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GB/T 31838 consists of the following parts, under the general title Solid Insulating Materials — Dielectric and Resistive Properties: Solid Insulating Materials — Dielectric and Resistive Properties:
— Part 1: General
— Part 2: Resistive Properties (DC Methods) — Volume Resistance and Volume Resistivity;
— Part 3: Resistive Properties (DC Methods) — Surface Resistance and Surface Resistivity;
— Part 4: Resistive Properties (DC Methods) — Insulation Resistance.
This part is Part 2 of GB/T 31838.
This part is drafted in accordance with the rules given in the GB/T 1.1-2009
This part replaces GB/T 1410-2006 Methods of Test for Volume Resistivity and Surface Resistivity of Solid Electrical Insulating Materials, and the following technical deviations have been made with respect to the GB/T 1410-2006 (the previous edition):
— modification of the Normative References (see Clause 2; Clause 2 of Edition 2006);
— deletion of the terms of “surface resistance”, “surface resistivity” and “electrodes” (see 3.3, 3.4 and 3.5 of Edition 2006);
— addition of the term of “stray current” (see 3.3);
— combination of the “Power Supply”, “Accuracy”, “Guarding”, “Test Specimens”, “Electrode Material”, “Specimen Handling”, “Conditioning” into “Method of Test” (see Clause 5; Clause 5, 6.2, 6.3, Clause 7 to Clause 10 of Edition 2006);
— combination of the “Measuring Methods”, “Test Procedure”, “Volume resistivity” into “Test Procedure” (see Clause 6; 6.1, Clause 11, 12.1 of Edition 2006);
— deletion of the “Surface resistance” and “Surface resistivity” (see 11.2 and 12.2 of Edition 2006);
— modification of the “Reproducibility” (see Clause 8; 12.3 of Edition 2006) .
— deletion of the Annexes A, B and C (Annexes A, B and C of Edition 2006);
This part is identical with International Standard IEC 62631-3-1:2016 Dielectric and Resistive Properties of Solid Insulating Materials — Part 3-1: Determination of Resistive Properties (DC methods) — Volume Resistance and Volume Resistivity — General Method.
The Chinese documents consistent and corresponding with the normative international documents in this part are as follows:
— GB/T 1981.2-2009 Varnishes Used for Electrical Insulation — Part 2: Methods of Test (IEC 60464-2:2001 and Amendment 1:2006, MOD);
— GB/T 1981.3-2009 Varnishes Used for Electrical Insulation — Part 3: Specifications for Hot Curing Impregnating Varnishes (IEC 60464-3-2:2001, IDT);
— GB/T 2411-2008 Plastics and Ebonite — Determination of Indentation Hardness by Means of a Durometer (Shore Hardness) (ISO 868:2003, IDT);
— GB/T 5132.1-2009 Industrial Rigid Round Laminated Tubes and Rods Based on Thermosetting Resins for Electrical Purposes — Part 1: General Requirements (IEC 61212-1:2006, IDT);
— GB/T 5132.2-2009 Industrial Rigid Round Laminated Tubes and Rods Based on Thermosetting Resins for Electrical Purposes — Part 2: Methods of Test (IEC 61212-2:2006, IDT);
— GB/T 5132.5-2009 Industrial Rigid Round Laminated Tubes and Rods Based on Thermosetting Resins for Electrical Purposes — Part 5: Round Laminated Moulded Rods (IEC 61212-3-3:2006, IDT);
— GB/T 6554-2003 Resin Based Reactive Compounds Used for Electrical Insulation — Part 2: Methods of Test — Methods for Coating Powders for Electrical Purposes (IEC 60455-2-2:1984, MOD);
— GB/T 10580-2015 Standard Conditions for Use Prior to and During the Testing of Solid Electrical Insulating Materials (IEC 60212:2010, IDT);
— GB/T 15022.1-2009 Resin Based Reactive Compounds Used for Electrical Insulation — Part 1: Definitions and General Requirements (IEC 60455-1:1998, IDT);
— GB/T 15022.2-2017 Resin Based Reactive Compounds Used for Electrical Insulation — Part 2: Methods of Test (IEC 60455-2:2015, NEQ);
— GB/T 15022.3-2011 Resin Based Reactive Compounds Used for Electrical Insulation — Part 3: Unfilled Epoxy Resinous Compounds (IEC 60455-3-1:2003, IDT);
— GB/T 15022.4-2009 Resin Based Reactive Compounds Used for Electrical Insulation — Part 4: Unsaturated Polyester Based Impregnating Resins (IEC 60455-3-5:2006, MOD);
— GB/T 15022.5-2011 Resin Based Reactive Compounds Used for Electrical Insulation — Part 5: Quartz Filled Epoxy Resinous Compounds (IEC 60455-3-2:2003, MOD).
For the purposes of this part, the following editorial changes have also been made:
— change of the standard name to Solid Insulating Materials — Dielectric and Resistive Properties — Part 2: Resistive Properties (DC Methods) — Volume Resistance and Volume Resistivity.
This standard was proposed by China Electrical Equipment Industrial Association.
This standard is under the jurisdiction of SAC/TC 301 (National Technical Committee 301 on Evaluation and Qualification of Electrical Insulating Material and Systems of Standardization Administration of China).
The previous editions of this part are as follows:
— GB/T 1410-2006
Solid Insulating Materials — Dielectric and Resistive Properties — Part 2: Resistive Properties (DC Methods) — Volume Resistance and Volume Resistivity
1 Scope
This part of GB/T 31838 specifies a method of test for the determination of volume resistance and volume resistivity of electrical insulation materials by applying a DC voltage.
2 Normative References
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
IEC 60212 Standard Conditions for Use Prior to and During the Testing of Solid Electrical Insulating Materials
IEC 60455 (all parts) Resin Based Reactive Compounds Used for Electrical Insulation
IEC 60464 (all parts) Varnishes Used for Electrical Insulation
IEC 61212 (all parts) Industrial Rigid Round Laminated Tubes and Rods Based on Thermosetting Resins for Electrical Purposes
ISO 868 Plastics and Ebonite — Determination of Indentation Hardness by Means of a Durometer (Shore Hardness)
3 Terms and Definitions
For the purposes of this document, the following terms and definitions apply.
3.1
volume resistance
the quotient of a direct voltage applied between two electrodes placed on two faces (opposite) of a specimen, and the steady-state current between the electrodes
Note: Volume resistance is expressed in the unit of Ω.
3.2
volume resistivity
the quotient of a d.c. electric field strength and the steady-state current density within an insulating material. In practice it is taken as the volume resistance reduced to a cubical unit volume
Note 1: According to IEC 60050-121, “conductivity” is defined as “scalar or tensor quantity, the product of which by the electric field strength in a medium is equal to the electric current density” and “resistivity” as “the inverse of the conductivity when this inverse exists”. Measured in this way, the volume resistivity is an average of the resistivity over possible heterogeneities in the volume incorporated in the measurement; it includes the effect of possible polarization phenomena at the electrodes.
Note 2: For insulating materials, the volume resistivity is usually determined by means of measuring electrodes arranged on a sheet of the material.
Note 3: Volume resistivity is expressed in the unit of Ωm.
3.3
stray current
leakage current in the earth or in metallic structures buried in the ground and resulting from their intended or unintended earthing
4 Significance
Insulating materials are used in general to electrically isolate components of an electrical system from each other and from earth. Solid insulating material may also provide mechanical support. For these purposes it is generally desirable to have the insulation resistance as high as possible, consistent with acceptable mechanical, chemical and heat resistance properties. Volume resistance is a part of the insulating resistance.
Volume resistivity can be used as an aid in the choice of an insulating material for a specific application. The change in resistivity with temperature and humidity may be great and has to be known when designing for operation conditions.
When a direct voltage is applied between electrodes in contact with a specimen, the current through it decreases asymptotically towards a steady-state value. The decrease of current with time may be due to dielectric polarization and the sweep of mobile ions to the electrodes. For materials having volume resistivity less than about 1010 Ωm the steady state is generally reached within 1 min and the resistance is determined after this time of electrification. For materials with higher volume resistivity the current may continue decreasing for several minutes, hours, days or even weeks. For such materials, therefore, longer electrification times may be necessary.
Note: For very high electric field strengths different behaviour can occur.
5 Method of Test
5.1 General
This general method describes common values for general measurements. If a method for a specific type of material is described in this standard, the specific method shall be used.
The measurement of volume resistance (and volume resistivity respectively) shall be carried out carefully and taking into account the electric properties of the measuring circuit as well as the specific electric properties of the material.
To carry out the test, in most cases the use of high voltages is necessary. Care shall be taken to prevent electric shock.
Polarization effects can influence the measurement. Therefore it is not acceptable to achieve the measured resistance twice in two consecutive experiments without a sufficient space of time in-between.
Note: For materials with volume resistance of not more than 1012Ω a period of 1 h after voltage application might be sufficient.
5.2 Power supply and voltage
A source of very steady direct voltage is required. This may be provided either by batteries or by rectified and stabilized power supply. The degree of stability required is such that the change in current due to any change in voltage is negligible compared with the current to be measured.
Note 1: The ripple of the voltage source is important. A typical value for 100 V is < 5×10-5 peak to peak.
Commonly specified test voltages to be applied to the complete specimen are 10 V, 100 V, 500 V, 1 000 V, and 10 000 V. If not otherwise stipulated, a voltage of 100 V is to be used.
Note 2: In air, below 340 V no partial discharges will occur. Partial discharge can lead to erroneous measurements of the resistance when a specific inception voltage is exceeded.
Foreword II 1 Scope 2 Normative References 3 Terms and Definitions 4 Significance 5 Method of Test 6 Test Procedure 7 Test Report 8 Repeatability and Reproducibility Bibliography
ICS 29.035.01 K 15 中华人民共和国国家标准 GB/T 31838.2—2019/IEC 62631-3-1：2016 代替GB/T 1410—2006 固体绝缘材料 介电和电阻特性 第2部分：电阻特性(DC方法) 体积电阻和体积电阻率 Solid insulating materials—Dielectric and resistive properties— Part 2：Resistive properties(DC methods)— Volume resistance and volume resistivity [IEC 62631-3-1：2016，Dielectric and resistive properties of solid insulating materials—Part 3-1：Determination of resistive properties(DC methods)— Volume resistance and volume resistivity—General method，IDT] 2019-06-04发布 2020-01-01实施 国家市场监督管理总局 中国国家标准化管理委员会 发布 前言 GB/T 31838《固体绝缘材料 介电和电阻特性》目前发布以下部分： ——第1部分：总则； ——第2部分：电阻特性(DC方法) 体积电阻和体积电阻率； ——第3部分：电阻特性(DC方法) 表面电阻和表面电阻率； ——第4部分：电阻特性(DC方法) 绝缘电阻。 本部分为GB/T 31838的第2部分。 本部分按照GB/T 1.1—2009给出的规则起草。 本部分代替GB/T 1410—2006《固体绝缘材料体积电阻率和表面电阻试验方法》，与GB/T 1410—2006相比主要技术变化如下： ——修改了规范性引用文件(见第2章，2006年版的第2章)； ——删除了“表面电阻”“表面电阻率”和“电极”等术语(见2006年版的3.3、3.4、3.5)； ——增加了“杂散电流”术语(见3.3)； ——将“电源、精确度、保护、试样、电极材料、试样处置、条件处理”等整合为“试验方法”(见第5章，2006年版的第5章、6.2、6.3、第7章～第10章)； ——将“测量方法、试验程序、体积电阻率”整合为“试验程序”(见第6章，2006年版的6.1、第11章、12.1)； ——删除了“表面电阻”和“表面电阻率的计算”(见2006年版的11.2和12.2)； ——修改了“重现性”(见第8章，2006年版的12.3)； ——删除了附录A、附录B、附录C(2006年版的附录A、附录B和附录C)。 本部分使用翻译法等同采用IEC 62631-3-1：2016《固体绝缘材料的介电和电阻特性 第3-1部分：确定电阻特性(DC方法) 体积电阻和体积电阻率 一般方法》。 与本部分中规范性引用的国际文件有一致性对应关系的我国文件如下： ——GB/T 1981.2—2009 电气绝缘用漆 第2部分：试验方法(IEC 60464-2：2001及2006第1次修订，MOD)； ——GB/T 1981.3—2009 电气绝缘用漆 第3部分：热固化浸渍漆通用规范(IEC 60464-3-2：2001，IDT)； ——GB/T 2411—2008塑料和硬橡胶 使用硬度计测定压痕硬度(邵氏硬度)(IS0 868：2003，IDT)； ——GB/T 5132.1—2009 电气用热固性树脂工业硬质圆形层压管和棒 第1部分：一般要求(IEC 61212-1：2006，IDT)； ——GB/T 5132.2—2009 电气用热固性树脂工业硬质圆形层压管和棒 第2部分：试验方法(IEC 61212-2：2006，IDT)； ——GB/T 5132.5—2009 电气用热固性树脂工业硬质圆形层压管和棒 第5部分：圆形层压模制棒(IEC 61212-3-3：2006，IDT)； ——GB/T 6554—2003 电气绝缘用树脂基反应复合物 第2部分：试验方法 电气用涂敷粉末方法(IEC 60455-2-2：1984，MOD)； ——GB/T 10580—2015固体绝缘材料在试验前和试验时采用的标准条件(IEC 60212：2010，IDT)； ——GB/T 15022.1—2009 电气绝缘用树脂基活性复合物 第1部分：定义及一般要求(IEC 60455-1：1998，IDT)； ——GB/T 15022.2—2017 电气绝缘用树脂基活性复合物 第2部分：试验方法(IEC 60455-2：2015，NEQ)； ——GB/T 15022.3—2011 电气绝缘用树脂基活性复合物 第3部分：无填料环氧树脂复合物(IEC 60455-3-1：2003，IDT)； ——GB/T 15022.4—2009 电气绝缘用树脂基活性复合物 第4部分：不饱和聚酯为基的浸渍树脂(IEC 60455-3-5：2006，MOD)； ——GB/T 15022.5—2011 电气绝缘用树脂基活性复合物 第5部分：石英填料环氧树脂复合物(IEC 60455-3-2：2003，MOD)。 本部分做了下列编辑性修改： ——将标准名称修改为《固体绝缘材料 介电和电阻特性 第2部分：电阻特性(DC方法) 体积电阻和体积电阻率》。 本部分由中国电器工业协会提出。 本部分由全国电气绝缘材料与绝缘系统评定标准化技术委员会(SAC/TC 301)归口。 本部分所代替标准的历次版本发布情况为： ——GB/T 1410—2006。 固体绝缘材料 介电和电阻特性 第2部分：电阻特性(DC方法) 体积电阻和体积电阻率 1 范围 GB/T 31838的本部分规定了直流电压下确定固体绝缘材料体积电阻和体积电阻率的试验方法。 2规范性引用文件 下列文件对于本文件的应用是必不可少的。凡是注日期的引用文件，仅注日期的版本适用于本文件。凡是不注日期的引用文件，其最新版本(包括所有的修改单)适用于本文件。 IEC 60212 固体绝缘材料在试验前和试验时采用韵标准条件(Standard conditions for use prior to and during the testing of solid electrical insulating materials) IEC 60455(所有部分) 电气绝缘用树脂基活性复合物(Resin based reactive compounds used for electrical insulation) IEC 60464(所有部分) 电气绝缘用漆(Varnishes used for electrical insulation) IEC 61212(所有部分) 电气用热固性树脂工业硬质圆形层压管和棒(Industrial rigid round lami-nated tubes and rods based on thermosetting resins for electrical purposes) IS0 868塑料和硬质橡胶 使用硬度计测定压痕硬度(邵氏硬度)[Plastics and ebonite—Deter-mination of indentation hardness by means of a durometer(Shore hardness)] 3术语和定义 下列术语和定义适用于本文件。 3.1 体积电阻 volume resistance 施加在与绝缘介质相对表面接触的两个电极间的直流电压与给定时间流过介质的电流之比。 注：体积电阻的单位用Ω表示。 3.2 体积电阻率volume resistivity 在给定的时间及电压下，直流电场强度与绝缘介质内部电流密度之比。 注1：根据IEC 60050-121，“电导率”被定义为标量或张量，它与电场强度的乘积是传导电流密度；“电阻率”是“电导率”的倒数。体积电阻率是在测量时单位体积内可能存在的各向异性的数量的平均值，还包括在电极间可能产生的极化现象。 注2：在实际中，体积电阻率通常被视为单位体积内的体积电阻。 注3：体积电阻率的单位用Ω·m表示。 3.3 杂散电流 stray current 对地的或埋在地下的金属结构接地而引起的泄漏电流。 4意义 绝缘材料通常用于将电气系统中各组件之间或组件对地之间进行电气隔离。固体绝缘材料还起到机械支撑的作用。因此，在应用绝缘材料时，期望其具有尽可能高的绝缘电阻及得到认可的机械性能、化学和耐热性能。体积电阻是材料绝缘电阻的一部分。 体积电阻率可作为选用合适的绝缘材料的一个辅助方法，其可能随测量温度和湿度的变化而显著变化，因此在选用材料时，应了解其使用条件和环境。 当直流电压施加到两电极之间的试样上时，通过试样的电流会逐渐减小到一个稳定值。电流随时间的减小可能是由于介质的极化和载流子迁移到电极所致。对于体积电阻率小于1010 Ω·m的材料，电流通常在1 min内即可达到稳定状态。对于具有更高体积电阻率的材料，电流减小并趋于稳定的过程可能会持续几分钟、几小时、几天甚至几周。因此，对于这样的材料，可采用较长的施加电压时间。 注：当电场强度非常高时，会产生其他不同的现象。 5试验方法 5.1 概述 一般方法给出了可被普遍用于各类材料的测量方法，对于一个特定类型的材料，应使用本部分规定的特定的试验方法。 体积电阻和体积电阻率的测量应考虑测量电路的特性以及该材料的特有电性能。 试验时，所施加的试验电压很高，应注意防止触电。 试验施加电压所产生的极化效应会影响下一次的测量结果，因此连续两次测量期间应保证足够长的时间间隔。以消除极化效应。 注：对于体积电阻不大于1012 Ω的材料。1 h的时间间隔是足够的。 5.2电源与电压 所施加电压源应为稳定的直流电压源，可由蓄电池或整流稳压电源提供。对于电源的稳定度，由电压不稳所引起的电流变化应足够小，而不影响测量的有效性。 注1：电压源的纹波特性是十分具有参考价值的，电源电压为100 V时，纹渡系数小于5×10-5。 试验电压通常规定为10 V、100 V、500 V、1 000 V和10 000 V。如无特殊规定，推荐采用100 V电压。 注2：超过规定的起始电压会引起局部放电，可能导致测量误差。若在空气中进行试验时，试验电压低于340 V，不会引起局部放电。 5.3 设备 5.3.1 精确度 可采用任何合适的设备，但测量装置的精确度至少满足下列要求： ——电阻低于1010 Ω，测量误差不大于±10％； ——电阻介于1010 Ω到1014 Ω之间，测量误差不大于±20％； ——电阻高于1014 Ω，测量误差不大于±50％。 5.3.2 保护 组成测量线路的绝缘材料，宜具有与被测材料近似的特性。下列原因可能导致测量产生误差： ——外来寄生电压引起的杂散电流，通常其大小未知，并具有漂移特性； ——具有未知而易变的电阻值的绝缘与试样电阻、标准电阻器或电流测量装置的不正常的分路； ——表面电阻可能比体积电阻低一个数量级。 通过尽可能地提高测量线路所有部分的绝缘电阻，来近似地更正上述误差。但这种做法可能导致测量设备复杂且笨重，而又不足以测量高于几百兆欧的绝缘电阻。可通过使用保护技术来实现更为合适的修正。 保护是指在所有关键的绝缘部位插入保护导体，可阻拦所有可能引起误差的杂散电流。这些保护导体联接在一起，组成保护系统，并与测量端形成三电极系统。当线路连接恰当时，所有外来寄生电压产生的杂散电流被保护系统分流到测量电路以外，任一测量端到保护系统的绝缘电阻宜与比电阻低得多的线路元件并联，试样电阻仅指两测量电极之间的绝缘电阻.采用这个技术可大大减小误差概率。 图1为使用保护电极测量体积电阻的基本线路。
