Plant state monitoring method, plant state monitoring computer program, and plant state monitoring apparatus

Abstract

Provided is a plant state monitoring method which monitors an operation state of a plant by using the Mahalanobis distance based on the plant state amount. The method creates a first unit space as a set of data used to be a reference when judging whether the plant operation state during a start operation period is normal according to the state amount in the plant start operation period. The method also creates a second unit space as a set of data used to be a reference when judging whether the plant operation state during a load operation period is normal according to the state amount in the plant load operation period.

1 . A plant state monitoring method of monitoring an operation state of a plant using a Mahalanobis distance related to state quantities of the plant, comprising:
 acquiring state quantities of the plant used to create a third unit space from the plant, the third unit space being a first set of data regarding various kinds of state quantities, and serving as standard for determining whether or not the operation state of the plant is normal;   acquiring a second set of data regarding the various kinds of the state quantities of the plant when the state of the plant is evaluated;   calculating a Mahalanobis distance of the second set of data regarding the various kinds of the state quantities acquired when the state of the plant is evaluated, based on the third unit space; and   determining the state of the plant based on the calculated Mahalanobis distance and a predetermined threshold value,   wherein the third unit space is created based on the state quantities of the plant during a period from the time that is a fifth time before the time when the state of the plant is evaluated to the time that is a sixth time before that time.   
     
     
         2 . The plant state monitoring method according to  claim 2 ,
 wherein a period for which the state quantities of the plant used to create the third unit space are acquired is shifted along with progress of evaluating the state of the plant, and thereby a new unit space is created whenever the plant is evaluated.   
     
     
         3 . The plant state monitoring method according to  claim 1 ,
 wherein the state quantities of the plant, during a period from the time that is a fifth time before the time when the state of the plant is evaluated to the time that is a sixth time before that time, are used to create the unit space, and   the state quantities of the plant, at any time or a plurality of times in one solid day within the period for which the state quantities are collected, are used to create the unit space.   
     
     
         4 . The plant state monitoring method according to  claim 1 ,
 wherein the state quantities used to create the unit space are excluded in chronological order from the creation of the third unit space, such that the oldest one is excluded first.   
     
     
         5 . A plant state monitoring computer program embodied in a tangible medium, executed to cause a computer of a plant state monitoring apparatus, which monitors an operation state of a plant using a Mahalanobis distance related to state quantities of the plant, to perform a plant state monitoring method comprising:
 acquiring state quantities of the plant used to create a third unit space from the plant, the third unit space being a first set of data regarding various kinds of state quantities, and serving as a standard for determining whether or not the operation state of the plant is normal;   acquiring a second set of data regarding the various kinds of the state quantities of the plant when the state of the plant is evaluated;   calculating a Mahalanobis distance which is the set of data regarding the various kinds of the state quantities acquired when the state of the plant is evaluated, based on the third unit space; and   determining the state of the plant based on the calculated Mahalanobis distance and a predetermined threshold value,   wherein the third unit space is created based on the state quantities of the plant during a period from the time that is a fifth time before the time when the state of the plant is evaluated to the time that is a sixth time before that time.   
     
     
         6 . The plant state monitoring computer program according to  claim 5 ,
 wherein a period for which the state quantities of the plant used to create the third unit space are acquired is shifted along with progress of evaluating the state of the plant, and thereby a new unit space is created whenever the plant is evaluated.   
     
     
         7 . A plant state monitoring apparatus for monitoring an operation state of a plant, comprising:
 a unit space creating unit which creates a third unit space based on a various kinds of the state quantities of the plant during a period from the time that is a fifth time before the time when the state of the plant is evaluated to the time that is a sixth time before that time, the third unit space being a first set of data regarding the various kinds of the state quantities, and serving as a standard for determining whether or not the state of the plant is normal;   a Mahalanobis distance calculating unit which calculates a Mahalanobis distance of a second set of data regarding the various kinds of the state quantities acquired when the state of the plant is evaluated, based on the third unit space; and   a plant state determining unit which determines the state of the plant based on the Mahalanobis distance calculated by the Mahalanobis distance calculating unit and a predetermined threshold value obtained from the third unit space created by the unit space creating unit.   
     
     
         8 . The plant state monitoring apparatus according to  claim 7 ,
 wherein a period for which the state quantities of the plant used to create the third unit space are acquired is shifted along with progress of evaluating the state of the plant, and thereby a new unit space is created whenever the plant is evaluated.   
     
     
         9 . The plant state monitoring apparatus according to  claim 7 ,
 wherein the state quantities of the plant, during a period from the time that is a fifth time before the time when the state of the plant is evaluated to the time that is a sixth time before that time, are used to create the unit space, and   the state quantities of the plant, at any time or a plurality of times in one solid day within the period for which the state quantities are collected, are used to create the unit space.   
     
     
         10 . The plant state monitoring apparatus according to  claim 7 ,
 wherein the state quantities used to create the unit space are excluded in chronological order from the creation of the third unit space, such that the oldest one is excluded first.