Case Study on Evaluation of Regional Cathodic Protection Effectiveness and Cathodic Shielding Factors at a Specific Station Site

In practical applications of regional cathodic protection (CP) technology，problems such as excessive CP current demand and cathodic shielding often occur.To address the limitations of evaluating the regional CP system effectiveness at a specific station solely based on 20 detection points，this study integrated field detection and numerical simulation techniques to systematically analyze the CP effectiveness and potential distribution characteristics of pipelines in the station area，proposed pipeline corrosion monitoring and CP system optimization schemes，and revealed the action mechanism of cathodic shielding in regional CP systems.The results showed that:(1) Among the four types of CP optimization schemes，the protection effect of applying impressed current to under-protected hot-spot pipeline sections was the most optimal；(2)Without a grounding system，the shielding effect of parallel pipelines with the same diameter was weak (potential difference ＜5 mV)；(3)When large-diameter and small-diameter pipelines were laid in parallel，large-diameter pipelines exerted cathodic shielding on small-diameter pipelines，leading to a potential difference of 38 mV；(4) When grounding bodies were adjacent to pipelines，the cathodic shielding effect was enhanced；when grounding bodies crossed pipelines，the shielding range expanded to 24 m，and the pipeline potential shifted positively by 400 mV.This research provided a theoretical basis and practical guidance for the design，operation，and maintenance of station-area cathodic protection systems.