750kV High-voltage AC Transmission Lines On Buried Pipelines Disturbance Study

In the recent years, there has been a trend to run metallic pipelines carrying petroleumproducts and high voltage AC power lines parallel to each other in a relatively narrow strip ofland. Due to this sharing of the right-of-way, overhead AC power line electric field mayinduce voltages on the metallic pipelines running in close vicinity leading to adverse effects.In the case of steady-state interference，If the induced voltage on the pipeline exceeds acertain value not only threat to personal safety，causing the corrosion of AC interference, andeven lead to the operation of the cathodic protection system abnormal. In fault interferencecircumstances, it is possible to instant excitation three-dimensional kV high pressure,resulting in anti-corrosion layer breakdown，a serious danger to employees personal safety.How to protect，avoid stray current corrosion of the pipeline，as well as protect the pipeline,and the corresponding work with the surrounding civilian facilities security has becomeincreasingly concerned about the problem. This paper reports on the main research andanalysis from the following aspects:(1) To use CDEGS software simulation to calculate the impact law of different factors onthe pipeline, and take advantage of the indoor test to verify. Anti-corrosion layer resistivityranging from0.1kΩ m2to1kΩ m2, and the steady-state current of transmission line affectsthe induced voltage and the maximum longitudinal current greatly. With the increase of theparallel distance and the decrease of space distance and decrease of Intersection angle, theinterference increase dramatically, then change moderately. The soil resistivity, height of theline and the depth, diameter and wall thickness of the pipe have little influence to the inducedvoltage.(2) Based on various influencing parameters affect the status of the pipeline，simulationof the extreme value of various factors while the pipeline in a safety condition, getting theminimum parallel spacing and the maximum length of parallel. The higher conductor heightand the smaller soil resistivity, the smaller of the pipe and the high tension line paralleldistance. The influence of soil resistivity is much greater than the height of the line to pipelineinduced voltage. (3) To use CDEGS software simulation of the interference of various factors on thepipeline in the state of the lightning tower. With the increase of distance between pipelineinduced voltage sharply reduced first and then changes gently; Pipes are interferenceincreases with the increase of soil resistivity; Proportional to the lightning current amplitudes;Induced voltage in the parallel length is small pipe increased peak amplitude is small, alongwith the increase of the length of the parallel induction voltage peak increase approximation isproportional; With the increase of the crossover point of pipeline reduce the interference.(4) Field testing and getting pipe by the static interference current and dynamicinterference current and the pipe communication potential, analysis of pipes degree ofinterference; According to site investigation the income distribution relations of high-voltagetransmission lines and pipelines, pipe will be in accordance with different resistivity dividedinto regions, each segmented region, said a part of a span to establish model to simulatecalculation pipeline under high-line condition, for this paper.