Development of Cathodic Protection Monitoring Method Using Data Assimilation

Abstract

We have developed inverse analysis method that simultaneously estimates the three-dimensional position of measuring instrument and output current from sacrificial anode. Inverse analysis is a method of estimating an unknown output current from sacrificial anode from potential data measured near the sacrificial anode. In development method, relationship between potential data and state quantities (three-dimensional position and output current from sacrificial anode) to be estimated is defined as state space model. This study can be thought of as generalized state estimation problem that estimates state quantities from measured values and state space model. And, this generalized state estimation problem is solved by Particle Filter. Development method is expected to be able to evaluate output current from sacrificial anode by simple measurement without depending on the movement behavior of measurement instrument. And twin numerical experiment was used to verify the effectiveness of development method. As a result of twin numerical experiment, it was found that both three-dimensional position and output current from sacrificial anode could be estimated with sufficient accuracy. Then, as results of 100 trials of this twin numerical experiment, they were shown that the distribution of estimated values of output current from sacrificial anode was sufficiently small. The above results show effectiveness of development method.