Analysis Of Corrosion Of Metal Pipeline By AC And DC Current And Design Of Guard Device

With the development of China's economy,the demand for electricity continues to rise.China's territory is vast and its energy distribution is uneven.Fossil energy and natural resources are mainly concentrated in the western region.The consumption of resources and the distribution of population are mainly concentrated in the east.The transportation situation of energy from west to east.There are many forms of energy transportation,including transportation of electric energy,transportation of oil and gas,etc.,which are restricted by land use area and easy to maintain.The “public energy corridor” is gradually formed,but the interaction between energy transmission is also affected.Gradually highlighted.There are two types of transportation for electric energy,one is the traditional AC power network,and the other is high-voltage,UHV DC transmission.Oil and gas energy transportation is mainly transmitted through pipelines.Although the interaction between various systems has been considered at the beginning of construction,as the voltage level of the power grid increases,the radiation capacity increases,and the pipeline radiation increases.The problem of corrosion of pipelines by power transmission cannot be ignored.This paper mainly studies the corrosion mechanism and protection of pipelines for high-voltage DC and AC transmission systems.Control system is built and tested.The purpose is to provide more theoretical support and practical engineering guidance for corrosion protection work in the future.Firstly,the mechanism of the stray current of high-voltage DC grounding electrode to the pipeline corrosion is analyzed.At the same time,the corrosion under AC interference is summarized and expounded,and the current general concern is discussed: in the presence of cathodic protection,The effect of AC and DC interference on pipeline corrosion.The action law of tube ground potential offset and AC interference is discussed.Secondly,the protective measures under the action of direct current and AC and DC were tested,and the protective effects of various protective measures were discussed.The experimental results show that the application of anti-corrosion coating,increased pipeline buried depth,installation of stray current collection net,sacrificial anode cathodic protection and constant voltage source cathodic protection all have certain protective effects on the pipeline,and the application of anti-corrosion coating is obtained.When the anticorrosive coating and the cathodic protection system are applied together,the protection of the pipeline is best.In the experiment,the maximum ground potential is-2.8 V.Based on the analysis of the corrosion mechanism and protective measures of the pipeline,the protection criterion of the DC cathode compensation output current between 0.01 A/m2 and 20 A/m2 is proposed for the experimental platform.A new cathodic protection system is fabricated by AVR MCU.The relevant programs are programmed and the supporting hardware devices are produced.Double control for system of voltage and current is realized.The second-level distributed information management system successfully outputs the voltage and current in the cathodic protection strategy.Through actual experiments,the results show that the new cathodic protection system can reduce the tube ground potential,prevent over-protection under AC interference,and improve pipeline protection.reliability.