Evaluation of Stray Current Effect on the Cathodic Protection of Underground Pipeline

1996 ◽  
Author(s):  
K. W. Park ◽  
Y. B. Cho ◽  
K. S. Jeon ◽  
S. M. Lee ◽  
Y. T. Kho
Keyword(s):  
Cathodic Protection ◽  
Drainage System ◽  
High Standard ◽  
Considerable Effect ◽  
Mean Value ◽  
Distribution Analysis ◽  
Underground Pipeline ◽  
Stray Current ◽  
Transit System ◽  
Potential Measurement

Two types of stray current which affect the cathodic protection of underground pipeline are discussed. One is the stray current by DC transit system and the other is that originated from the nearby cathodic protection system. The popular evaluation methods of the pipe-to-siol potential measurement was undertaken to evaluate the corrosion activity of pipeline. In case when the pipe was affected by the stray current, the measured pipe-to soil potential was significantly deviated from the mean value resulting in normal distribution. Analysis of such distribution pattern has revealed that the pipe under investigation was in the condition of insufficient protection (noble mean potential and high asymmetry coefficient) due to the considerable effect of stray current (high standard deviation value). It was also confirmed that the efficiency of drainage system was so low (<10%) due to the improper selection of drainage point. Simultaneous measurement of the magnitude and direction of the sheath current resulted in information about the place where stray current entered into pipe and escaped to soil. For the second case of stray current problem, it is shown that it has been caused by the combined interference from nearby CP system.

Rail-to-Earth Resistance Assessment for a Medium Capacity Transit System With Continuous Negative Rails by Potential Measurement

2016 ◽  
Author(s):  
Bih-Yuan Ku ◽  
Ching Liang Wu ◽  
Chun-Fu Lin
Keyword(s):  
Unit Length ◽  
Point Of View ◽  
Voltage Sag ◽  
Rapid Transit ◽  
Transit System ◽  
Potential Measurement ◽  
Qualitative And Quantitative ◽  
Ground Resistance ◽  
Traction Current ◽  
Resistance Assessment

This paper presents the development of a qualitative and quantitative assessment of the resistance to ground for the electrically continuous negative rails of a medium capacity transit line of the Taipei Rapid Transit System. Using synchronous potential measurements at three stations we examine potential profiles to locate potential rail sections with low resistance to ground qualitatively. Also the voltage sag values are used to quantitatively calculate rail-to-ground resistance per unit length. The approach presented in this paper requires only voltage measurements with the traction current as the energization source. Thus, this approach can be performed as a routine maintenance procedure to obtain rail-to-ground resistance values from a system-wide point of view.

An Array of Multielectrodes for Locating, Visualizing, and Quantifying Stray Current Corrosion

CORROSION ◽  
10.5006/2828 ◽  
2018 ◽  
Vol 74 (10) ◽  
pp. 1093-1101 ◽  
Author(s):  
Ke Wang ◽  
Facundo Bob Varela ◽  
Mike Yongjun Tan
Keyword(s):  
Cathodic Protection ◽  
Laboratory Simulation ◽  
Buried Pipeline ◽  
Stray Current ◽  
Simulation Experiments ◽  
Corrosion Rates ◽  
Pipeline Corrosion ◽  
Probe Array

An array of multielectrode corrosion probes, designed based on a series of coupled wire beam electrodes (WBEs), has been devised as a new tool for locating, visualizing, and quantifying the effects of stray currents on buried pipeline corrosion. It has been demonstrated in laboratory simulation experiments that this WBE probe array is capable of detecting stray current corrosion affected sites along a pipeline, visualizing stray current corrosion patterns and corrosion rates, and evaluating the efficiency of cathodic protection against stray current corrosion. Based on these results, two applications of this WBE probe array have been proposed for stray current corrosion survey and monitoring.

scholarly journals Digital Terrain Characterization of Nilona Micro Watershed of Darwha Block of Maharastra

2021 ◽  
pp. 42-50
Author(s):  
R. Rakesh ◽  
Ashay D Souza ◽  
Sudipta Chattaraj
Keyword(s):  
Quantitative Description ◽  
Drainage System ◽  
Digital Terrain Model ◽  
Mean Value ◽  
Terrain Analysis ◽  
Terrain Model ◽  
Terrain Attributes ◽  
Digital Terrain ◽  
Grid Points

Watershed characterization is the first step in the sustainable management of    watershed resources. Morphometric analysis of a watershed using Digital Elevation Model (DEM) provides a quantitative description of the drainage system which is an important aspect   of the characterization of watersheds. The study was conducted in Nilona micro-watershed covering an area of 1297.35 ha in Darwha tehsil of Yavatmal district, Maharashtra. The terrain attributes and drainage configuration were derived from the Cartosat-1 data, 10m resolution Digital Terrain Model (DTM) using ArcGIS. Surface soil samples of 118 locations were collected from grid points located at regular interval of 325 m. The digital terrain analysis  showed that slope varies from 0 to 45.9 percent, with a mean value of 4.5%. Most of the area of Nilona micro-watershed was classified as gentle sloping. Profile curvature   varies from -5.1 to 4.6 m m-1, respectively indicating the coexistence of erosive as well  as depositional landforms. Overall, the study documents the utility of   site-specific modeling and geo-statistical interpolation based predictive mapping for watershed planning.

Integrity Challenges Associated with Stray Current Corrosion Across Monolithic IJ's and Resolutions

2021 ◽  
Author(s):  
Ebrahim Salem Al Salemi ◽  
Saleh Salem Al Ameri ◽  
Ajiv Mohan Nair ◽  
Humaid Musabah Al Ali ◽  
Mario Jr Javier Zantua ◽  
...  
Keyword(s):  
Cathodic Protection ◽  
Ionic Current ◽  
Low Carbon Steel ◽  
Internal Surface ◽  
Low Carbon ◽  
Stray Current ◽  
Gas Industry ◽  
Factors Affecting ◽  
Steel Material ◽  
Internal Lining

Abstract Corrosion and subsequent failures is one of the main factors affecting uninterrupted operations of Oil & Gas Industries. Pipelines are considered as most convenient means of crude and gas transportation in Oil & Gas Industry. Buried pipelines generally made of low carbon steel material are protected externally by coating and applying impressed current cathodic protection (ICCP). Monitoring and maintaining adequate level of Cathodic Protection (CP) for such pipelines remains challenging for corrosion engineers due to increased level of field congestion, complexity in accurate current mapping and mitigation of corrosion phenomena. Failure of pipelines due to corrosion can be catastrophic with following consequences: Loss of containment fluid and thereby probable fatalityDamage to asset/company reputationSafety and Environment (Fire, Toxic gases and Oil Spill)Resource and downtime cost impact Isolation joints IJ's are designed with very high insulating material at mating areas and installed on pipelines by welding to avoid loss of Cathodic Protection (CP) current. Due to high electrical insulation, a potential difference is formed across of IJ's due to applied CP current and stray currents. In upstream Oil & Gas Industry, multiphase crude transported via pipeline will have certain percentage of water and will induce an internal conductive path across the IJs resulting in ionic current discharge at anodic areas within internal surface. This study focuses on factors contributing to such internal stray current corrosion, limitation in monitoring methodology and mitigation programs. The study concludes with recommendations such as design modifications, improvement in internal lining properties and improved installation guidelines. The study practically illustrates effectiveness of combined resistive bonding and zinc earthing cells installation for controlling stray current propagation in order to reduce the corrosion rate so as to maintain Integrity of pipelines.

COST CALCULATION IN PREFABRICATED TIMBER CONSTRUCTION: METHODOLOGY OF ASSESSMENT AND GENERAL REQUIREMENTS

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
Dieter Schlagbauer ◽  
Joerg Koppelhuber ◽  
Detlef Heck
Keyword(s):  
Mean Value ◽  
General Level ◽  
Cost Calculation ◽  
Observation Data ◽  
Distribution Analysis ◽  
Construction Operations ◽  
Cost Calculations ◽  
The Individual ◽  
High Level ◽  
Cost Parameters

Cost calculations within the construction industry can be performed at various levels of detail. Starting at a very general level using component-dependent cost parameters (eg: cost per cubic meter of gross volume [€/m]) the calculation can be done in the most detailed method by evaluation the individual cost components (material, equipment and labor) separately for every single task. For the traditional construction operations like masonry or concreting works a lot of information is provided to determine the performance values within a close range. For the field of cross laminated timber (CLT) constructions these substantially basics are not well established yet. The actual calculations are often based on in-house knowledge of timber companies without cross company references. To enhance the calculation basics a modified REFA analysis method (REFA 1984, Schlagbauer, Heck and Hofmann 2011) was conducted to collect on site observation data. The results of the task distribution analysis showed very similar results compared to other construction works on the level activities and interruptions with a mean value of approximately 75 % activities. But at a closer look greater deviations were found as main CLT-tasks have a value of 59% compared to masonry work (38%) or concreting work (51%). This bigger share of main activities within CLT works can especially explained by the high level of prefabrication work but has to be considered within the calculation.

scholarly journals Experimental Study on the Influence of AC Stray Current on the Cathodic Protection of Buried Pipe

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Qingmiao Ding ◽  
Yueming Fan
Keyword(s):  
Experimental Study ◽  
Cathodic Protection ◽  
Comprehensive Analysis ◽  
Stray Current ◽  
Buried Pipe ◽  
Ir Drop ◽  
Threshold Length ◽  
Protection Potential ◽  
Ground Potential ◽  
Coating Crack

The size of the damaged area of the coating and its position on the pipeline impacted the cathodic protection potential, and there was a damaged area of the greatest impact value. When damaged area was 300 mm2, the IR drop was the largest, and this situation could easily lead to inadequate protection; when the parallel spacing between pipeline and interference source was unchanged, the measured value curves of cathodic protection potential presented “U” shaped trend with the increasing stray current interference intensity. Under certain parallel spacing between pipeline and interference source, high alternating stray current intensity would cause serious negative offsets, so that the overprotection of the pipeline occurred, and make the coating crack; there was a parallel threshold length. When less than the threshold, the pipe-ground potential increases rapidly with the parallel length increasing. In order to judge whether a pipeline was interference by AC stray current and the risk of stray current corrosion, we should make a comprehensive analysis of the cathodic protection energizing potential, the switch-off potential, AC pipe-soil potential, IR drops, and so on.

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