Diagnostics on electronic control cards in power plants by analog signature analysis method

The reliability of power plants is dependent on the conditions of the control system. That is true especially for modern power plants which have multiple thousands of electronic cards because they sometimes have sudden trips (shutdowns) caused by malfunction of the electronic control cards in control systems. So, it is very desirable to avoid such trips by predictive maintenance on the control cards before they issue malfunction in operation. Even though the ‘Analog Signature Analysis‘ (ASA) method has been using for more than a decade for predictive maintenance and diagnostics of power plants in Korea, it did not seem to decrease the number of unpredictable trips by faulty control cards for that period. In this paper, the ways how to use ASA test machines and their practical analysis methods for judgment of defect in the parts on the cards were investigated and some sample ICs manufactured from different vendors and manufacturing lots were tested to analyze the difference in Analog Signatures. Through the test results, this paper provides the guidelines for ASA to improve the effectiveness of diagnostics on the electronic control cards.