Device for detecting voltage disturbance

• US 8,024,157 B2
• Filed: 10/27/2008
• Issued: 09/20/2011
• Est. Priority Date: 10/29/2007
• Status: Expired due to Fees

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Xie, Ting, Hu, Fei Huang, Li, Jian Duo, Tang, Guang Qiang, Yu, Yi Gang, Zhuo, Yue
• Primary Examiner(s): Nghiem; Michael P
• Assistant Examiner(s): Ngon; Ricky
• Application Number:
  US12/289,394
• Publication Number:
  US 20090179631A1
• Time in Patent Office: 1,058 Days
• Field of Search: 702 57- 61, 702 64- 71, 702/73, 702/74, 702 80- 82, 702189-193, 702/195, 324/500, 324/512, 324/522, 324/537, 324/76.39, 361/78, 361/79, 361/86, 361/90, 361/91.2
• US Class Current: 702/193
• CPC Class Codes: G01R 19/16547 voltage or current in AC supplies switching for protection H02H; circuits for emergency power supply H02J9/00
• CPC Class Codes: G01R 19/2513 Arrangements for monitoring electric power systems, e.g. power lines or loads; Logging
• CPC Class Codes: H02H 3/50 responsive to the appearance of abnormal wave forms, e.g. ac in dc installations
• CPC Class Codes: H02H 7/26 Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured locating faults in cables G01R31/08

Abstract

At least one embodiment of the present invention provides a method for detecting voltage disturbance. In at least one embodiment the method includes storing the digitized point values of a voltage reference waveform; detecting actual voltage values, and converting the actual voltage values by digitization into point values of the actual voltage which are in one-to-one correspondence with the point values of the reference waveform; comparing the point values of the actual voltage with the corresponding point values of the reference waveform; judging that a voltage disturbance occurs if, for N successive points, the differences between the point values of the actual voltage and the corresponding point values of the reference waveform are all greater than a predetermined disturbance threshold, wherein N is an integer greater than 0. A technical solution of the present invention improves the response speed of the detection, and shortens the response time.

Claims

1. A method for judging occurrence of voltage disturbance, comprising:

storing digitized point values of a voltage reference waveform on a reference waveform storage unit of a device configured to judge an occurrence of a voltage disturbance in electric power measurement equipment;

detecting actual voltage values and converting, in a voltage detection unit of the device, by digitization, actual voltage values into point values of the actual voltage which are in one-to-one correspondence with the stored digitized point values of the reference waveform;

comparing the point values, in a point value comparison unit of the device, of the actual voltage values with the corresponding point values of the reference waveform; and

judging occurrence of a voltage disturbance, in a disturbance judgment unit of the device, if, for N successive points, differences between said point values of the actual voltage and said point values of the reference waveform, obtained from the comparison, are all greater than a disturbance threshold, wherein N is an integer greater than 0, wherein, said reference waveform updating condition is that;

the detected positive peak value of the actual voltage waveform is greater than a positive peak threshold and the negative peak value thereof is smaller than a negative peak threshold, and the differences between the values of the actual voltage and said corresponding point values of the reference waveform are greater than a distortion threshold.

2. The method for judging occurrence of a voltage disturbance as claimed in claim 1, wherein, said point values of the reference waveform are obtained by digitizing a standard voltage waveform successively at a fixed time interval.

3. The method for judging occurrence of a voltage disturbance as claimed in claim 2, wherein, said fixed time interval has a value range of 10 microseconds to 2000 microseconds.

4. The method for judging occurrence of a voltage disturbance as claimed in claim 1, wherein, said disturbance threshold is a product of said point values of the reference waveform and a percentage.

5. The method for judging occurrence of a voltage disturbance as claimed in claim 1;

wherein N ranges from 3 to 5.

6. The method for judging occurrence of a voltage disturbance as claimed in claim 1, further comprising:

updating the point values of the voltage reference waveform according to an updating algorithm when it meets a reference waveform updating condition.

7. The method for judging occurrence of a voltage disturbance as claimed in claim 6, wherein, said updating algorithm is:

R_(m,n)=R_(m-1,n)+[S_(m,n)−

R_(m-1,n)]K 

 

(1)

wherein, R represents the point value of the reference waveform, S represents the point value of the actual voltage, m represents the mth updating and m>

=1, n represents the nth point, and K is an update coefficient for determining an updating speed.

8. The method for judging occurrence of a voltage disturbance as claimed in claim 1, further comprising:

when it is judged that a voltage disturbance occurs, starting to record the point values of the actual voltage until the voltage recovers to normal and continuing for a length of time.

9. The method for judging occurrence of a voltage disturbance as claimed in claim 8, wherein, said length of time is one cycle of the voltage waveform.

10. The method for judging occurrence of a voltage disturbance as claimed in claim 1, further comprising:

storing successively the point values of the actual voltage in a circulating buffer memory according to a first in first out (FIFO) rule, and locking the circulating buffer memory when it is judged that a voltage disturbance has occurred.

11. A non-transitory computer readable medium containing computer instructions stored therein for causing a computer processor to perform the method of claim 1.

12. A method for judging occurrence of voltage disturbance, comprising:

storing digitized point values of a voltage reference waveform on a reference waveform storage unit of a device configured to judge an occurrence of a voltage disturbance in electric power measurement equipment;

detecting actual voltage values and converting, in a voltage detection unit of the device, by digitization, actual voltage values into point values of the actual voltage which are in one-to-one correspondence with the stored digitized point values of the reference waveform;

comparing the point values, in a point value comparison unit of the device, of the actual voltage values with the corresponding point values of the reference waveform; and

judging occurrence of a voltage disturbance, in a disturbance judgment unit of the device, if, for N successive points, differences between said point values of the actual voltage and said point values of the reference waveform, obtained from the comparison, are all greater than a disturbance threshold, wherein N is an integer greater than 0, wherein, said reference waveform updating condition further comprises that;

the differences between the values of the actual voltage and said corresponding point values of the reference waveform are less than or equal to a disturbance threshold.

13. A device for judging occurrence of a voltage disturbance, comprising:

a reference waveform storage unit, to store digitized point values of a reference waveform;

a voltage detection unit, to detect actual voltage values, and to convert by digitization the actual voltage values into point values of the actual voltage which are in one-to-one correspondence with the stored digitized point values of the reference waveform;

a point value comparison unit, to compare the point values of the actual voltage obtained from said voltage detection unit with the corresponding point values of the reference waveform obtained from said reference waveform storage unit; and

a disturbance judgment unit, to obtain comparison results of the point value comparison unit, and to judge occurrence of a voltage disturbance, for N successive points, a differences between the point values of the actual voltage and said corresponding point values of the reference waveform, obtained from the comparison, are all greater than a disturbance threshold, wherein N is an integer greater than 0;

an updating judgment unit, to compare respectively positive and negative peak values of the actual voltage obtained from said voltage detection unit with positive and negative peak value thresholds, comparing comparison results obtained from the point value comparison unit with a distortion threshold, and notifying a reference waveform updating unit to update the point values of the reference waveform when the comparison results meet a reference waveform updating condition; and

the reference waveform updating unit, to update the point values of the reference waveform in the reference waveform storage unit according to an updating algorithm in case that it has been notified to update by the updating judgment unit.

14. The device for judging occurrence of a voltage disturbance as claimed in claim 13, further comprising:

a waveform recording unit, to record the point values of the actual voltage detected by said voltage detection unit when said disturbance judgment unit judges that a voltage disturbance has occurred.

15. The device for judging occurrence of a voltage disturbance as claimed in claim 14, further comprising:

a circulating buffer memory, to successively store the point values of the actual voltage detected by said voltage detection unit according to a first in first out (FIFO) rule, and locking said circulating buffer memory when said disturbance judgment unit judges that a voltage disturbance has occurred.

16. A device for judging occurrence of a voltage disturbance, comprising:

means for storing digitized point values of a voltage reference waveform;

means for detecting actual voltage values and converting, by digitization, the actual voltage values into point values of the actual voltage which are in one-to-one correspondence with the stored digitized point values of the reference waveform;

means for comparing the point values of the actual voltage values with the corresponding point values of the reference waveform; and

means for judging occurrence of a voltage disturbance if, for N successive points, differences between said point values of the actual voltage and said point values of the reference waveform, obtained from the comparison, are all greater than a disturbance threshold, wherein N is an integer greater than 0;

means for comparing respectively positive and negative peak values of the actual voltage obtained from said means for detecting actual voltage values with positive and negative peak value thresholds; and

means for comparing comparison results obtained from the means for comparing point values with a distortion threshold, and notifying a reference waveform updating unit to update the point values of the reference waveform when the comparison results meet a reference waveform updating condition, wherein

the means for storing digitized point values updates the point values of the reference waveform in the reference waveform storage unit according to an updating algorithm in case that it has been notified to update by the updating judgment unit.