ISO 21857-2021标准规范下载简介
ISO 21857-2021管道系统杂散电流腐蚀的影响防护45-68.pdf简介：
ISO 21857-2021是一个关于管道系统杂散电流腐蚀的影响防护的国际标准，主要用于规范和指导防止和管理由管道系统运行过程中产生的杂散电流对管道材料造成的腐蚀问题。这个标准特别关注的是第45-68部分，其简介可能包括以下内容：
1. 理论背景：这部分可能解释杂散电流腐蚀的原理，即电流离开预定路径，在管道系统周围流动，导致非预期的电化学反应，加剧金属材料的腐蚀。
2. 评估方法：45-68部分可能会涵盖如何评估管道系统对杂散电流的敏感性，包括环境条件、土壤电阻率、管道材质等的影响。
3. 防护策略：根据评估结果，提供了一系列防护措施，如使用防腐层、安装阴极保护系统、优化管道布置等，以减少杂散电流的影响。
4. 应用指南：这部分可能包括实际操作中的步骤和案例分析，帮助用户理解和实施相应的防护措施。
5. 监测与维护：介绍如何定期监控管道系统的腐蚀状况，以及在发现腐蚀迹象时如何进行及时的维护和修复。
6. 持续改进：强调了持续优化管道系统防护措施的重要性，以应对新的环境变化和腐蚀风险。
请注意，以上内容是基于标准的大致框架，并非具体章节内容的详细解读，实际内容应以ISO 21857-2021标准原文为准。
ISO 21857-2021管道系统杂散电流腐蚀的影响防护45-68.pdf部分内容预览：
IS0 21857:2021(E)
IS0 21857:2021(E)
双城中间绿色生态屏障区生态景观道路设计技术导则（试行）.pdflerahighvoltagepowerlinewithoneoverhead
IS021857:2021(E)
IS0 21857:2021(E)
Tidal Effects
Photovoltaicinterferenceonburiedp
DC PhotovoltaicInterferenceresultsfrom conductive coupling
IS021857:2021(E)
Annex H (informative)
Photovoltaic interference
npart of thenormal DCleakageemanatingfromthePhotovoltaic (PV)Systemreturnsto t em'searth viaan interfered system (i.e.buried pipeline)and
H.2SourceofDcleakagecurrents
photovoltaicModules DC cables; inverters
Fora certainvoltagelevel,theDcleakageisdependentontheeffective insulationresistance(Riso)of chesystem.TheeffectiveinsulationresistancecanbemeasuredbeforeconnectingthePvsystemtothe grid[i4l andwill providean indicationof themagnitudeoftheanticipatedleakagecurrentstoground. Thelevel (magnitude)ofDcleakagecurrent isdependentonexternal factorssuchassolarirradiance ambienttemperature,degradedsealantsandmoistureingressatthemodules'level,soilresistivity,etc.
H.2.2Undetected faultconditions
DCleakagecurrentstoground maybe sourced
Faults on the DC sidecan befound inboth grounded and floatingPV systems.The detection mechanisms of these faults depend upon the DC grounding characteristics of the PV system and are inevitably different for grounded and floating configurations[i5]. These faults can remain undetected since the allowable DCfault detection thresholds can be set high,to avoid lost production from false detections or"nuisance"trips from regular and inevitableleakage currents. The undetected DC faults arise as the
IS0 21857:2021(E)
existingdetectionthresholdsforpermissibleDCleakagefromPsystemshavebeenbasedonother issues suchas fireprevention orpersonnel safety.
If the PV system's fault detector/interrupterisblind tohigh impedance faults,theleakage current to ground may exist indefinitely (provided that it is not sufficiently high to cause arcing and fire). The atter implies that thePV array will continueto operate with a permanent reduction inpower output. Briefly,intheevent ofanundetectedground faulttheMPPT (maximumpowerpointtracker) of the nverter will seta new operating pointto a lower powerthanbefore thefault.This is because the MPPT may take thefault as an ordinarypower drop (usuallycaused by changing irradiance)and will shift the operationtoanewoptimalpowerpoint
At the source level:
etecting DC leakagefaults ingrounded PV systems, the UL 1741[16] and the NEC[iZ] require t) llation of a GroundFault Protection Device (GFPD).These devices are designed to interru) lowofDCfaultcurrentsandalsotoalertaboutfaultoccurrences.
IS0 21857:2021(E)
Cleakagetogrounc arising from these cables will be limited
IS0 21857:2021(E)
Modelling the effects of stray current interference on cathodically
L.1 Introduction
Before the modelling process begins it is important to clearly define the purpose of the modelling as wellasthedesiredoutputs.
sired outputs from the model will define what is required by the end user. Usually this is a portwithgraphs,imagesandtablesalongwith descriptivetext.Itcanalso includeelectronic atallowsimplemanipulationandviewingofthemodel.
Detailedinformationofthepipelineisrequired Suchdetailcanincludethefollowing:
Operatingcharacteristics
Outside diameter; 2) Length; 3) Route; 4) Geometry; Date of installation; 6) Design life;
IS021857:2021(E)
IS0 21857:2021(E)
I.3Model specification
odel methodology
A valid methodology is to
break the pipeline down into segments that can be considered as having substantially identical electricalcharacteristics, b)calculatethe impedancefor the segments, taking into account the effect of the coating and soil conditions,and ， resolvethevalues ofthevoltagenodes.
I5Model validation
QX／T 122-2011标准下载IS0 21857:2021(E)
IS0 21857:2021(E)
Assessment ofthe corrosionriskfor steel in concrete orfor
IS021857:2021(E)
TableJ.1 (continued)
TableJ.1 (continued)
AQ／T 2066-2018标准下载IS0 21857:2021(E)