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Sensor fault detection using the Mahalanobis distance

Conference · · Transactions of the American Nuclear Society; (United States)
OSTI ID:5799968
;  [1];  [2]
  1. Argonne National Lab., IL (United States)
  2. Los Alamos National Lab., NM (United States)

A method is described by which a localized sensor abnormality can be detected using the Mahalanobis distance. The Mahalanobis distance is approximately the weighted distance from the hyperplane formed by the principal components to the particular observation. Qualitatively, the principal components correspond to the physical laws that govern the behavior of the systems and constraints placed on the system. If there are more sensors than principal components, there are redundant measurements. This redundancy can be used to detect abnormalities that are due either to sensor failure or a localized change in the system being measured. The method compares the distribution of the Mahalanobis distance during normal operation with the distribution during the current operation. A likelihood ratio test is then used to determine if a sensor has gone bad or if operations in the reactor are different from normal. The sensor whose value is not normal is identified by comparing Mahalanobis distances computed with one sensor masked. When the abnormal sensor is masked, the Mahalanobis distance for this subset of sensors will be within prespecified bounds. The method is demonstrated on 20 subassembly output thermocouples in the core of Experimental Breeder Reactor II.

OSTI ID:
5799968
Report Number(s):
CONF-930601--
Journal Information:
Transactions of the American Nuclear Society; (United States), Journal Name: Transactions of the American Nuclear Society; (United States) Vol. 68; ISSN 0003-018X; ISSN TANSAO
Country of Publication:
United States
Language:
English