CATHODIC CORROSION PROTECTION SYSTEM AND CATHODIC CORROSION PROTECTION METHOD FOR UNDERGROUND PIPELINE

摘要

PROBLEM TO BE SOLVED: To provide a method for reducing the risk of corrosion of both pipelines without inducing the over corrosion protection and the direct current interference risk of other underground pipelines by using a cathodic corrosion protection current of another side cathodic corrosion protection pipeline when one side pipeline connected through an insulating joint is not protected from corrosion or low in the corrosion protection level.;SOLUTION: A cathodic corrosion protection system is provided with: a cathodic corrosion protection current generation means 2 connected to a cathodic corrosion protection line being one side underground pipeline connected through an insulating joint 1 and capable of performing a constant current control to the generation of a cathodic corrosion protection current; a pipe-to-earth potential measuring means 3 capable of measuring respective pipe-to-earth potentials at the both sides of the insulating pipe 1; and an insulating joint protection means 4 which is connected to the both underground pipelines and in which at least diodes connected in reverse parallel are connected in parallel to the insulating joint 1. In the cathodic corrosion protection system, the generation current of the cathodic corrosion protection current generation means 2 is controlled so that the difference between the pipe-to-earth potentials at the both sides of the insulating joint 1, measured by the pipe-to-earth potential measuring means 3, becomes the operation potential of the diodes.;COPYRIGHT: (C)2010,JPO&INPIT