The influence of devices for galvanic separation on the parameters of electrochemical protection of pipelines in the conditions of screening the cathodic current

Issue 24(4) 2019
Pages 20-33

E.V. Isupova, Ukhta State Technical University, Ukhta, Russian Federation

R.V. Aginey, JSC «Giprogazcentr», Nizhny Novgorod, Russian Federation

R.N. Celishhev, Ltd Gazprom transgaz Uhta, Ukhta, Russian Federation

D.S. Savchenko, pipeliner, JSC «Transneft North», Ukhta, Russian Federation


Keywords: protective groundings, device for galvanic separation, the efficiency of electrochemical protection, screening of cathodic current.

http://www.doi.org/10.31615/j.corros.prot.2019.94.4-3

 

The article presents the results of a laboratory study of the operation of devices for galvanic separation of cathodically protected objects and protective ground loops, consisting of semiconductor elements (diodes). During the experiment there were used simulators of protective earthing of point and long type, made of black steel, galvanized steel and copper, as well as prototypes of devices for galvanic separation of systems, made of D305 diodes. An analysis of the research results showed that connecting devices to the breaking of the protective grounding circuit allows bringing the value of the pipe-to-soil potential to the normalized level and reducing the amperage flowing onto the protective ground having an electrical connection to the cathodically-protected structure. For selection parameters of device for galvanic isolation of electrical circuits of anodic and protective groundings, there was proposeda nomogram to determine the necessary type and number of diodes in the device.It seems to be that the introduction of a developed technical device for galvanic separation of electrical circuits of anodic and protective groundings in the practice of anticorrosion protection eliminates the negative influence of protective groundings, minimizes the power consumed by stations, increases the service life of anodic groundings, and also provides the necessary reserve of cathodic protection converters for current and power.