Power line waveform measurement system

• US 5,027,285 A
• Filed: 02/28/1989
• Issued: 06/25/1991
• Est. Priority Date: 02/28/1989
• Status: Expired due to Fees

• Current Assignee: ONEAC Corp. (Ametek Incorporated)
• Original Assignee: ONEAC Corp. (Ametek Incorporated)
• Inventors: Elliott, William, McCartney, Andrew, DeWitt, Charles
• Primary Examiner(s): Teska, Kevin J.
• Application Number:
  US07/316,936
• Time in Patent Office: 847 Days
• Field of Search: 364/480, 364/481, 364/483, 364/492, 364/487, 324/103 R, 324/103 P, 324/500, 324/112, 324/102, 340/657, 340/660, 340/661, 340/662, 340/663
• US Class Current: 702/58
• CPC Class Codes: G01D 1/14 giving a distribution function of a value, i.e. number of times the value comes within specified ranges of amplitude
• CPC Class Codes: G01R 13/04 for producing permanent records
• CPC Class Codes: G01R 13/06 Modifications for recording transient disturbances, e.g. by starting or accelerating a recording medium

Abstract

An AC waveform monitoring system includes detecting circuitry for providing a sensed analog signal. Oscillator circuitry is coupled to the detecting circuitry for providing a zero crossing signal. The oscillator circuitry is synchronized with a frequency of the sensed analog signal. Signal processing circuitry is coupled to both the detecting circuitry and the oscillator circuitry for identifying a peak voltage signal and an integral volt-seconds signal of the sensed analog signal responsive to the zero crossing signal. Digital processing circuitry is coupled to the signal processing circuitry and the oscillator circuitry. The digital processing circuitry includes memory for storing a plurality of predetermined signal voltage boundary values and a program utilizing the identified peak voltage signal, the integral volt-seconds signal and the stored predetermined signal values to identify an abnormal voltage event.

Claims

1. An AC waveform monitoring system comprising:

detecting means for providing a sensed analog signal;

oscillator means coupled to said detecting means for generating a zero crossing signal;

said oscillator means including means for synchronizing said zero crossing signal with a frequency of said sensed analog signal and means for generating a control signal representing nonsynchronous operation with said generated zero crossing signal during a power outage;

signal processing means coupled to both said detecting means and said oscillator means for identifying a peak voltage value of said sensed analog signal responsive to said zero crossing signal, said signal processing means including voltage integrating means for identifying an integral volt-seconds value of said sensed analog signal responsive to said zero crossing signal; and

digital processing means coupled to said signal processing means and said oscillator means for receiving said identified peak voltage value and said identified integral volt-second value, said digital processing means including memory means for storing a plurality of predetermined voltage boundary signal values; and

program means utilizing said received peak voltage value, said received integral volt-second value and said stored predetermined signal values responsive to said zero crossing signal for identifying the presence of one of a plurality of predefined abnormal voltage events.

2. An AC waveform monitoring system as recited in claim 1 wherein said digital processing means further is adapted for receiving said generated control signal and wherein said program means replaces said identified integral volt-seconds value with a stored default integral volt-seconds value responsive to said received control signal.

3. An AC waveform monitoring system as recited in claim 1 wherein said program means selectively compares said peak voltage signal and said integral volt-seconds value with a predefined sequence of at least one of said stored predetermined signal values for identifying the presence of one of a plurality of predefined abnormal voltage events.

4. An AC waveform monitoring system as recited in claim 1 wherein said program means provided hysteresis correction of said identified peak voltage value.

5. An AC waveform monitoring system as recited in claim 1 wherein said digital processing means further include means for identifying a time and date value for storing with said identified abnormal voltage event.

6. An AC waveform monitoring system as recited in claim 1 wherein said program means counts successive ones of each identified predefined abnormal event and stores a count value for said predefined abnormal event.

7. An AC waveform monitoring system as recited in claim 1 wherein said digital processing means further include means responsive to said program means for generating a display, said display including said identified abnormal voltage events.

8. An AC waveform monitoring system as recited in claim 1 wherein said digital processing means further include means for identifying a time and date value for storing with each said identified abnormal voltage event and means responsive to said program means for generating a display, said display including said identified abnormal voltage events with said time and date value.

9. An AC waveform monitoring system as recited in claim 8 wherein said program means counts successive ones of each identified predefined abnormal event and storing a count value, and said display including each said identified abnormal voltage event with said time and date value and said count value.

10. An AC waveform monitoring system comprising:

detecting means for providing a sensed analog signal;

oscillator means coupled to said detecting means for generating a zero crossing signal;

said oscillator means including means for synchronizing said zero crossing signal with a frequency of said sensed analog signal and means for generating a control signal representing nonsynchronous operation with said generated zero crossing signal during a power outage;

signal processing means coupled to both said detecting means and said oscillator means for identifying a peak voltage value of said sensed analog signal responsive to said zero crossing signal, said signal processing means including voltage integrating means for identifying an integral volt-seconds value of said sensed analog signal responsive to said zero crossing signal; and

digital processing means coupled to said signal processing means and said oscillator means for receiving said identified peak voltage value and said identified integral volt-second value, said digital processing means including memory means for storing a plurality of predetermined voltage boundary signal values; and

program means for providing hysteresis correction of said identified peak voltage value and utilizing said hysteresis corrected peak voltage value, said identified integral volt-seconds value and said stored predetermined signal values responsive to said zero crossing signal for identifying the presence of one of a plurality of predefined abnormal voltage events.

11. An AC waveform monitoring system as recited in claim 10 wherein said digital processing means further is adapted for receiving said generated control signal and wherein said program means replaces said identified integral volt-seconds value with a stored default integral volt-seconds value responsive to said received control signal.

12. An AC waveform monitoring system as recited in claim 10 wherein said program means selectively compare said peak voltage signal and said integral volt-seconds value with a predefined sequence of at least one of said stored predetermined signal values for identifying the presence of one of a plurality of predefined abnormal voltage events.

13. An AC waveform monitoring system as recited in claim 10 wherein said digital processing means further include means responsive to said program means for identifying a time and date value for storing with said identified abnormal voltage event.

14. An AC waveform monitoring system as recited in claim 10 wherein said digital processing means further include means responsive to said program means for generating a display, said display including said identified abnormal voltage events.

15. An AC waveform monitoring system as recited in claim 10 wherein said digital processing means further include means responsive to said program means for identifying a time and date value for storing with said identified abnormal voltage event and means responsive to said program means for generating a display, said display including said identified abnormal voltage events with said time and date value.

16. An AC waveform monitoring system as recited in claim 10 wherein said digital processing means further include means responsive to said program means for identifying a time and date value for storing with said identified abnormal voltage event, means identifying a count value corresponding to successively identified ones of one predefined abnormal event, and means responsive to said program means for generating a display, said display including said identified abnormal voltage events with said time and date value and said count value.

17. An AC waveform monitoring system comprising:

detecting means for providing a sensed analog signal;

oscillator means coupled to said detecting means for generating a zero crossing signal;

said oscillator means including means for synchronizing said zero crossing signal with a frequency of said sensed analog signal and means for generating a control signal representing nonsynchronous operation with said generated zero crossing signal during a power outage;

signal processing means coupled to both said detecting means and said oscillator means for identifying a peak voltage value of said sensed analog signal responsive to said zero crossing signal;

said signal processing means including voltage integrating means for identifying an integral volt-seconds value of said sensed analog signal responsive to said zero crossing signal; and

digital processing means coupled to said signal processing means and said oscillator means for receiving said identified peak voltage value and said identified integral volt-second value, said digital processing means including memory means for storing a plurality of predetermined voltage boundary signal values;

program means utilizing said identified peak voltage value, said identified integral volt-seconds value and said stored predetermined signal values responsive to said zero crossing signal for identifying the presence of one of a plurality of predefined abnormal voltage events;

means for identifying a time and date value for storing with said identified abnormal voltage event and means responsive to said program mean for generating a display, said display including said identified abnormal voltage events with said real time and date value.