Abstract Cathodic protection (CP) method is widely used in the oil and gas industry in order to prevent (or reduce) rust and corrosion of structures and metal pipelines or their associated cost. To guarantee a more effective CP system, an applicable design for the under protected structures is required. The conventional models recommended by the designers are based on the equivalent circuit of the overall CP system, which are lumped model and may be useful for the compact systems like integrated industrial plants, where oil and gas pipelines are installed in kilometers. Since such a lumped model leads to inaccurate results, this study aims at proposing a new distributed model to design a cathodic protection system for oil and gas transmission pipelines, which is extendable and can be useable in other structures. The main difference between the proposed model and the conventional approach is the use of actual measured soil resistance throughout the structure instead of using a fixed mean value. The effectiveness of the proposed model has been demonstrated by analytical analysis and computer-based simulations. The proposed method shows a significant superiority over the conventional lumped models when variation of the soil resistance through the structure is high. Hence, the application of the devised method in design of a CP system of the pipelines improves the quality of the protection. The distributed equivalent circuit model with its distributed parameters is utilized to design and analyze the performance of a real case i.e., the CP protection system of a 20-km transmission pipeline with soil-measured data. To calculate the performance of the designed CP system, the results are compared with those of the conventional model.

中文翻译：

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油气管道阴极保护系统的设计与分析，采用分布式等效电路模型

摘要 阴极保护（CP）方法广泛应用于石油和天然气行业，以防止（或减少）结构和金属管道的生锈和腐蚀或其相关成本。为了保证更有效的 CP 系统，需要对受保护结构进行适用的设计。设计人员推荐的常规模型是基于整个CP系统的等效电路，是集总模型，可能适用于集成工业工厂等紧凑型系统，其中石油和天然气管道以公里为单位安装。由于这种集总模型会导致结果不准确，本研究旨在提出一种新的分布式模型来设计油气输送管道的阴极保护系统，该系统可扩展且可用于其他结构。所提出的模型与传统方法之间的主要区别是在整个结构中使用实际测量的土壤阻力，而不是使用固定的平均值。分析分析和基于计算机的模拟已经证明了所提出模型的有效性。当通过结构的土壤阻力变化很大时，所提出的方法显示出优于传统集总模型的显着优势。因此，将所设计的方法应用于管道CP系统设计中，提高了保护质量。利用带分布参数的分布等效电路模型，利用土壤实测数据对20km输电管道CP保护系统实际案例进行了性能设计和性能分析。