GB/T 21246-2007 埋地钢质管道阴极保护参数测量方法

ICS75.180.30

E98

中华人民共和国国家标准

GB/T21246-2007

埋地钢质管道阴极保护

参数测量方法

Measurementmethodforcathodicprotectionelectric

parametersofburiedsteelpipelines

2008-发布2008-实施

国家质量监督检验检疫总局发布

GB/T21246—2007

目次

前言…………………………Ⅲ

1范围······················································································································································１

2规范性引用文件··································································································································１

3术语和定义··········································································································································１

4基本规定··············································································································································３

4.1测量仪表··········································································································································３

4.2电压、电流仪表······························································································································３

4.3参比电极··········································································································································４

4.4测量基本要求··································································································································４

4.5电位极性··········································································································································５

5电位测量··············································································································································６

5.1自然电位··········································································································································６

5.2通电电位··········································································································································６

5.3断电电位··········································································································································６

5.4密间隔电位······································································································································７

5.5消除IR降电位··································································································································８

5.6阴极极化电位偏移······················································································································１０

5.7牺牲阳极开路电位······················································································································１２

5.8牺牲阳极闭路电位······················································································································１２

5.9极化探头法··································································································································１３

5.10管道阳极区定位························································································································１４

6牺牲阳极输出电流测量···················································································································１５

6.1标准电阻法··································································································································１５

6.2直测法··········································································································································１６

7管内电流测量··································································································································１６

7.1电压降法······································································································································１６

7.2标定法··········································································································································１７

8管道外防腐层电阻率测量···············································································································１９

8.1适用性··········································································································································１９

8.2方法介绍······································································································································１９

8.3测量基本要求······························································································································１９

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8.4测量步骤······································································································································１９

8.5数据处理······································································································································２０

9绝缘接头（法兰）绝缘性能测量···································································································２１

9.1兆欧表法······································································································································２１

9.2电位法··········································································································································２２

9.3漏电电阻法··································································································································２３

9.4PCM漏电率测量法························································································································２４

9.5接地电阻测量仪法······················································································································２５

10接地电阻测试································································································································２６

10.1长接地体接地电阻测试·············································································································２６

10.2短接地电阻测试························································································································２８

11土壤电阻率测量····························································································································２８

11.1等距法········································································································································２８

11.2不等距法····································································································································２９

12管道外防腐层地面检漏测量·········································································································３０

12.1交流电流衰减法························································································································３０

12.2交流地电位梯度法（ACVG）·····································································································３１

12.3直流地电位梯度法（DCVG）·····································································································３２

12.4音频检漏法································································································································３４

附录A（资料性附录）条文说明···········································································································３５

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前言

本标准是在总结原行业标准SY/T0023-97实施8年来的实践经验，吸收了国外标准NACETM0497

《埋地或水下金属管道系统阴极保护准则的测量技术》、NACETM0102《埋地管线保护涂层电导测量

技术》、NACERP0502《管道外腐蚀直接评估方法》、DIN30676《外表面阴极保护的设计和应用》和

ISO15589-1《管道输送系统的阴极保护》（第一部分：陆上管道）中相应测量方法的主要内容的基础

上，结合现阶段国内在测量手段和管道建设方面出现的新需求编制而成。

本标准自发布之日起，《埋地钢质管道阴极保护参数测试方法》（SY/T0023-97）废止。

本标准的附录A为资料性附录。

本标准由中国石油天然气集团公司提出。

本标准由石油工程建设专业标准化委员会归口。

本标准主编单位：中国石油集团工程设计有限责任公司西南分公司（四川石油勘察设计研究院）。

本标准参编单位：中国石油天然气管道有限公司、西南油气田分公司输气管理处。

本标准主要起草人：

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埋地钢质管道阴极保护参数测量方法

1范围

本标准规定了埋地钢质管道阴极保护参数的现场测量方法，本标准所列方法应根据相关标准的

规定和使用者的要求选用。

本标准适用于埋地钢质管道阴极保护参数的现场测量。钢质储罐外底板、滩海钢质管道和结构

的阴极保护参数测量可参照采用。

2规范性引用文件

下列文件中的条款通过本标准的引用而成为本标准的条款。凡是注日期的引用文件，其随后所

有的修改单（不包括勘误的内容）或修订版均不适用于本标准，然而，鼓励根据本标准达成协议的

各方研究是否可使用这些文件的最新版本。凡是不注日期的引用文件，其最新版本适用于本标准。

JJG123直流电位差计检定规程

JJG124电流表、电压表、功率表及电阻表检定规程

JJG315直流数字电压表检定规程

JJG366接地电阻表检定规程

JJG598直流数字电流表检定规程

JJG622绝缘电阻表（兆欧表）检定规程

3术语和定义

下列术语和定义适用于本标准。

3.1

管地电位thepipe-to-soilpotential

管道与其相邻土壤的电位差。

3.2

通电电位onpotential

阴极保护系统持续运行时测量的构筑物对电解质电位。

3.3

IR降IRdrop

根据欧姆定律，由于电流的流动在参比电极与金属管道之间电解质内产生的电压降。

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3.4

断电电位offpotential

瞬间断电电位instant-offpotential

断电瞬间测得的构筑物对电解质电位。

注：通常情况下，应在切断阴极保护电流后和极化电位尚未衰减前立刻测量。

3.5

冲击电压voltagespiking

阴极保护电流被中断或施加的瞬间，由过渡过程引起的管道上的瞬间性电位波动。

3.6

密间隔电位测量（CIPS）close-intervalpotentialsurvey

一种沿着管顶地表，以密间隔（1~3m）移动参比电极测量管地电位的方法。

3.7

电位准确测量技术intensivemeasurementtechnique

同时测量管地电位与垂直方向土壤电位梯度的技术。

注：通过电位准确测量技术可识别防腐层缺陷，并能够计算出缺陷处的消除IR降电位。

3.8

平衡电流equalisingcurrent

平衡电流也称“二次电流”，是指中断保护电流后，在构筑物的极化差异部位之间流动的电流，

平衡电流可能是测量消除IR降电位的误差源。

3.9

远参比法referenceelectrodemethodremotefrompipeline

将参比电极置放于距被测管道较远（地电位趋于零）的地面测量管地电位的方法。

3.10

远方大地remoteearth

在该区域内任何两点之间没有因电流流动引起的可测量的电压降。

3.11

防腐层电阻率coatingresistivity

防腐层电阻率是防腐层电阻和防腐层表面积的乘积。

3.12

防腐层电阻coatingresistance

防腐层电阻是涂敷有防腐层的金属构筑物和电解质（土壤）之间的电阻。

注：防腐层电阻主要是由防腐层上的缺陷的数量和大小来确定的，因此，它是衡量防腐层质量的标准。

3.13

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交流电流衰减法alternatingcurrentattenuationsurvey

一种在现场应用电磁感应原理，采用专用仪器测量管内信号电流产生的电磁辐射，通过测量出

的信号电流衰减变化，来评价管道防腐层总体情况的地表测量方法。收集到的数据可能包括管道埋

深、位置、异常位置和异常类型。

3.14

交流地电位梯度法（ACVG）alternatingcurrentvoltagegradientsurvey

一种通过测量沿着管道或管道两侧的由防腐层破损点漏泄的交流电流在地表所产生的地电位梯

度变化，来确定防腐层缺陷位置的地表测量方法。

3.15

直流地电位梯度法（DCVG）directcurrentvoltagegradientsurvey

一种通过测量沿着管道或管道两侧的由防腐层破损点漏泄的直流电流在地表所产生的地电位梯

度变化，来确定防腐层缺陷位置、大小，以及表征腐蚀活性的地表测量方法。

3.16

腐蚀活性点corrosionactivity

腐蚀正在进行，并以一定速率发展的部位，该发展速率足以导致管道在使用期内承压能力降低

甚至穿孔。

4基本规定

4.1测量仪表

4.1.1测量仪表必须具有满足测试要求的显示速度、准确度和量程，同时还应具有携带方便、供电

方便、适应现场测量环境的特点。对所用的测量仪表，必须按国家现行标准的有关规定进行定期校

验。

4.1.2为了提高测量的准确度，宜优先选用数字式仪表。

4.2电压、电流仪表

4.2.1直流电压表选用原则：

a)数字式电压表的输入阻抗应不小于10MΩ；指针式电压表的内阻应不小于100kΩ/V。

b)电压表的分辨率应满足被测电压值的精度要求，至少应具有三位有效数。

c)数字式电压表的准确度应不低于0.5级；指针式电压表的准确度应不低于2.5级。

d)测量受交流干扰的管道的管地电位时，应选用对工频干扰电压具有足够滤除能力的数字式

直流电压表，确保直流电位的显示值中叠加的交流干扰电压值不超过5mV，或选用指针式

电压表。

4.2.2直流电流表选用原则：

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a)电流表的内阻应小于被测电流回路总电阻的5%。

b)电流表的分辨率应满足被测电流值的精度要求，至少应具有两位有效数，当只有两位有效

数时，首位必须大于1。

c)电流表的准确度应不低于2.5级。

4.3参比电极

4.3.1在进行管地电位测量时，通常情况下，应采用铜-饱和硫酸铜电极（以下简称硫酸铜电极，

代号CSE）作为参比电极。其制作材料和使用必须满足下列要求：

a)铜电极采用紫铜丝或棒（纯度不小于99.7%）。

b)硫酸铜为化学纯，用蒸馏水或纯净水配制饱和硫酸铜溶液。

c)渗透膜采用渗透率高的微孔材料，外壳应使用绝缘材料。

2

d)流过硫酸铜电极的允许电流密度不大于5µA/cm。

4.3.2硫酸铜电极相对于标准氢电极的电位为+320mV（20℃），其电极电位误差应不大于5mV。

4.3.3对不宜使用硫酸铜电极的环境，可采用高纯锌参比电极（纯度不小于99.995%）替代，相对

硫酸铜电极的-850mV电位的换算关系如下（25℃）:

采用75%石膏、20%膨润土、5%硫酸钠回填料包覆的高纯锌参比电极：+250mV。

4.4测量基本要求

4.4.1本标准应在受过阴极保护专业知识培训，并具有相关实践经验的人员指导下使用。

4.4.2所有测量连接点应保证电接触良好。

4.4.3测量导线应采用铜芯绝缘软线；在有电磁干扰的地区（如高压输电线附近），应采用屏蔽导

线。

4.4.4测量仪表应按使用说明书的有关规定操作。

4.4.5安全守则

a)在对强制电流阴极保护电源设备进行安装、调试、测量、维修之前，有关人员应该受过电

气安全培训，并掌握相关电气安全知识。

b)测量接线应采用绝缘线夹和插头，以避免与未知高压电接触，测量操作中应首先接好仪表

回路，然后再连接被测体，测量结束时，按相反的顺序操作，并执行单手操作法。

c)在对电隔离设施进行测量之前，应检查是否存在危险电压。

d)在雷暴天气下，应避免测试。

e)当测量导线穿越街道、公路等交通繁忙的地段时，应设置安全警示标志或站立安全监护人

员。

f)在涵洞或隧道中测试时，应首先检查涵洞或隧道的结构安全性及对有害气体的浓度进行测

量，确认是安全的条件下方可进行测量。

４

GB/T21246—2007

4.5电位极性

4.5.1管地电位测量中采用直流数字式电压表时，应将电压表的负接线柱（COM）与硫酸铜电极

连接，正接线柱（V）与管道连接，管地电位测量接线见图1。仪表指示的是管道相对于参比电极的

电位值，正常情况下显示负值。

4.5.2当采用直流指针式电压表测量管地电位时，应采用测量接线图2方式，在指针没有发生反转

的情况下，所记录的数据应该加负号。

数字万用表

参比电极

测量导线

接管道

管道

图1数字万用表管地电位测量接线图

指针式电压表

参比电极

测量导线

接管道

管道

图2指针式电压表管地电位测量接线图

５

GB/T××××—2006

5电位测量

5.1自然电位

5.1.1适用性

本方法适用于未施加阴极保护电流的管道腐蚀电位（自然电位）的测量。

5.1.2测量步骤

1)测量前，应确认管道是处于没有施加阴极保护的状态下。对已实施过阴极保护的管道宜在

完全断电24h后进行。

2)测量时，将硫酸铜电极放置在管顶正上方地表的潮湿土壤上，应保证硫酸铜电极底部与土

壤接触良好。

3)按图1或图2的测量接线方式，将电压表与管道及硫酸铜电极相连接。

4)将电压表调至适宜的量程上，读取数据，作好管地电位值及极性记录，注明该电位值的名

称。

5.2通电电位

5.2.1适用性

本方法适用于施加阴极保护电流时，管道对电解质（土壤、水）电位的测量。本方法测得的电

位是极化电位与回路中所有电压降的和，即含有除管道金属/电解质界面以外的所有电压降。

5.2.2测量步骤

1)测量前，应确认阴极保护运行正常，管道已充分极化。

2)测量时，将硫酸铜电极放置在管顶正上方地表的潮湿土壤上，应保证硫酸铜电极底部与土

壤接触良好。

3)管地通电电位测量接线见图1或图2。

4)将电压表调至适宜的量程上，读取数据，作好管地电位值及极性记录，注明该电位值的名

称。

5.3断电电位

5.3.1适用性

本方法适用于管道对电解质极化电位的测量。本方法测得的断电电位（V）是消除了由保护电

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流所引起的IR降后的管道保护电位。对有直流杂散电流或保护电流不能同步中断（多组牺牲阳极或

其与管道直接相接，或存在不能被中断的外部强制电流设备）的管道本方法不适用。

5.3.2测量步骤

1)在测量之前，应确认阴极保护正常运行，管道已充分极化。

2)测量时，在所有电流能流入测量区间的阴极保护电源处安装电流同步断续器，并设置在合

理的周期性通/断循环状态下同步运行，同步误差小于0.1s。合理的通/断循环周期和断电时

６

GB/T21246—2007

间设置原则是：断电时间应尽可能的短，以避免管道明显的去极化，但又应有足够长的时

间保证测量采集及在消除冲击电压影响后读数。为了避免管道明显的去极化，断电期宜不

大于3s，典型的通/断周期设置为：通电12s，断电3s。

3)将硫酸铜电极放置在管顶正上方地表的潮湿土壤上，应保证硫酸铜电极底部与土壤接触良

好。

4)管地断电电位（V）测量接线见图1或图2。

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5)将电压表调至适宜的量程上，读取数据，读数应在通/断电0.5s之后进行。

6)记录下管道对电解质的通电电位（V）和断电电位（V），以及相对于硫酸铜电极的极性。

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所测得的断电电位（V），即为硫酸铜电极安放处的管道保护电位。

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7)如果对冲击电压的影响存在怀疑时，应使用脉冲示波器或高速记录仪对所测结果进行核实。

5.4密间隔电位

5.4.1适用性

密间隔电位测量（CIPS）适用于对管道阴极保护系统的有效性进行全面评价的测试。本方法可

测得管道沿线的通电电位（V）和断电电位（V），结合直流电位梯度法（DCVG）可以全面评价

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管线阴极保护系统的状况和查找防腐层破损点及识别腐蚀活跃点。对保护电流不能同步中断（多组

牺牲阳极或其与管道直接相接，或存在不能被中断的外部强制电流设备），以及套管内的破损点未被

电解质淹没的管道本方法不适用。另外下列情况会使本方法应用困难或测量结果的准确性受到影响：

1)覆盖层导电性很差的管段，如铺砌路面、冻土、钢筋混凝土、含有大量岩石回填物；

2)剥离防腐层下或绝缘物造成电屏蔽的位置，如破损点处外包覆或衬垫绝缘物的管道。

5.4.2测量步骤

1)测量简图见图3。

米尺线轴

CIPS测量主机或

数字万用表

+-

同步断续器

CSE

阴极保护

电源

图3CIPS测量简图

2)在测量之前，应确认阴极保护正常运行，管道已充分极化。

3)在测量之前，检查测量主机电池电量。

７

GB/T××××—2006

4)在所有电流能流入测量区间的阴极保护直流电源处安装电流同步断续器，并设置在合理的

周期性通/断循环状态下同步运行，同步误差小于0.1s。设置原则是：断电时间应尽可能的

短，以避免管道明显的去极化，但又应有足够长的时间保证能在消除冲击电压影响后测量

采集数据。根据具体所用的阴极保护电源设备和测量仪器的不同，典型的循环时间设置宜

为：通电800ms，断电200ms或通电4s，断电1s或通电12s，断电3s。

5)将线轴（长测量导线）一端与CIPS/DCVG测量主机（或数字式万用表）连接，另一端与测

试桩连接，将一根探杖（硫酸铜电极）与CIPS/DCVG测量主机（或数字式万用表）连接。

6)打开CIPS/DCVG测量主机，设置为CIPS测量模式，设置与同步断续器保持同步运行的相

同的通/断循环时间和断电时间，并设置合理的断电电位测量延迟时间，典型的延迟时间设

置宜为50~100ms。

7)测量时，利用探管仪对管道定位，保证硫酸铜电极放置在管道的正上方。

8)从测试桩开始，沿管线管顶地表以密间隔（一般是1~3m）逐次移动探杖（硫酸铜电极），

每移动探杖一次就采集并记录存储一组通电电位（V）和一组断电电位（V），直至到达

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前方一个测试桩。按此完成全线管地电位沿管道变化的测量。

9)同时应使用米尺线轴、GPS坐标测量或其它方法，测量硫酸铜电极安放处沿管线的距离，应

对沿线的永久性标志、参照物及它们的位置等信息进行记录，并应对管道通电电位（V）

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和断电电位（V）异常位置处作好标志与记录。

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10)某段密间隔测量完成后，若当天不再测量，应通知阴极保护站恢复为连续供电状态。

5.4.3数据处理

1)将现场测量数据下载到计算机中，进行数据处理分析。

2)对每处两组数据中的几个数据，分别取其算术平均值，代表该测量点的通电电位（V）和

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断电电位（V）。

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3)以距离为横坐标、电位为纵坐标绘出测量段的电位分布曲线图，图中一条为通电电位曲线，

另一条为断电电位曲线，在直流干扰和平衡电流影响可忽略不计地方，断电电位曲线代表

阴极保护保护电位分布曲线。

5.5消除IR降电位

5.5.1适用性

电位准确测量技术适用于防腐层破损点多的管段的断电电位的修正测试；可识别防腐层破损点

位置，并能计算出破损处消除IR降电位。对防腐层破损点多的管道进行断电电位测试时，仅能消除

保护电流所引起的电压降（IR降）影响，而各破损点间存在极化电位差引起的平衡电流会使所测得

的断电电位被歪曲。

5.5.2方法介绍

８

GB/T21246—2007

一种沿管道以最大5m间隔放置参比电极，采用密间隔电位法（CIPS）测量管顶上方管地电位，

同时测量出相对应的与管道垂直的（间隔10m）电位梯度，经计算获得消除IR降的管道/土壤界面

电位的测量技术。

5.5.3测量方法

1)电位准确测量技术测量简图见图4。

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管线0m

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I

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图4电位准确测量技术测量简图

2)在防腐层破损点多的被测量区域管段，按第5.4密间隔管地电位测量法采集并记录存储管道

正上方（如图A点）的通电电位V和断电电位V。

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3)采用已校准过的另一支硫酸铜电极，将其置于与管道方向相垂