Cart (0)
  • No items in cart.
Total
$0
There is a technical issue about last added item. You can click "Report to us" button to let us know and we resolve the issue and return back to you or you can continue without last item via click to continue button.
Search book title
Filters:
FORMAT
BOOKS
PACKAGES
EDITION
to
PUBLISHER
(1)
(338)
(589)
(599)
(55)
(234)
(1006)
(696)
(2183)
(117)
(95207)
(63)
(575)
(124)
(33)
(21)
(20)
(95735)
(3)
(17)
(1)
(374)
(324)
(6938)
(241)
(21)
(6)
(1667)
(17)
(19)
(28)
(4)
 
(6)
(7)
(115)
(3)
(57)
(5)
(5)
(1)
(1)
(2)
(25)
(27)
(27)
(13)
(61)
(24)
(22)
(7)
(8)
(20)
(1)
(3)
(50)
(6)
(33)
CONTENT TYPE
 Act
 Admin Code
 Announcements
 Bill
 Book
 CADD File
 CAN
 CEU
 Charter
 Checklist
 City Code
 Code
 Commentary
 Comprehensive Plan
 Conference Paper
 County Code
 Course
 DHS Documents
 Document
 Errata
 Executive Regulation
 Federal Guideline
 Firm Content
 Guideline
 Handbook
 Interpretation
 Journal
 Land Use and Development
 Law
 Legislative Rule
 Local Amendment
 Local Code
 Local Document
 Local Regulation
 Local Standards
 Manual
 Model Code
 Model Standard
 Notice
 Ordinance
 Other
 Paperback
 PASS
 Periodicals
 PIN
 Plan
 Policy
 Product
 Product - Data Sheet
 Program
 Provisions
 Requirements
 Revisions
 Rules & Regulations
 Standards
 State Amendment
 State Code
 State Manual
 State Plan
 State Standards
 Statute
 Study Guide
 Supplement
 Sustainability
 Technical Bulletin
 All
  • ASTM
    D2275-01(2008)e1 Standard Test Method for Voltage Endurance of Solid Electrical Insulating Materials Subjected to Partial Discharges (Corona) on the Surface
    Edition: 2008
    $103.58
    Unlimited Users per year

Description of ASTM-D2275 2008

ASTM D2275 - 01(2008)e1

Standard Test Method for Voltage Endurance of Solid Electrical Insulating Materials Subjected to Partial Discharges (Corona) on the Surface

Active Standard ASTM D2275 | Developed by Subcommittee: D09.12

Book of Standards Volume: 10.01




ASTM D2275

Significance and Use

This test method is used to compare the endurance of different materials to the action of corona on the external surfaces. A poor result on this test does not indicate that the material is a poor selection for use at high voltage or at high voltage stress in the absence of surface corona. Surface corona should be distinguished from corona that occurs in internal cavities for which no standardized test has been developed. Evaluation of endurance by comparison of data on specimens of different thickness is not valid.

The processing of the material may affect the results obtained. For instance, residual strains produced by quenching, or high levels of crystallinity caused by slow cooling may affect the result. Also, the type of molding process, injection or compression, may be important especially if the mixing of fillers or the concentration and sizes of gas-filled cavities are controlled in any degree by the process. Indeed, this test method may be used to examine the effects of processing.

The data are generated in the form of a set of values of lifetimes at a voltage. The dispersion of failure times can be analyzed using Weibull or extreme value statistics to yield an estimate of the central value of the distribution and its standard deviation. This is particularly recommended when the dispersion of failure times is large, and a comparison of lifetimes of two materials must be made at a specified level of confidence.

This test is often used to demonstrate the differences between different classes of materials, and to illustrate the importance of eliminating corona in any application of a particular material. When the test is used for such purposes or other similar ones, the need for precision is reduced, and certain time saving techniques, such as truncating a test at the time of the fifth failure of a set of nine, and using that time as the measure of the central tendency, are recommended. Two such techniques are described in 10.2. Both techniques remove the necessity of testing beyond median failure, and reduce the required testing time to approximately half of that required to obtain failures on all specimens.

Insulating materials operating in a gaseous medium are subjected to corona attack at operating voltage on some types of electrical apparatus in those regions where the voltage gradient in the gas exceeds the corona inception level. On other types of equipment, where detectable corona is absent initially, it may appear later due to transient over-voltages or changes in insulation properties attending aging. Certain inorganic materials can tolerate corona for a long time. Many organic materials are damaged quickly by corona, and for these, operation with no detectable corona is imperative. This test method intensifies some of the more commonly met conditions of corona attack so that materials may be evaluated in a time that is relatively short compared to the life of the equipment. As with most accelerated life tests, caution is necessary in extrapolation from the indicated life to actual life under various operating conditions in the field.

The failure produced by corona may be due to one of several possible factors. The corona may erode the insulation until the remaining insulation can no longer withstand the applied voltage. The corona may cause the insulation surface to become conducting. For instance, carbonization may occur, so that failure occurs quickly. On the other hand, compounds such as oxalic acid crystals may be formed, as with polyethylene, in which case the surface conductance will vary with ambient humidity, and at moderate humidities the conductance may be at the proper level to reduce the potential gradient at the electrode edge, and thus cause either a reduction in the amount of corona, or its cessation, thus retarding failure. The corona may cause a treeing within the insulation, which may progress to failure. It may release gases within the insulation that change its physical dimensions. It may change the physical properties of an insulating material; for instance, it may cause the material to embrittle or crack, and thus make it useless.

Tests are often made in open air, at 50 % relative humidity. It may be important for some materials to make tests in circulating air at 20 % relative humidity or less (see Appendix X1). If tests are made in an enclosure, the restriction in the flow of air or other gas may influence the results (see Appendix X2).

The shape of the (voltage stress)-(time-to-failure) curve is sometimes useful as an indicator of the useable electric strength of a material in an application involving surface corona and its variation with time of application of voltage, though such comparisons are risky. (Specimen thickness, electrode system, the presence of more than one mechanism of failure, and the details of the ambient, including the nature of the surface corona, all have significant effects.) For instance, on log-log paper, the volt-time curve often obtained by the procedures of this test for void-free materials such as polyethylene sheet generally has a continuous curvature that is slightly concave upward. The low voltage end of the curve tends toward the horizontal and approaches a threshold voltage below which the curve does not go. A similar threshold would be expected for many materials in an application involving surface corona. Moreover, if the material possesses a low electric strength (as measured by Test Method D 149 ), or especially if in service there is another mechanism of failure in the short time range of this test, the shape of the left hand end of the curve would be affected and would not reach the same high levels of stress as are exhibited by polyethylene either on this test or in many service applications, including surface corona. In summary, voltage stress-time curves are useful tools for examining modes and mechanisms of failure, but must be used with care.

For materials that possess a basic resistance to corona, such as mica, or, to a smaller degree, silicone rubber, the time required for the curve to reach the threshold produced by corona may be greater by many orders of magnitude than the time required for materials such as polyethylene, polyethylene terephthalate, or polytetrafluoroethylene.

The variability of the time to failure is a function of the constancy of the parameters of the test, such as the test voltages, which should be monitored. It is also a significant material property. The Weibull slope factor, ? , is recommended as a measure of variability. ? is the slope obtained when percent failure is plotted against failure time on Weibull probability paper. Such a plot is called a Weibull probability plot (see Fig. 1).

The shape of the Weibull probability plot can provide additional information. A non-straight-line plot may indicate more than one mechanism of failure. For instance, a few unaccountably short time failures in the set could indicate a small portion of defective specimens with a different failure mechanism from the rest of the lot.

1. Scope

1.1 This test method differentiates among solid electrical insulating materials for use at commercial power frequencies with respect to their voltage endurance under the action of corona (see Note 1). In general, this test method is more meaningful for rating materials with respect to their resistance to prolonged a-c stress under corona conditions than is dielectric strength.

Note 1The term corona is used almost exclusively in this test method instead of partial discharge , because it is a visible glow at the edge of the smaller electrode. This is a difference in location, not in kind. Partial discharges also occur at the edges of electrodes, and in general corona describes an electrical discharge irrespective of its location.

1.2 The values stated in SI units are to be regarded as standard. The values given in parentheses are mathematical conversions to inch-pound units that are provided for information only and are not considered standard.

1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see Section 7.


2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

ASTM Standards

D149 Test Method for Dielectric Breakdown Voltage and Dielectric Strength of Solid Electrical Insulating Materials at Commercial Power Frequencies

D1711 Terminology Relating to Electrical Insulation

D1868 Test Method for Detection and Measurement of Partial Discharge (Corona) Pulses in Evaluation of Insulation Systems

D5032 Practice for Maintaining Constant Relative Humidity by Means of Aqueous Glycerin Solutions

D6054 Practice for Conditioning Electrical Insulating Materials for Testing

E41 Terminology Relating To Conditioning

E104 Practice for Maintaining Constant Relative Humidity by Means of Aqueous Solutions

E171 Practice for Conditioning and Testing Flexible Barrier Packaging

Institute of Electrical and Electronic Engineers (IEEE) Document

IEEE SS 11205-TBR Guide for the Statistical Analysis of Electrical Insulation Voltage Endurance Data, 1987 Available from Institute of Electrical and Electronics Engineers, Inc. (IEEE), 445 Hoes Ln., P.O. Box 1331, Piscataway, NJ 08854-1331, http://www.ieee.org.

International Electrotechnical Commission (IEC) Documents

IEC Publication 6034 Recommended test methods for determining the relative resistance of insulating materials to breakdown by surface discharges Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http://www.ansi.org.

Special Technical Publications

Corona Measurement a ASTM, 1979.

Keywords

partial discharge; surface discharge; threshold voltage; voltage indurance; voltage stress time curve; volt time curve; Corona; Electrical insulating solids; Electrical properties; Surface discharges (corona); Voltage;


ICS Code

ICS Number Code 29.035.01 (Insulating materials in general)


DOI: 10.1520/D2275-01R08E01

ASTM International is a member of CrossRef.

ASTM D2275

This book also exists in the following packages...

Year Publisher Title Annual Price
VAR
ASTM
[+] $759.66 Buy
VAR
ASTM
[+] $2,452.26 Buy
VAR
ASTM
[+] $3,738.90 Buy

Subscription Information

MADCAD.com ASTM Standards subscriptions are annual and access is unlimited concurrency based (number of people that can access the subscription at any given time) from single office location. For pricing on multiple office location ASTM Standards Subscriptions, please contact us at info@madcad.com or +1 800.798.9296.

 

Some features of MADCAD.com ASTM Standards Subscriptions are:

- Online access: With MADCAD.com’ s web based subscription service no downloads or installations are required. Access ASTM Standards from any browser on your computer, tablet or smart phone.

- Immediate Access: As soon as the transaction is completed, your ASTM Standards Subscription will be ready for access.

 

For any further information on MADCAD.com ASTM Standards Subscriptions, please contact us at info@madcad.com or +1 800.798.9296.

 

About ASTM

ASTM International, formerly known as the American Society for Testing and Materials (ASTM), is a globally recognized leader in the development and delivery of international voluntary consensus standards. Today, some 12,000 ASTM standards are used around the world to improve product quality, enhance safety, facilitate market access and trade, and build consumer confidence. ASTM’s leadership in international standards development is driven by the contributions of its members: more than 30,000 of the world’s top technical experts and business professionals representing 150 countries. Working in an open and transparent process and using ASTM’s advanced electronic infrastructure, ASTM members deliver the test methods, specifications, guides, and practices that support industries and governments worldwide.

X