METHOD FOR PREDICTIVE DETERMINATION OF A PROCESS VARIABLE

• US 20090248606A1
• Filed: 04/27/2009
• Published: 10/01/2009
• Est. Priority Date: 10/28/2006
• Status: Active Grant

• Current Assignee: ABB Power Grids Switzerland AG (ABB Limited)
• Original Assignee: ABB Technology AG (ABB Limited)
• Inventors: Glock, Jurgen, Heinemann, Lothar
• Granted Patent: US 7,941,393 B2
• Time in Patent Office: Days
• US Class Current: 706/52
• CPC Class Codes: G05B 13/026 using a predictor
• CPC Class Codes: G05B 17/02 electric
• CPC Class Codes: G05B 19/408 characterised by data handling or data format, e.g. reading, buffering or conversion of data
• CPC Class Codes: G05B 2219/31282 Data acquisition, BDE MDE
• CPC Class Codes: G05B 2219/37542 Curve fitting measured points, predict, extrapolate dimension in time
• CPC Class Codes: G05B 23/024 Quantitative history assessment, e.g. mathematical relationships between available data; Functions therefor; Principal component analysis [PCA]; Partial least square [PLS]; Statistical classifiers, e.g. Bayesian networks, linear regression or correlation analysis; Neural networks
• CPC Class Codes: G05B 23/0283 Predictive maintenance, e.g. involving the monitoring of a system and, based on the monitoring results, taking decisions on the maintenance schedule of the monitored system; Estimating remaining useful life [RUL] preventive maintenance, i.e. planning maintenance according to the available resources without monitoring the system G06Q10/06

Abstract

A system and method are disclosed for predictive determination of a process variable (P) in a technical installation. Measured values for the process variable (P) are recorded at predeterminable points in time. Temporally successive recorded measured values are combined to form a weighted measured value. A discrete measured value is assigned to each weighted measured value. A future temporal progression of the process variable (P) is estimated using a linear regression of the discrete measured values, and a point in time in which the process variable (P) reaches a predeterminable limit value is calculated.

Claims

1. A method for predictive determination of a process variable (P) in a technical installation, comprising:

recording measured values for the process variable (P) of the technical installation at predeterminable points in time during operation of the technical installation;

combining temporally successive recorded measured values to form a weighted measured value;

assigning a discrete measured value to each weighted measured value;

estimating a future time profile of the process variable (P) using a regression of the discrete measured values; and

calculating a point in time at which the process variable (P) reaches a predeterminable limit value.

2. The method as claimed in claim 1, wherein the regression is a linear regression.

3. The method as claimed in claim 1, wherein each weighted measured value that lies in a predeterminable tolerance band (H1 . . . H8) is assigned a same discrete measured value.

4. The method as claimed in claim 3, wherein the predeterminable tolerance bands (H1 . . . H8) have different widths.

5. The method as claimed in claim 2, comprising:

calculating a coefficient of determination (B) of the linear regression; and

calculating, with aid of the coefficient of determination (B), a time interval within which the process variable (P) is expected to reach a prescribed limit value.

6. The method as claimed in claim 1, comprising:

taking the measured values into account more or less strongly depending on a point in time of their recording.

7. The method as claimed in claim 6, wherein the measured values taken into account are only measured values lying temporally after a predeterminable point in time.

8. The method as claimed in claim 2, comprising:

detecting damage to the technical installation using the linear regression.

9. The method as claimed in claim 1, comprising:

applying the calculating of a point in time at which the process variable (P) reaches the predeterminable limit value to a gas-insulated switching installation as the technical installation.

10. The method as claimed in claim 9, comprising:

receiving pressure of an insulating gas in a gas space of the gas-insulated switching installation as the process variable (P).

11. The method as claimed in claim 10, wherein the regression is a linear regression.

12. The method as claimed in claim 11, wherein each weighted measured value that lies in a predeterminable tolerance band (H1 . . . H8) is assigned a same discrete measured value.

13. The method as claimed in claim 12, comprising:

calculating a coefficient of determination (B) of the linear regression; and

calculating, with aid of the coefficient of determination (B), a time interval within which the process variable is expected to reach a prescribed limit value.

14. The method as claimed in claim 13, comprising:

taking the measured values into account more or less strongly depending on a point in time of their recording.

15. The method as claimed in claim 14, comprising:

detecting damage to the technical installation using the linear regression.

16. A system for predictive determination of a process variable (P) in a technical installation, comprising:

a sensor;

a database for recording measured values for the process variable (P) of the technical installation at predeterminable points in time during operation of the technical installation; and

a processor for executing a program for;

combining temporally successive recorded measured values to form a weighted measured value;

assigning a discrete measured value to each weighted measured value;

estimating a future time profile of the process variable (P) using a regression of the discrete measured values; and

calculating a point in time at which the process variable (P) reaches a predeterminable limit value.