued: 08/17/1999
• Est. Priority Date: 09/08/1997
• Status: Expired due to Term

• Current Assignee: Elster Electricity LLC (Honeywell International Inc.)
• Original Assignee: ABB Power T&D Limited (ABB Limited)
• Inventors: Shuey, Kenneth C., Hemminger, Rodney C., Loy, Garry M., Munday, Mark L.
• Primary Examiner(s): Horabik, Michael
• Assistant Examiner(s): WONG, ALBERT KANG
• Application Number:
  US08/925,542
• Time in Patent Office: 708 Days
• Field of Search: 340/870.02, 340/870.03, 340/568, 340/571, 324/110, 364/483, 375/200, 250/222.1
• US Class Current: 340/870.02
• CPC Class Codes: G01R 22/066 Arrangements for avoiding or indicating fraudulent use

Abstract

An apparatus and method for detecting tampering with an electrical energy meter comprising a disconnect switch, interposed into feeder lines that deliver electrical energy from a voltage source to an electrical load, which switches between an open circuit in which electrical energy is not supplied to the electrical load and a closed circuit in which electrical energy is supplied to the electrical load, a load-side voltage sensor, which provides voltage signals indicative of load-side voltage, and a microprocessor that determines whether a tamper conditions exists by determining whether the disconnect switch is open or closed, determining whether a load-side voltage is present, and, if the disconnect switch is open and a load-side voltage is present, indicating that a tamper condition exists. The tamper detection apparatus preferably includes a communications module, connected to the microprocessor, for providing a two-way communications interface to a remote location. In this embodiment, if the microprocessor determines that a tamper condition exists, the microprocessor transmits to the remote location a message indicating that a tamper condition exists. The communications module may also open or close the disconnect switch in response to open and close commands from the remote location. This feature permits remote polling of the meter to determine if a tamper condition is present.

Claims

1. Apparatus for detecting tampering with an electrical energy meter, said meter metering electrical energy delivered from a voltage source via feeder lines to an electrical load at a subscriber location, said meter disposed between said voltage source and said electrical load, the apparatus comprising:

a disconnect switch, interposed into said feeder lines, for switching between an open circuit in which electrical energy is not supplied to said electrical load and a closed circuit in which electrical energy is supplied to said electrical load;

a load-side voltage sensor, which provides voltage signals indicative of load-side voltage on a side of said disconnect switch connected to said electrical load; and

a microprocessor, responsive to said voltage signals, which determines whether a tamper conditions exists by;

a) determining whether said disconnect switch is open or closed;

b) determining whether said load-side voltage is present; and

c) if said disconnect switch is open and said load-side voltage is present, indicating that a tamper condition exists.

2. The apparatus of claim 1, further comprising:

a communications module, connected to said microprocessor, for providing a two-way communications interface to a remote utility monitoring location, wherein, if said microprocessor determines that a tamper condition exists, said microprocessor transmits via said communications module to said remote utility monitoring location a message indicating that a tamper condition exists.

3. The apparatus of claim 2, wherein said disconnect switch is responsive to said microprocessor, said communications module receives open and close commands from said remote utility monitoring location, and said microprocessor opens or closes said disconnect switch in response to said open and close commands, respectively.

4. The apparatus of claim 2, wherein said communications module is a radio frequency transceiver.

5. The apparatus of claim 2, wherein said communications module is an interface to telephone lines located at said subscriber location.

6. The apparatus of claim 2, wherein said communication module is an interface to power lines located at said subscriber location.

7. A system for remotely detecting tampering comprising:

1) a meter which meters electrical energy delivered from a voltage source via feeder lines to an electrical load, said meter disposed between said voltage source and said electrical load, said meter comprising;

a) a disconnect switch, interposed into said feeder lines, for switching between an open circuit in which electrical energy is not supplied to said electrical load and a closed circuit in which electrical energy is supplied to said electrical load;

b) a load-side voltage sensor, which provides voltage signals indicative of load-side voltage on a side of said disconnect switch connected to said electrical load;

c) a microprocessor, responsive to said voltage signals, which determines whether said disconnect switch is open or closed and whether said load-side voltage is present, said disconnect switch being responsive to said microprocessor; and

d) a communications module, connected to said microprocessor, for providing a two-way communications interface; and

2) a remote utility monitoring location interfaced via a communications link to said communications module of said meter, said remote utility monitoring location issuing an open command to said meter to open said disconnect switch, receiving a signal from said communications module indicating whether a load-side voltage exists on a side of said disconnect switch connected to said electrical load; and

if a load-side voltage exists while said disconnect switch is opened, said remote utility monitoring location indicating that a tamper condition exists.

8. A method of detecting tampering with an electrical energy meter, said meter metering electrical energy delivered from a voltage source via feeder lines to an electrical load at a subscriber location, said meter situated at a point between said voltage source and said electrical load and including a disconnect switch, interposed into said feeder lines, for switching between an open circuit in which electrical energy is not supplied to said electrical load and a closed circuit in which electrical energy is supplied to said electrical load, the method comprising the steps of:

a) determining whether said disconnect switch is open or closed;

b) determining whether a load-side voltage is present on a side of said disconnect switch connected to said electrical load; and

c) if said disconnect switch is open and said load-side voltage is present, indicating that a tamper condition exists.

9. The method of claim 8, comprising the further step of:

if a tamper condition exists, said meter communicating a message via a communications module to a remote utility monitoring location, said message indicating that a tamper condition exists.

10. A method of detecting tampering with an electrical energy meter, said meter metering electrical energy delivered from a voltage source via feeder lines to an electrical load at a subscriber location, said meter disposed between said voltage source and said electrical load, said meter having a communications module for two-way communications with a remote utility monitoring location and a disconnect switch interposed into said feeder lines, for switching between an open circuit in which electrical energy is not supplied to said electrical load and a closed circuit in which electrical energy is supplied to said electrical load, the method comprising the steps of:

said remote utility monitoring location issuing an open command to said meter;

said meter opening said disconnect switch in response to said open command;

said meter determining whether a load-side voltage exists on a side of said disconnect switch connected to said electrical load;

if a load-side voltage exists, said meter sending via said communications module an indicator to said remote utility monitoring location indicating that a tamper condition exists; and

said meter closing said disconnect switch.

11. The method of claim 10, wherein said closing step comprises the steps of:

said remote utility monitoring location issuing a close command to said meter; and

said meter closing said disconnect switch in response to said close command.