Study on the interference corrosion of cathodic protection system

2015 ◽  
Vol 33 (5) ◽  
pp. 233-247 ◽  
Author(s):  
Gan Cui ◽  
Zili Li ◽  
Chao Yang ◽  
Xu Wei
Keyword(s):  
Cathodic Protection ◽  
Great Influence ◽  
Simulation Software ◽  
Protection System ◽  
Buried Pipelines ◽  
Stray Current ◽  
Damage Rate ◽  
Soil Conductivity ◽  
Cathodic Protection System ◽  
The Mathematical Model

AbstractDC stray current has a great influence on the corrosion of buried pipelines. In this article, first, we deduce the equation of DC stray current interference on pipeline and determine the corresponding boundary conditions. Second, we discretize the mathematical model with boundary element method. Third, the numerical simulation software BEASY is applied to study the interference corrosion of cathodic protection system. Five types of cathodic protection (CP) interference are considered, namely, anodic, cathodic, combined, induced, and joint interference. Moreover, the effects of different parameters on the degree of the CP interference are investigated. The results show that the degree of interference will decrease with the increase of soil conductivity; smaller coating damage rate will make interference more concentrated; anode parameters have a significant impact on anodic interference but have almost no effect on cathodic interference; for combined, induced, and joint interference, the likelihood for corrosion occurrence will be high at the current outflow point on pipeline.

Recommended Maintenance Practices for Stray Current Corrosion on DC Electrified Systems

2014 ◽  
Author(s):  
Kelvin Zan ◽  
Vish Mawley ◽  
Moises Ramos ◽  
Sarvjit Singh
Keyword(s):  
Los Angeles ◽  
Cathodic Protection ◽  
Communication Systems ◽  
Fire Suppression ◽  
Protection System ◽  
Stray Current ◽  
Voltage Versus ◽  
Right Of Way ◽  
Cathodic Protection System ◽  
Corrective Response

The Los Angeles Metropolitan Transportation Authority (LACMTA), like many other transit agencies throughout the country, is currently addressing the stray current corrosion problems on its rail system. Numerous capital projects have been released by the authority for the rehabilitation of their corroded infrastructures along their right-of-way. In addition, new maintenance procedures have been implemented to minimize corrosion problems to the rail and utility infrastructures located adjacent to the electrified railroad. The corrosion effect on rail infrastructures is often overlooked by most electrified railroad authorities because an immediate corrective response is not necessary for train movement during rail operations. The corrosion process is a natural process that occurs slowly and continuously throughout the life span of all materials, and may be accelerated due to stray currents from the railroad electrification system. Several key locations along the right-of-way have greater impact from stray current corrosion issues: at street crossing due to poor rail insulated boots, switch machines and accumulation of brake dust near passenger platforms. Other significant locations that suffer from stray current effects are overhead and under grade bridges, tunnel structures, rail spikes, fire suppression pipes, sewage pipes and underground feeder cable connections. Moreover, stray current can also cause other vital systems such as signaling systems and communication systems to malfunction. The other aspect of stray current is intentional discharging of stray current into earth ground through Negative Grounding Device (NGD) to maintain negative rail over voltage level for safe operation and reliability of rail service to the public. Typical negative rail voltage with respect to earth ground in operation is over 100VDC which is over the recommended voltage of 50VDC. Corrosion problems can be controlled by the implementation of a cathodic protection system, proper inspection of the running rail, impedance bond connections and proper maintenance of the cathodic protection system and negative grounding devices. The purpose of this paper is to address corrosion issues associated with DC electrified railways, recommend maintenance practices to control stray current sources, recommended maintenance practices for cathodic protection systems and discuss the balancing act to control negative rail over voltage versus intentional discharge of stray current to earth ground.

Operation and maintenance of Impressed Current Cathodic Protection systems on concrete civil structures

2018 ◽  
Author(s):  
Jacob Brink Jansson ◽  
Ruth Sørensen ◽  
Kirsten Riis
Keyword(s):  
Service Life ◽  
Cathodic Protection ◽  
Protection System ◽  
Civil Structures ◽  
Correct Operation ◽  
Operation And Maintenance ◽  
Number Of Factors ◽  
Protection Systems ◽  
Cathodic Protection System

Cathodic protection is a very well-known method of preventing or stopping reinforcement corrosion and thereby extending the service life of reinforced concrete civil structures. However, a number of factors, which among others are design, materials and components, installation methods, quality of workmanship, and operation and maintenance of the cathodic protection system, have influence on the functionality and effectivity of the cathodic protection system. The optimum design that fulfils the Client''s requirements to cost, traffic disruption, service life, etc. shall be determined in accordance with the structure layout and the ability of the Client''s organisation to conduct operation and maintenance. It is critical to ensure that all components are installed properly to achieve the expected service life of the system. Regular and correct operation and maintenance is also crucial to ensure the functionality and effectivity system.

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