| 摘要 |
PROBLEM TO BE SOLVED: To suppress effects of depolarization due to off time as much as possible and obtain measurements with high accuracy, in measuring a coupon instant off potential (E), together with a coupon DC current density (I), a coupon AC current density (I), a coupon potential (E), etc. in the same time zone.SOLUTION: A measurement time consisting of a plurality of unit measurement times combined continuously as a simultaneous time zone is set, and a coupon current density of a current flowing in a coupon connected to a buried pipeline is measured in a unit measurement time. A coupon instant off potential to be measured with the connection between the buried pipeline and the coupon turned off is measured, and measurement of the coupon instant off potential is started a set time after the connection between the buried pipeline and the coupon is turned off. The connection between the pipeline and the coupon is turned on immediately after the coupon instant off potential is measured only in a measurement time of one cycle of AC influencing the buried pipeline, and the measurement of the coupon current density is started at a time interval after turning 'on'. |
