ELECTRICITY METER HOT SOCKET DETECTION

• US 20140327449A1
• Filed: 04/29/2014
• Published: 11/06/2014
• Est. Priority Date: 05/01/2013
• Status: Active Grant

• Current Assignee: Elster Solutions LLC (Honeywell International Inc.)
• Original Assignee: Elster Solutions LLC (Honeywell International Inc.)
• Inventors: Shuey, Kenneth C., Mason, Robert T. Jr.
• Granted Patent: US 9,733,294 B2
• Time in Patent Office: Days
• US Class Current: 324/538
• CPC Class Codes: G01R 22/063 related to remote communication
• CPC Class Codes: G01R 22/068 Arrangements for indicating or signaling faults
• CPC Class Codes: G01R 31/1227 of components, parts or materials G01R31/1209, G01R31/1218, G01R31/18 take precedence; circuits therefor G01R31/14; testing vessels of electrodes G01R31/16
• CPC Class Codes: G01R 31/69 of terminals at the end of a cable or a wire harness; of plugs; of sockets, e.g. wall sockets or power sockets in appliances

Abstract

When a poor meter to socket connection occurs, there is the potential for arcing to develop which can result in a hot socket and a fire. Disclosed herein are methods for a meter to detect the occurrence of an arc condition in the socket by analyzing the RF noise on the channels of the communication spectrum used by the meter to communicate within its metering system. For example, by keeping a record of the normal background noise and looking for a broadband increase in the noise on all channels, arc detection can be achieved. Meter quantities such as temperature, current, voltage, and harmonic content may also be used in a standalone manner or in combination with broadband RF noise to detect an arc condition. A disconnect switch within the meter can be opened to remove the arc fault.

Claims

1. An electricity meter for metering electrical energy delivered from a voltage source to an electrical load, said meter disposed between said voltage source and said electrical load, the meter comprising:

blades for connecting the electricity meter to a socket;

a transceiver that communicates wirelessly on a plurality of channels of an RF communication system, the transceiver measuring received signal strength on at least some of the plurality of channels and generating a received signal strength indicator (RSSI) value indicative of the received signal strength on those channels; and

a processor that receives the RSSI values from the transceiver and determines therefrom whether an arc condition exists between the blades and the socket.

2. The electricity meter of claim 1, wherein the RF communication system comprises an ISM mesh networking system.

3. The electricity meter of claim 2, wherein the ISM mesh networking system comprises a utility, wherein the utility is signaled when the processor determines that an arc condition exists.

4. The electricity meter of claim 1, wherein the processor generates a warning signal when an arc condition is determined to exist.

5. The electricity meter of claim 1, further comprising an internal disconnect switch, wherein when an arc condition is determined to exist, the processor operates the internal disconnect switch to an open position to remove a meter load and thereby eliminate the arc condition.

6. The electricity meter of claim 5, wherein the meter is configured to verify that the arc condition has been removed.

7. The electricity meter of claim 1, wherein the transceiver is in close proximity to the blades.

8. The electricity meter of claim 1, wherein the processor determines whether an arc condition exists within 1 millisecond.

9. The electricity meter of claim 1, wherein the transceiver detects RSSI values in the ISM 900 MHz band.

10. The electricity meter of claim 1, wherein the metering processor is configured to determine that an arc condition exists when at least 70% of the RSSI values measured by the transceiver on the channels of the RF communication system are determined to have increased by at least 10 db.

11. The electricity meter of claim 1, wherein the meter is configured to store a record of RSSI values for each communication channel, and the processor is configured to determine whether an arc condition exists by comparing the stored RSSI values for a communication channel with more recently measured RSSI values of the same communication channel at the peak and at or near the zero crossing of a current or voltage waveform.

12. The electricity meter of claim 1, wherein the processor is configured to receive temperature, current, voltage, and harmonic content and determine therefrom, in combination with the RSSI values, whether an arc condition exists.