Abstract
The results of measurements of telluric currents flowing through pipelines laid in the cryolithozone in Yakutia are presented during geomagnetic storms and lightning discharges occurring in the 10 km zone around the pipeline. The currents reach tens of amperes. Construction of a lightning density distribution map. The effect of a direct current flowing in a 150 m long pipeline with a diameter of 110 mm laid in permafrost on the change in the pipe-to-ground potential is measured. Based on the analysis of variations in the horizontal component of the magnetic activity in the current 24th cycle of solar activity, it is established that the frequency of occurrence of a certain level of the rate of change in geomagnetic activity can be expressed by a power law with an order of magnitude of about two at low values. The exponent decreases to unity as the geomagnetic activity increases. The probability of occurrence of time intervals with given threshold values of the rate of change of geomagnetic activity is determined.
Highlights
If the current goes in the opposite direction, the potential will change to -0.5 V
The data correspond to our results, except for the saturationofthepotentialandthesteepnessofthedependence,whichisdeterminedbythe stateofthelocalsoil.Inourcase,thepipelinesurroundsthefrozenground
It was shown in [6] that for geological auroral electrodes, as the causes of large horizontalcomponentsofmagneticfieldvariations(H)inauroralregions,thegeographical northerncomponent(X)isclearlylargerthantheeastern(Y),butdX/dtanddY/dtare almostequal.Thisisimportantwhenassessingtherisksofoccurrenceofgeomagnetically inducedcurrents(GIT)inthemainobjects,sincethehorizontalgeoelectricfieldcanhave largevaluesinanydirection,andnotonlyparalleltotheelectrode.Animportantparameter for the investigation of the appearance of GIT is the probability of occurrence of large valuesofthetimederivativeofthehorizontalcomponentofthegeomagneticfielddB/dt
Summary
PipelinesinYakutia,forexample,thepipelineEasternSiberia-PacificOcean(ESPO),layat adepthof2m.Inthetransitionalsectionswithdifferentconductivity,thereisadifference inelectricalpotentialsbetweenthepipelineandtheearth,andelectrochemicalcorrosion increases.Theentrypointofwanderingcurrentswillserveasacathode,andthepointof flow ofcurrentswillserveasananode.Localcorrosionofundergroundpipelinesoften manifestsitselfintheform ofulcerspenetratingdeepintothemetal.Studiesonthe determinationofGITgivevaluesuptotensofamperes[1]andhundreds[2].Theinduced currentinthemainobjectscancausesignificantfluctuationsinthepotentialsofthe pipeline-ground(PPG).ChangesinPPGcanreachupto1V[3].Becauseofthechangein thepotential"pipeline-ground"associatedwithtelluriccurrents,thefollowingproblems arise.PositivevaluesofPPG leadtocorrosion.FluctuationsofPPG morethan0.85V. Relative to the natural potential of the metal-ground (-0.66 V) can lead to increased corrosion,eventakingintoaccountthepotentialofprotection0.25V.FluctuationsofPPG upto1.2Vcancausetheproductionofhydrogenattheboundarybetweenthemetaland thecoating,whichwillleadtoaviolationofthebondbetweenthecoatingandthemetal.
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