1、Designation: D3382 13 An American National StandardStandard Test Methods forMeasurement of Energy and Integrated Charge Transfer Dueto Partial Discharges (Corona) Using Bridge Techniques1This standard is issued under the fixed designation D3382; the number immediately following the designation indic
2、ates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 These test methods cover two bridge techni
3、ques formeasuring the energy and integrated charge of pulse andpseudoglow partial discharges:1.2 Test Method A makes use of capacitance and losscharacteristics such as measured by the transformer ratio-armbridge or the high-voltage Schering bridge (Test MethodsD150). Test Method A can be used to obt
4、ain the integratedcharge transfer and energy loss due to partial discharges in adielectric from the measured increase in capacitance and tan with voltage. (See also IEEE 286 and IEEE 1434)1.3 Test Method B makes use of a somewhat differentbridge circuit, identified as a charge-voltage-trace (paralle
5、lo-gram) technique, which indicates directly on an oscilloscopethe integrated charge transfer and the magnitude of the energyloss due to partial discharges.1.4 Both test methods are intended to supplement themeasurement and detection of pulse-type partial discharges ascovered by Test Method D1868, b
6、y measuring the sum of bothpulse and pseudoglow discharges per cycle in terms of theircharge and energy.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and
7、health practices and determine the applica-bility of regulatory limitations prior to use. Specific precautionstatements are given in Section 7.2. Referenced Documents2.1 ASTM Standards:2D150 Test Methods for AC Loss Characteristics and Permit-tivity (Dielectric Constant) of Solid Electrical Insulati
8、onD1711 Terminology Relating to Electrical InsulationD1868 Test Method for Detection and Measurement ofPartial Discharge (Corona) Pulses in Evaluation of Insu-lation Systems2.2 IEEE Documents3IEEE 286 Recommended Practice for Measurement ofPower Factor and Power Factor Tip-up for RotatingMachine Sta
9、tor Coil InsulationIEEE 1434 Guide to the Measurement of Partial Dischargesin Rotating MachineryIEEE C57.113 Guide for PD Measurements in Liquid-FilledPower TransformersIEEE Standard C57.124 Recommended Practice for theDetection of PD and the Measurement ofApparent Chargein Dry-Type Transformers2.3
10、AEIC Documents4AEIC T-24-380 Guide for Partial Discharge ProcedureAEIC CS5-87 Specifications for Thermoplastic and Cross-linked Polyethylene Insulated Shielded Power CablesRated 5 through 35 kV, 9th Edition, 19873. Terminology3.1 Definitions:3.1.1 pseudoglow discharge, na type of partial discharge,w
11、hich takes place within an expanded discharge channel and ischaracterized by pulses of relatively low magnitude and longrise time.3.1.1.1 DiscussionPseudoglow discharges occur within adiffused discharge channel, whose emitted glow fills the entireintervening gap or cavity space (1). The discharge ra
12、te behav-ior as a function of applied voltage is similar to that of the rapidrise time pulse (spark-type) discharges. The successive pseudo-glow discharge pulses occur over the first quadrant of each halfcycle and in some gases, notably helium, their magnitude isfound to diminish to zero. At this po
13、int, a transition to apulseless glow discharge can occur. Its occurrence, which ismanifest by distortion in the sinusoidal voltage wave, is rare.1These test methods are under the jurisdiction of ASTM Committee D09 onElectrical and Electronic Insulating Materials and are the direct responsibility ofS
14、ubcommittee D09.12 on Electrical Tests.Current edition approved Nov. 1, 2013. Published December 2013. Originallyapproved in 1975. Last previous edition approved in 2007 as D3382 07. DOI:10.1520/D3382-13.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Se
15、rvice at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from Institute of Electrical and Electronics Engineers, Inc. (IEEE),445 Hoes Ln., P.O. Box 1331, Piscataway, NJ 08854-1331, http:/www.ieee.org.4Av
16、ailable from The Association of Edison Illuminating Companies (AEIC),600 N. 18th St, Birmingham, AL 35291, www.aeic.org.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1A
17、t discharge inception of a single cavity, the pattern ofpseudoglow discharges consists of a single long rise timedischarge current pulse in each half-cycle. It has becomecommon practice to refer to this particular type of pattern asthat of a glow discharge.Pseudoglow partial discharges, which occur
18、at low gaspressures, such as in insulating systems of electrical equipmentfor aerospace applications, have unduly long rise times and afrequency spectrum that falls bellow the bandwidth of conven-tional partial discharge pulse detectors (2). As a consequence,they cannot be detected by the partial di
19、scharge detectorsspecified in Test Method D1868; however they can be detectedand measured by either MethodAor B ofTest Methods D3382.3.1.2 pulse discharge, na type of partial-discharge phe-nomenon characterized by a spark-type breakdown whichoccurs in a narrow constricted channel.3.1.2.1 DiscussionT
20、he resultant detected pulse dischargehas a short rise time and its Fourier frequency spectrum mayextend as far as 1 GHz. Such a pulse discharge may be readilydetected by conventional pulse detectors, that are generallydesigned for partial-discharge measurements within the fre-quency band from 30 kHz
21、 to several megahertz. (See alsoIEEE 1434, IEEE C57.113, IEEE C57.124, AEIC T-24-380,and AEIC CS5-87.)3.1.3 pulseless-glow discharge, nan uncommon type ofpartial discharge , whose existence is manifest not by the usualabrupt voltage fall discontinuities in the sinusoidal voltagewave at each discharg
22、e epoch but rather by distortions in thewaveform.3.1.3.1 DiscussionIt is generally found that the pulselessglow region develops only when preceded by a pseudoglowdischarge in which the abrupt voltage collapse magnitudes ateach discharge have gradually diminished in the limit to zero.The nature of th
23、is pulseless glow region is not fullyunderstood, but it is believed to consist of a very weaklyionized gas volume. Further increases in the applied voltagecan lead to more complex partial discharge patterns, consistingof regions of pseudoglow, pulseless and pulse type discharges(3). Pulse type parti
24、al discharge detectors of the type describedin Test Method D1868 cannot be employed to detect pulselessglow discharges.3.1.4 See (1) and (3) for more information on the previousdefinitions.3.1.5 For definitions of other terms pertaining to this stan-dard refer to Terminology D1711.3.2 Symbols:3.2.1
25、Refer to Annex A1 for symbols for mathematicalterms used in this standard.4. Summary of Test Methods4.1 It is possible to represent the dielectric characteristics ofa specimen of solid insulating material by a parallel combina-tion of capacitance and conductance. The values of capacitanceand conduct
26、ance remain practically constant over the usefulrange of alternating voltage stress at a fixed frequency. If,however, the specimen contains gaseous inclusions (cavities),incremental increases in capacitance and conductance occur asthe voltage stress is raised above the value necessary to initiatepar
27、tial discharges in the cavities. The energy loss in theincremental conductance is considered to be that dissipated bythe partial discharges.4.2 In Test Method A an initial measurement is made of thecapacitance and loss characteristic of the specimen at anapplied voltage below the discharge inception
28、 level. Thevoltage is then raised to the specified test value and a secondmeasurement made.The energy loss due to partial discharges iscalculated from the results of the two measurements.4.3 In Test Method B a special bridge circuit is balanced ata voltage below the discharge inception level. The vo
29、ltage isthen raised to the specified test value, but the bridge is notrebalanced.Any unbalanced voltage at the detector terminals isdisplayed in conjunction with the test voltage on an oscillo-scope. The oscilloscope pattern approximates a parallelogram,the area of which is a measure of the energy l
30、oss due to partialdischarges.5. Significance and Use5.1 These test methods are useful in research and qualitycontrol for evaluating insulating materials and systems sincethey provide for the measurement of charge transfer and energyloss due to partial discharges(4)(5)(6).5.2 Pulse measurements of pa
31、rtial discharges indicate themagnitude of individual discharges. However, if there arenumerous discharges per cycle it is occasionally important toknow their charge sum, since this sum can be related to thetotal volume of internal gas spaces that are discharging, if it isassumed that the gas cavitie
32、s are simple capacitances in serieswith the capacitances of the solid dielectrics (7)(8).5.3 Internal (cavity-type) discharges are mainly of the pulse(spark-type) with rapid rise times or the pseudoglow-type withlong rise times, depending upon the discharge governingparameters existing within the ca
33、vity. If the rise times of thepseudoglow discharges are too long , they will evade detectionby pulse detectors as covered in Test Method D1868. However,both the pseudoglow discharges irrespective of the length oftheir rise time as well as pulseless glow can be readilymeasured either by Method A or B
34、 of Test Methods D3382.5.4 Pseudoglow discharges have been observed to occur inair, particularly when a partially conducting surface is in-volved. It is possible that such partially conducting surfaceswill develop with polymers that are exposed to partial dis-charges for sufficiently long periods to
35、 accumulate acidicdegradation products. Also in some applications, liketurbogenerators, where a low molecular weight gas such ashydrogen is used as a coolant, it is possible that pseudoglowdischarges will develop.6. Sources of Errors6.1 Surface DischargesAll discharges in the test specimenare measur
36、ed, whether on the surface or in internal cavities. Ifit is desired to measure only internal cavities, the otherdischarges must be avoided. In the case of an insulatedconductor with an outer electrode on the surface (such as acable or generator coil), the surface discharges at the end of thisouter e
37、lectrode can be removed from the measurement with aD3382 132closely-spaced guard ring connected to ground. See Section 4of Test Methods D150.6.2 Since tests will be made at ionizing voltage, all connec-tions making up the complete high-voltage circuit should befree of corona to avoid measurement int
38、erference. See Section5 of Test Method D1868.6.3 Anomalous changes in insulation losses with changes involtage stress can occur as a result of phenomena other thanpartial discharges. Such losses are a source of error in thesemethods, since they are indistinguishable from dischargelosses. However, th
39、ese losses are often negligible in compari-son with partial discharge losses.6.4 It is possible that any temperature change in the speci-men between the times at which the low-voltage and high-voltage measurements are taken will cause a change in thenormal losses and appear as changes in discharge e
40、nergy, thuscausing an error in test results. This situation can be recognizedin Method B and corrective action taken (see 11.3).6.5 Paint used to grade potential on the surface of someinsulation specimens (for example, generator stator coil) shallnot be included in the measurement, since it is possi
41、ble that theconductance of such paints will change with voltage and affectthe accuracy of the method as a measure of discharge energy.It is sometimes possible to exclude the painted surfaces fromthe measuring circuit by the use of guarding or shieldingtechniques.7. Hazards7.1 Warning It is possible
42、that lethal voltages will bepresent during this test. It is essential that the test apparatus,and all associated equipment potentially electrically connectedto it, be properly designed and installed for safe operation.Solidly ground all electrically conductive parts that any personmight come in cont
43、act with during the test. Provide means foruse at the completion of any test to ground any parts which:were at high voltage during the test; have the potential to haveacquired an induced charge during the test; have the potentialto retain a charge even after disconnection of the voltagesource. Thoro
44、ughly instruct all operators in the proper way toconduct tests safely. When making high voltage tests, particu-larly in compressed gas or in oil, it is possible that the energyreleased at breakdown will be suffcient to result in fire,explosion, or rupture of the test chamber. Design of testequipment
45、, test chambers, and test specimens shall be such asto minimize the possibility of such occurrences and to eliminatethe possibility of personal injury.7.2 Warning Ozone is a physiologically hazardous gas atelevated concentrations. The exposure limits are set by gov-ernmental agencies and are usually
46、 based upon recommenda-tions made by the American Conference of GovernmentalIndustrial Hygienists.5Ozone is likely to be present whenevervoltages exist which are sufficient to cause partial, or complete,discharges in air or other atmospheres that contain oxygen.Ozone has a distinctive odor which is
47、initially discernible atlow concentrations but sustained inhalation of ozone can causetemporary loss of sensitivity to the scent of ozone. Because ofthis it is important to measure the concentration of ozone in theatmosphere, using commercially available monitoring devices,whenever the odor of ozone
48、 is persistently present or whenozone generating conditions continue. Use appropriate means,such as exhaust vents, to reduce ozone concentrations toacceptable levels in working areas.TEST METHOD A8. Procedure8.1 Conventional circuits for the measurement ofalternating-voltage capacitance and loss cha
49、racteristics of in-sulation can be used for this method. The transformer-ratioarmbridge shown in Fig. 1, or the Schering bridge shown inFig. X4.2 of Test Methods D150 are well suited to thisapplication.8.2 Energize the test specimen at a low voltage, V1, belowthe discharge-inception voltage, and measure capacitance Cx1and dissipation factor tan 1. Raise the voltage to a specifiedtest level, V2, and repeat the measurements for Cx2and tan 2.Calculate the power loss, P, in watts due to discharges atvoltage V2as follows:P 5 V22Cx2tan 22 Cx1tan 1! (1)5P22P1V22/V12!(2
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