Cathodic Protection of Grounding Grids

2018 ◽  
pp. 248-286
Keyword(s):  
Cathodic Protection ◽  
Galvanic Corrosion ◽  
Steel Corrosion ◽  
Uniform Corrosion ◽  
Grounding System ◽  
Grounding Grid ◽  
Grounding Grids ◽  
Corrosion Pitting ◽  
Impressed Current ◽  
Cathodic Protection System

This chapter contains the corrosion theory of grounding electrodes and basic electrochemistry in corrosion reactions. It contains also the forms of substation grounding grid corrosion (uniform corrosion, pitting corrosion, galvanic corrosion, microbial influenced corrosion), survey on corrosion rate of substation grounding grid, copper and steel corrosion rates, corrosion protection methods (coating, cathodic protection [CP]). The chapter contains also the methods of applying cathodic protection in grounding grids, anode selection, anode spacing, and impressed current in the grounding grid cathodic protection. Finally it contains the required information for design grounding system cathodic protection and sacrificial anode (galvanic) cathodic protection system design steps.

The protection of 500kV substation grounding grids with combined conductive coating and cathodic protection

2015 ◽  
Vol 62 (2) ◽  
pp. 83-87 ◽  
Author(s):  
Zhenxing Ren ◽  
Daowu Yang ◽  
Jun Liu ◽  
Yong Ma ◽  
Zhongtang Huo ◽  
...  
Keyword(s):  
Cathodic Protection ◽  
Monitoring Methods ◽  
Conductive Coatings ◽  
Content Type ◽  
Grounding Grid ◽  
Grounding Grids ◽  
Impressed Current ◽  
Ground Grid ◽  
Impressed Current Cathodic Protection ◽  
Corrosion System

Purpose – The purpose of the paper was to design an anti-corrosion system that combined conductive coatings with cathodic protection for a 500-kV substation ground grid, and provide a basis for the anti-corrosion construction of the installation. Design/methodology/approach – The study took the Shaoguan 500-kV substation grounding grid as the research object. The anti-corrosion performance of KV conductive coatings on grounding metal was researched. In parallel, the alkalinity of substation soil was evaluated according to the German DIN50929 Standard, and the combined protection system comprising conductive coatings and impressed current cathodic protection was designed. Findings – KV conductive coatings, that have resistance to acids, alkalis and salts, can effectively slow down the corrosion rate of the grounding grid. The investigation also provided the outline design, installation, construction requirements and monitoring methods for the 500-kV substation grounding grid. Originality/value – This report contains some guiding significance for anti-corrosion engineering of 500-kV substation grounding grids.

Corrosion Protection Features Of the Hyperion Ocean Outfall★

CORROSION ◽  
1959 ◽  
Vol 15 (7) ◽  
pp. 41-46 ◽  
Author(s):  
HARRY J. KEELING
Keyword(s):  
Los Angeles ◽  
Corrosion Protection ◽  
Cathodic Protection ◽  
Current System ◽  
Coal Tar ◽  
Design Life ◽  
Impressed Current ◽  
Cathodic Protection System ◽  
Negative Buoyancy ◽  
Impressed Current Cathodic Protection

Abstract Details are presented on the planning, design and installation of corrosion protection facilities to provide 100-year design life for a 7-mile, 22-inch steel pipe sewer outfall, the outer end of which is in ocean water 340 feet deep. The outfall serves the sewerage systems of Los Angeles and 16 other adjacent municipalities. An impressed current cathodic protection system is used to protect the exterior of the pipe which is wrapped with a multiple-layer coal tar coating reinforced with glass fiber with bonded impregnated asbestos felt shield. A reinforced pneumatically applied cement mortar jacket provides negative buoyancy. Interior is protected by centrifugally-spun mortar lining with epoxy sleeves at welded tie-in joints. Because of the depth of water in which the pipe was to be placed several novel features were necessary. Cathodic protection was applied continuously during installation by the use of zinc anodes. This system was monitored to detect any serious coating holiday before the pipe was laid in deep water. Permanent test leads also were attached to the pipe so performance of the impressed current system could be checked, continuously. After 1½ years' operation there has been very little change in effective coating resistance, a pipe potential of —1.05 volts versus a copper/copper sulfate electrode being maintained with consumption of about 150 ma. 5.2.3

BARROW ISLAND CATHODIC PROTECTION SYSTEM — DESIGN, INSTALLATION AND COMMISSIONING

1984 ◽  
Vol 24 (1) ◽  
pp. 160
Author(s):  
A. J. Lees
Keyword(s):  
System Design ◽  
Cathodic Protection ◽  
Oil Field ◽  
Protection System ◽  
Detailed Design ◽  
Pilot Scheme ◽  
Repair Costs ◽  
Impressed Current ◽  
Cathodic Protection System ◽  
Impressed Current Cathodic Protection

The Barrow Island oil field, with an area of about one hundred square kilometres containing over six hundred wells, presents an engineering challenge of vast magnitude in the protection of investment in the wells and their casings against the destructive process of corrosion. The growing incidence of casings leaks and escalation in the costs of repairing externally corroded casings provided the impetus for pilot scheme studies and subsequent design and installation of an impressed current cathodic protection system on a scale not previously undertaken in Australia.Data obtained from pilot scheme tests carried out in the latter half of 1979 established the basis of a feasible design. Detailed design and installation through 1980-81 was followed by commissioning of the first area of the system early in 1982.Design of the cathodic protection system was tailored to the local field conditions; the design was modified when necessary as installation and commissioning difficulties arose. Several minor operational problems encountered to date are still to be resolved.The total initial outlay of $5.7 million should result in minimum cumulative savings in well casing repair costs of $15 million over the next 15 years.

An Impressed Current Cathodic Protection System Applied to a Submarine

CORROSION ◽  
1957 ◽  
Vol 13 (2) ◽  
pp. 52-54 ◽  
Author(s):  
E. E. NELSON
Keyword(s):  
Cathodic Protection ◽  
Silver Chloride ◽  
Protection System ◽  
Copper Anode ◽  
Impressed Current ◽  
Silver Silver ◽  
Cathodic Protection System ◽  
The Cost ◽  
Silver Silver Chloride ◽  
Impressed Current Cathodic Protection

Abstract A cathodic protection system using platinum-clad copper anodes on neoprene shields was installed on a fleet-type submarine. Current was supplied from a rectifier to 11 anodes distributed over the hull, the potential being monitored by 13 silver-silver chloride electrodes at selected locations. The system was operated for a ten-month period of active duty after which inspection on a marine railway showed the hull to be in excellent condition with the vinyl paint functioning well. Three of the anodes were damaged but all the cable seals, insulators and anode shields were found intact. The use of platinum-clad anodes of the type employed seems economically feasible since the cost of these anodes constitutes a small part of the cost of installation. Laboratory tests indicate the desirability of replacing the copper anode core by a silver core as an insurance against anode failure in the event of a perforation of the platinum cladding. 5.2.3

scholarly journals Optimization of substation grounding grid design for horizontal and vertical multilayer and uniform soil condition using Simulated Annealing method

PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0256298
Author(s):  
Navinesshani Permal ◽  
Miszaina Osman ◽  
Azrul Mohd Ariffin ◽  
Navaamsini Boopalan ◽  
Mohd Zainal Abidin Ab Kadir
Keyword(s):  
Simulated Annealing ◽  
Soil Structure ◽  
Soil Layer ◽  
Minimum Cost ◽  
Soil Condition ◽  
Problem Formulation ◽  
Soil Conditions ◽  
Grounding System ◽  
Grounding Grid ◽  
Grounding Grids

Grounding systems are critical in safeguarding people and equipment from power system failures. A grounding system’s principal goal is to offer the lowest impedance path for undesired fault current. Optimization of the grounding grid designs is important in satisfying the minimum cost of the grounding system and safeguarding those people who work in the surrounding area of the grounded installations. Currently, there is no systematic guidance or standard for grounding grid designs that include two-layer soil and its effects on grounding grid systems, particularly vertically layered soil. Furthermore, while numerous studies have been conducted on optimization, relatively limited study has been done on the problem of optimizing the grounding grid in two-layer soil, particularly in vertical soil structures. This paper presents the results of optimization for substation grounding systems using the Simulated Annealing (SA) algorithm in different soil conditions which conforms to the safety requirements of the grounding system. Practical features of grounding grids in various soil conditions discussed in this paper (uniform soil, two-layer horizontal soil, and two-layer vertical soil) are considered during problem formulation and solution algorithm. The proposed algorithm’s results show that the number of grid conductors in the X and Y directions (Nx and Ny), as well as vertical rods (Nr), can be optimized from initial numbers of 35% for uniform soil, 57% for horizontal two-layer soil for ρ1> ρ2, and 33% for horizontal two-layer soil for ρ1< ρ2, and 29% for vertical two-layer soil structure. In other words, the proposed technique would be able to utilize square and rectangle-shaped grounding grids with a number of grid conductors and vertical rods to be implemented in uniform, two-layer horizontal and vertical soil structure, depending on the resistivity of the soil layer.

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