Electrical energy meters having real-time power quality measurement and reporting capability

• US 5,627,759 A
• Filed: 05/31/1995
• Issued: 05/06/1997
• Est. Priority Date: 05/31/1995
• Status: Expired due to Term

• Current Assignee: Landis+Gyr AG (Landis+Gyr Group AG)
• Original Assignee: Process Systems, Inc. (Crane Company)
• Inventors: Jenrette, William I., Randall, Bruce E., Bearden, Michael K.
• Primary Examiner(s): Cosimano, Edward R.
• Application Number:
  US08/455,477
• Time in Patent Office: 706 Days
• Field of Search: 324/103 R, 324/103 P, 324/142, 340/661, 364/464.04, 364/483, 364/492
• US Class Current: 702/62
• CPC Class Codes: G01R 19/2513 Arrangements for monitoring electric power systems, e.g. power lines or loads; Logging
• CPC Class Codes: H02J 13/00001 characterised by the display of information or by user interaction, e.g. supervisory control and data acquisition systems [SCADA] or graphical user interfaces [GUI]
• CPC Class Codes: H02J 13/00002 characterised by monitoring
• CPC Class Codes: H02J 13/00034 the elements or equipment being or involving an electric power substation
• CPC Class Codes: Y02E 60/00 Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
• CPC Class Codes: Y04S 10/30 State monitoring, e.g. fault, temperature monitoring, insulator monitoring, corona discharge
• CPC Class Codes: Y04S 10/40 Display of information, e.g. of data or controls
• CPC Class Codes: Y04S 10/52 Outage or fault management, e.g. fault detection or location

Abstract

A revenue accuracy meter and a method are provided for measuring the amount and quality of power received by a power customer across electrical power lines. The revenue accuracy meter preferably has a variation determiner for determining undesired variations in an electrical signal representative of power received by the power customer during a plurality of predetermined time periods. A power usage measurer is coupled in electrical communication with the variation determiner for measuring the power usage of a customer responsive to an electrical signal representative of a customer load. The meter further has a communications interface coupled in electrical communication with the variation determiner and the power usage measurer for communication signals representative of the power variations and the power usage. An energy management controller also preferably is connected to the communications interface for controlling power usage responsive to predetermined electrical command signals received from the power customer through the communications interface.

Claims

1. In an electrical energy meter containing means therein for metering a quantity of electrical energy generated by a supplier and transferred via a power supply line to a load of a customer during an energy measurement time interval, a method of monitoring variations in the metered quantity of electrical energy, comprising the steps of:

sensing a line voltage transferred via the power supply line to the load during the energy measurement time interval;

detecting an increase in a magnitude of the sensed line voltage from an acceptable voltage level to a level greater than a first surge threshold voltage, upon commencement of a surge time interval during which the magnitude of the sensed line voltage is at all times greater than the acceptable voltage level;

recording a surge event if the magnitude of the sensed line voltage exceeds the acceptable voltage level for a first predetermined amount of time after commencement of the surge time interval; and

then

communicating the recorded surge event to at least the supplier or customer before termination of the surge time interval.

2. The method of claim 1, further comprising the steps of capturing the sensed line voltage as a waveform during the surge time interval;

and communicating the waveform to the supplier before termination of the surge time interval.

3. The method of claim 1, wherein said detecting step comprises detecting an increase in a magnitude of the sensed line voltage from an acceptable voltage level to a level greater than a first surge threshold voltage, upon commencement of a surge time interval during which the magnitude of the sensed line voltage is at all times greater than at least a second surge threshold voltage intermediate the acceptable voltage level and the first surge threshold voltage.

4. The method of claim 1, wherein said communicating step comprises transferring data from a modem internal to the meter to a telephone line operatively connected thereto via a data port.

5. The method of claim 4, further comprising the steps of capturing the sensed line voltage as a waveform during the surge time interval;

and communicating the waveform to the supplier before termination of the surge time interval.

6. The method of claim 1, further comprising the steps of:

detecting a decrease in the magnitude of the sensed line voltage from the acceptable voltage level to a level less than a first sag threshold voltage, upon commencement of a sag time interval during which the magnitude of the sensed line voltage is at all times less than the acceptable voltage level;

recording a sag event if the magnitude of the sensed line voltage stays below the acceptable voltage level for a second predetermined amount of time after commencement of the sag time interval; and

then

communicating the recorded sag event to at least the supplier or customer before termination of the sag time interval.

7. The method of claim 6, wherein said step of detecting an increase comprises detecting an increase in a magnitude of the sensed line voltage from an acceptable voltage level to a level greater than a first surge threshold voltage, upon commencement of a surge time interval during which the magnitude of the sensed line voltage is at all times greater than at least a second surge threshold voltage intermediate the acceptable voltage level and the first surge threshold voltage;

and wherein said step of detecting a decrease comprises detecting a decrease in the magnitude of the sensed line voltage from the acceptable voltage level to a level less than a first sag threshold voltage, upon commencement of a sag time interval during which the magnitude of the sensed line voltage is at all times less than a second sag threshold voltage intermediate the acceptable voltage level and the first sag threshold voltage.

8. The method of claim 7, wherein said step of recording a surge event comprises recording a surge event if the sensed line voltage exceeds the second surge threshold voltage for a first predetermined amount of time after commencement of the surge time interval.

9. In an electrical energy meter containing means therein for metering a quantity of electrical energy generated by a supplier and transferred via a power supply line to a load of a customer during an energy measurement time interval, a method of monitoring variations in the metered quantity of electrical energy, comprising the steps of:

sensing a line voltage transferred via the power supply line to the load during the energy measurement time interval;

detecting an increase in a magnitude of the sensed line voltage from an acceptable voltage level to a level greater than a first surge threshold voltage, upon commencement of a surge time interval during which the magnitude of the sensed line voltage is at all times greater than the acceptable voltage level;

recording a surge event if the magnitude of the sensed line voltage exceeds the acceptable voltage level for a first predetermined amount of time after commencement of the surge time interval; and

then

communicating the recorded surge event to at least the supplier or customer promptly on a real time basis.

10. The method of claim 9, further comprising the steps of:

detecting a decrease in the magnitude of the sensed line voltage from the acceptable voltage level to a level less than a first sag threshold voltage, upon commencement of a sag time interval during which the magnitude of the sensed line voltage is at all times less than the acceptable voltage level;

recording a sag event if the magnitude of the sensed line voltage stays below the acceptable voltage level for a second predetermined amount of time after commencement of the sag time interval; and

then

communicating the recorded sag event to at least the supplier or customer promptly on a real time basis.

11. An electrical energy meter for reporting line voltage variations in real-time, comprising:

means for sensing a line voltage generated by a supplier and transferred via a power supply line to a load of a customer;

means, responsive to said sensing means, for detecting an increase in a magnitude of the sensed line voltage from an acceptable voltage level to a level greater than a first surge threshold voltage, upon commencement of a surge time interval during which the magnitude of the sensed line voltage is at all times greater than the acceptable voltage level;

means, responsive to said detecting means, for recording a surge event if the sensed line voltage exceeds the acceptable voltage level for a first predetermined amount of time after commencement of the surge time interval; and

means, responsive to said recording means, for communicating the recorded surge event to at least the supplier or customer before termination of the surge time interval.

12. The meter of claim 11, further comprising:

means, responsive to said sensing means, for detecting a decrease in the magnitude of the sensed line voltage from the acceptable voltage level to a level less than a first sag threshold voltage, upon commencement of a sag time interval during which the magnitude of the sensed line voltage is at all times less than the acceptable voltage level;

means, responsive to said means for detecting a decrease, for recording a sag event if the sensed line voltage stays below the acceptable voltage level for a second predetermined amount of time after commencement of the sag time interval; and

means, responsive to said means for recording a sag event, for communicating the recorded sag event to at least the supplier or customer before termination of the sag time interval.

13. The meter of claim 12, wherein said means for communicating the recorded surge event comprises a modem for transferring data from internal the meter to an external telephone line via a data port.

14. The meter of claim 13, wherein said means for recording a surge event comprises means for capturing the sensed line voltage as a waveform during the surge time interval;

and wherein said means for communicating the recorded surge event comprises means for communicating the waveform to the supplier before termination of the surge time interval.