GB/T 1408.2-2016 English PDF (GB/T1408.2-2016)

GB/T 1408.2-2016: Insulating materials -- Test methods for electric strength -- Part 2: Additional requirements for tests using direct voltage
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GB/T 1408.2-2016
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 29.035.99
K 15
GB/T 1408.2-2016 / IEC 60243-2:2013
Replacing GB/T 1408.2-2006
Insulating Materials – Test Methods for Electric Strength –
Part 2: Additional Requirements for Tests Using Direct Voltage
(IEC 60243-2:2013, Electric Strength of Insulating Materials – Test
Methods – Part 2: Additional Requirements for Tests Using Direct Voltage, IDT)
ISSUED ON: DECEMBER 13, 2016
IMPLEMENTED ON: JULY 1, 2017
Issued by: General Administration of Quality Supervision, Inspection and
Quarantine;
Standardization Administration of the People’s Republic of China.
Table of Contents
Foreword ... 3
1 Scope ... 5
2 Normative References ... 5
3 Terms and Definitions ... 5
4 Significance of the Test ... 5
5 Electrodes and Test Specimens ... 6
6 Conditioning before Tests ... 6
7 Surrounding Medium ... 6
8 Electrical Apparatus ... 6
9 Procedure ... 7
10 Mode of Increase of Voltage ... 7
11 Criterion of Breakdown ... 8
12 Number of Tests... 8
13 Report ... 8
Bibliography ... 9
Foreword
GB/T 1408 Electrical Strength of Insulating Materials - Test Methods consists of the following
3 parts:
--- Part 1: Tests at Power Frequencies;
--- Part 2: Additional Requirements for Tests Using Direct Voltage;
--- Part 3: Additional Requirements for 1.2/50μs Impulse Tests.
This Part is Part 2 of GB/T 1408.
This Standard was drafted as per the rules specified in GB/T 1.1-2009.
This Part replaced GB/T 1408.2-2006 Electrical Strength of Insulating Materials - Test Methods
- Part 2: Additional Requirements for Tests Using Direct Voltage. Compared with GB/T 1408.2-
2006, the major technical changes of this Part are as follows:
--- Modify GB/T 1408.1-2006 INTO “GB/T 1408.1-2016” in the whole text;
--- Delete 10 reference documents including GB/T 1981.2-2003;
--- Modify the report content;
--- Add Bibliography.
This Part uses translation method to equivalently adopt IEC 60243-2:2013 Electric Strength of
Insulating Materials – Test Methods – Part 2: Additional Requirements for Tests Using Direct
Voltage (The 3rd Version).
This Part was proposed by China Electrical Equipment Industry Association.
This Part shall be under the jurisdiction of National Technical Committee on Electrical
Insulating Materials and Insulating System Evaluation of Standardization Administration of
China (SAC/TC 301).
Drafting organizations of this Part: Suzhou Taihu Electric Advanced Material Co., Ltd.;
Machinery Industry Beijing Electrotechnical Institute of Economic Research; Shanghai Electric
Cable Research Institute; Guilin Electrical Equipment Scientific Research Institute Co., Ltd.;
and Sichuan EM Technology Co., Ltd.
Chief drafting staffs of this Part: Liu Yali, Zhang Chunqi, Xia Junfeng, Xia Zhifeng, Wu Bin,
Cheng Hao, Wang Xianfeng, Zhao Ping, and Li Jiexia.
The historical edition replaced by this Part is as follows:
Insulating Materials – Test Methods for Electric Strength –
Part 2: Additional Requirements for Tests Using Direct Voltage
1 Scope
This Part of GB/T 1408 gives requirements additional to those in GB/T 1408.1 for the
determination of the electric strength of solid insulating materials under direct voltage stress.
2 Normative References
The following documents are essential to the application of this Document. For the dated
documents, only the versions with the dates indicated are applicable to this Document; for the
undated documents, only the latest version (including all the amendments) is applicable to this
Document.
GB/T 1408.1-2016 Electrical strength of insulating materials - Test methods - Part 1: Tests
at power frequencies (IEC 60243-1:2013, IDT)
3 Terms and Definitions
For the purposes of this Document, the terms and definitions given in GB/T 1408.1-2016 apply.
4 Significance of the Test
In addition to the requirements of Clause 4 of GB/T 1408.1-2016, the following points shall be
considered when using direct-voltage tests.
For a non-homogeneous test specimen, with alternating voltage, the distribution of voltage
stress within the test specimen is determined by impedance (largely capacitive). With an
increasing direct voltage, the voltage distribution may still be largely capacitive but depends
partly on the rate of voltage increase. The resistive voltage distribution, after constant voltage
application, represents the steady-state condition. The choice between direct or alternating
voltage depends upon the purpose for which the breakdown test is to be used and, to some
extent, on the intended application of the material.
Upon direct voltage application, the following currents result: the capacitive current, the electric
transients in initiating premature breakdowns.
The controls on voltage shall be capable of varying the test voltage smoothly and uniformly
between zero and the maximum test voltage and with the requested rate of voltage rise. The
rate of voltage rise shall be controllable within ±20 % of the specified rate. Steps in voltage rise
shall not exceed 2 % of the expected breakdown voltage value. Controls which automatically
increase the voltage at a selectable rate are preferable.
A current-sensitive interrupting device shall be used for switching off the direct voltage source.
For many materials, a dangerous voltage may persist across the test specimen for a considerable
time after the d.c. test voltage is removed. Disconnection of the power supply to the direct
voltage source does not necessarily result in the output voltage or the voltage at the electrodes
being reduced to zero. For this reason, it is essential that the electrodes be short-circuited and
connected to earth for a period equal to minimum twice the total charging time to ensure that
the charge is dissipated. For some large test specimens, it will be necessary to maintain the
shorted condition for 1 h or even longer.
A current-limiting resistance shall be used in series with the test specimen to prevent damage
to the high-voltage supply and to limit as far as possible the damage to the electrodes on the
test specimen when breakdown takes place. The maximum current permitted will depend on
the material under test and on the amount of damage to the electrodes which can be tolerated.
NOTE 1: The use of a very high-valued resistor may result in breakdown voltages which are higher than
those obtained with a lower-valued resistor.
When making tests where the value or increase in the value of the current is used as a criterion
for breakdown, means of measurement of current through the test specimen shall be provided.
8.2 Voltage Measurement
The measurement of applied voltage shall be made across the electrodes. The other
requirements of Clause 8 of GB/T 1408.1-2016 shall be met.
9 Procedure
Clause 9 of GB/T 1408.1-2016 is applicable.
10 Mode of Increase of Voltage
Unless otherwise specified, the voltage shall be applied in accordance with 10.1 (short-time
test), 10.3 or 10.5 (slow and very slow rate-of-rise tests) or 10.6 (proof tests) of GB/T 1408.1-
2016.
GB/T 1408.2-2016
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 29.035.99
K 15
GB/T 1408.2-2016 / IEC 60243-2:2013
Replacing GB/T 1408.2-2006
Insulating Materials – Test Methods for Electric Strength –
Part 2: Additional Requirements for Tests Using Direct Voltage
(IEC 60243-2:2013, Electric Strength of Insulating Materials – Test
Methods – Part 2: Additional Requirements for Tests Using Direct Voltage, IDT)
ISSUED ON: DECEMBER 13, 2016
IMPLEMENTED ON: JULY 1, 2017
Issued by: General Administration of Quality Supervision, Inspection and
Quarantine;
Standardization Administration of the People’s Republic of China.
Table of Contents
Foreword ... 3
1 Scope ... 5
2 Normative References ... 5
3 Terms and Definitions ... 5
4 Significance of the Test ... 5
5 Electrodes and Test Specimens ... 6
6 Conditioning before Tests ... 6
7 Surrounding Medium ... 6
8 Electrical Apparatus ... 6
9 Procedure ... 7
10 Mode of Increase of Voltage ... 7
11 Criterion of Breakdown ... 8
12 Number of Tests... 8
13 Report ... 8
Bibliography ... 9
Foreword
GB/T 1408 Electrical Strength of Insulating Materials - Test Methods consists of the following
3 parts:
--- Part 1: Tests at Power Frequencies;
--- Part 2: Additional Requirements for Tests Using Direct Voltage;
--- Part 3: Additional Requirements for 1.2/50μs Impulse Tests.
This Part is Part 2 of GB/T 1408.
This Standard was drafted as per the rules specified in GB/T 1.1-2009.
This Part replaced GB/T 1408.2-2006 Electrical Strength of Insulating Materials - Test Methods
- Part 2: Additional Requirements for Tests Using Direct Voltage. Compared with GB/T 1408.2-
2006, the major technical changes of this Part are as follows:
--- Modify GB/T 1408.1-2006 INTO “GB/T 1408.1-2016” in the whole text;
--- Delete 10 reference documents including GB/T 1981.2-2003;
--- Modify the report content;
--- Add Bibliography.
This Part uses translation method to equivalently adopt IEC 60243-2:2013 Electric Strength of
Insulating Materials – Test Methods – Part 2: Additional Requirements for Tests Using Direct
Voltage (The 3rd Version).
This Part was proposed by China Electrical Equipment Industry Association.
This Part shall be under the jurisdiction of National Technical Committee on Electrical
Insulating Materials and Insulating System Evaluation of Standardization Administration of
China (SAC/TC 301).
Drafting organizations of this Part: Suzhou Taihu Electric Advanced Material Co., Ltd.;
Machinery Industry Beijing Electrotechnical Institute of Economic Research; Shanghai Electric
Cable Research Institute; Guilin Electrical Equipment Scientific Research Institute Co., Ltd.;
and Sichuan EM Technology Co., Ltd.
Chief drafting staffs of this Part: Liu Yali, Zhang Chunqi, Xia Junfeng, Xia Zhifeng, Wu Bin,
Cheng Hao, Wang Xianfeng, Zhao Ping, and Li Jiexia.
The historical edition replaced by this Part is as follows:
Insulating Materials – Test Methods for Electric Strength –
Part 2: Additional Requirements for Tests Using Direct Voltage
1 Scope
This Part of GB/T 1408 gives requirements additional to those in GB/T 1408.1 for the
determination of the electric strength of solid insulating materials under direct voltage stress.
2 Normative References
The following documents are essential to the application of this Document. For the dated
documents, only the versions with the dates indicated are applicable to this Document; for the
undated documents, only the latest version (including all the amendments) is applicable to this
Document.
GB/T 1408.1-2016 Electrical strength of insulating materials - Test methods - Part 1: Tests
at power frequencies (IEC 60243-1:2013, IDT)
3 Terms and Definitions
For the purposes of this Document, the terms and definitions given in GB/T 1408.1-2016 apply.
4 Significance of the Test
In addition to the requirements of Clause 4 of GB/T 1408.1-2016, the following points shall be
considered when using direct-voltage tests.
For a non-homogeneous test specimen, with alternating voltage, the distribution of voltage
stress within the test specimen is determined by impedance (largely capacitive). With an
increasing direct voltage, the voltage distribution may still be largely capacitive but depends
partly on the rate of voltage increase. The resistive voltage distribution, after constant voltage
application, represents the steady-state condition. The choice between direct or alternating
voltage depends upon the purpose for which the breakdown test is to be used and, to some
extent, on the intended application of the material.
Upon direct voltage application, the following currents result: the capacitive current, the electric
transients in initiating premature breakdowns.
The controls on voltage shall be capable of varying the test voltage smoothly and uniformly
between zero and the maximum test voltage and with the requested rate of voltage rise. The
rate of voltage rise shall be controllable within ±20 % of the specified rate. Steps in voltage rise
shall not exceed 2 % of the expected breakdown voltage value. Controls which automatically
increase the voltage at a selectable rate are preferable.
A current-sensitive interrupting device shall be used for switching off the direct voltage source.
For many materials, a dangerous voltage may persist across the test specimen for a considerable
time after the d.c. test voltage is removed. Disconnection of the power supply to the direct
voltage source does not necessarily result in the output voltage or the voltage at the electrodes
being reduced to zero. For this reason, it is essential that the electrodes be short-circuited and
connected to earth for a period equal to minimum twice the total charging time to ensure that
the charge is dissipated. For some large test specimens, it will be necessary to maintain the
shorted condition for 1 h or even longer.
A current-limiting resistance shall be used in series with the test specimen to prevent damage
to the high-voltage supply and to limit as far as possible the damage to the electrodes on the
test specimen when breakdown takes place. The maximum current permitted will depend on
the material under test and on the amount of damage to the electrodes which can be tolerated.
NOTE 1: The use of a very high-valued resistor may result in breakdown voltages which are higher than
those obtained with a lower-valued resistor.
When making tests where the value or increase in the value of the current is used as a criterion
for breakdown, means of measurement of current through the test specimen shall be provided.
8.2 Voltage Measurement
The measurement of applied voltage shall be made across the electrodes. The other
requirements of Clause 8 of GB/T 1408.1-2016 shall be met.
9 Procedure
Clause 9 of GB/T 1408.1-2016 is applicable.
10 Mode of Increase of Voltage
Unless otherwise specified, the voltage shall be app...