外文翻譯---電力變壓器

1、<p><b>　　附錄</b></p><p>　　INTERNATIONAL STANDARD</p><p>　　POWER TRANSFORMERS</p><p>　　1. Scope and service conditions </p><p><b>　　1.1 Scope</b

2、></p><p>　　This part of international Standard IEC60076 applies to three-phase and single-phase power transformers (including auto-transformers) with the exception certain categories of small and special

3、transformers such as:</p><p>　　-single-phase transformers with rated power less than 1 KVA and three-phase transformers less than 5 KVA;</p><p>　　- instrument transformers;</p><p>　

4、　- transformers for static convertors;</p><p>　　-traction transformers mounted on rolling stock;</p><p>　　-starting transformers ;</p><p>　　-testing transformers ;</p><p&

5、gt;　　-welding transformers ;</p><p>　　When standards do not exist for such categories of transformers, this part may still be applicable either as a whole or in part.</p><p>　　1.2 Service condit

6、ions</p><p>　　This part gives detailed requirement for transformers for use under the following conditions:</p><p><b>　　Altitude </b></p><p>　　A height above sea-level n

7、ot exceeding 1000 m .</p><p>　　b) Temperature of ambient air not below - 25℃ and not above +40℃ .For water-cooled transformers , a temperature of cooling water at the inlet not exceeding +25℃ .</p>

8、<p>　　c) Wave shape of supply voltage</p><p>　　A supply voltage of which the wave shape is approximately sinusoidal.</p><p>　　NOTE This requirement is normally not critical in public suppl

9、y systems but may have to be considered in installations with considerable convertor loading in such cases there is a conventional rule that the deformation shall neither exceed 5 % total harmonic content nor 1 % even ha

10、rmonic content .Also note the importance of current harmonic for load loss and temperature rise.</p><p>　　d) Symmetry of three-phase supply voltage</p><p>　　For three-phase transformers, a set o

11、f three-phase supply voltage which are approximately symmetrical .</p><p>　　e) Installation environment </p><p>　　An environment with a pollution rate that does not require special consideration

12、 regarding the external insulation of transformer bushings or of the transformer itself.</p><p>　　An environment not exposed to seismic disturbance which would otherwise require special consideration in the

13、design. This is assumed to be the case when the ground acceleration level is below 2 m/s .</p><p>　　Provision for unusual service conditions</p><p>　　Any unusual service conditions which may lea

14、d to special consideration in the design of a transformer shall be stated in the enquiry and the order . These may be factors such as high altitude , extreme high or low temperature ,tropical humidity , seismic activity

15、, severe contamination , unusual voltage or load current wave shapes and intermittent loading . They may also concern conditions for shipment ,storage and installation , such as weight or space limitations.</p>&l

16、t;p>　　Supplementary rules for rating and testing are given in other publications for :</p><p>　　Temperature rise and cooling in high ambient temperature or at high altitude for oil-immersed transformers ,

17、 and for dry-transformers .</p><p>　　External insulation at high altitude :for oil-immersed transformers, and for dry-transformers.</p><p>　　2. Definitions </p><p>　　For the purpos

18、e of this part , the following definitions shall apply.</p><p>　　2.1 General</p><p>　　Power transformer </p><p>　　A static piece of apparatus with two or more winding , by electrom

19、agnetic induction , transformers a system of alternating voltage and current into another system of voltage and current usually of different values and at the same frequency for the purpose of transmitting electrical pow

20、er .</p><p>　　auto-transformer </p><p>　　a transformer of which at least two windings have a common part.</p><p>　　booster transformer </p><p>　　a transformer of which

21、one winding is intended to be connected in series with a circuit in order to alter its voltage and/or shift its phase . The other winding is an energizing winding.</p><p>　　Oil-immersed type transformer <

22、/p><p>　　a transformer of which the magnetic circuit and winding are immersed in oil.</p><p>　　NOTE For the purpose of this part any insulating liquid , mineral oil or other product , is regard as

23、oil .</p><p>　　dry-type transformer</p><p>　　a transformer of which the magnetic circuit and winding are not immersed in an insulating liquid .</p><p>　　oil preservation system</

24、p><p>　　the system in an oil-immersed transformer by which the thermal expansion of the oil is accommodated . Contact between the oil and external air may sometimes be diminished or prevented .</p><p

25、>　　2．2Terminals and neutral point </p><p><b>　　terminal</b></p><p>　　a conducting element intended for connecting a winding to external conductors</p><p>　　line termi

26、nal </p><p>　　a terminal intended for connecting to a line conductor of a network</p><p>　　neutral terminal</p><p>　　a) For three-phase transformers and three-phase banks of single-

27、phase transformers:</p><p>　　The terminal or terminals connected to the common point (the neutral point ) of a star-connected or zigzag connected winding .</p><p>　　For single-phase transformers

28、:</p><p>　　The terminal intended for connection to a neutral point of a network .</p><p>　　corresponding terminal </p><p>　　terminal of different windings of a transformer , marked

29、the same letter or corresponding symbol.</p><p>　　2.3Windings </p><p><b>　　winding </b></p><p>　　the assembly of turn forming an electrical circuit associated with one o

30、f the voltage assigned to the transformer.</p><p>　　NOTE For a three-phase transformer , the winding is the combination of the phase windings.</p><p>　　tapped winding </p><p>　　a w

31、inding in which the effective number of turns can be changed in steps</p><p>　　phase winding</p><p>　　the assembly of turns forming one phase of a three-phase winding</p><p>　　NOTE

32、 The term phase winding should not be used for identifying the assembly of all coil on a specific leg.</p><p>　　high-voltage winding</p><p>　　the winding having the highest rated voltage</p&g

33、t;<p>　　low-voltage winding</p><p>　　the winding having the lowest rated voltage</p><p>　　NOTE For a booster transformer , the winding having the lower rated voltage may be that having t

34、he higher insulation level.</p><p>　　intermediate-voltage winding</p><p>　　a winding of a multi-winding transformer having a rated voltage intermediate between the highest and lowest winding rat

35、ed voltages.</p><p>　　auxiliary winding</p><p>　　a winding intended only for a small load compared with the rated power of the transformer </p><p>　　stabilizing winding </p>

36、<p>　　a supplementary delta-connected winding provided in a star-star-connected or star-zigzag-connected transformer to decrease its zero-sequence impedance .</p><p>　　common winding</p><p>

37、;　　the common part of the winding of an auto-transformer.</p><p>　　series winding</p><p>　　the part of the winding of auto-transformer or the winding of a booster transformer which is intended t

38、o be connected in series with a circuit .</p><p>　　energizing winding </p><p>　　the winding of a booster transformer which is intended to supply power to the series winding.</p><p>

39、<b>　　2.4Rating</b></p><p><b>　　rating</b></p><p>　　those numerical values assigned to the quantities which define the operation of the transformer in the conditions speci

40、fied in this part and on which the manufacturer’s guarantees and the tests are based .</p><p>　　rated quantities</p><p>　　quantities(voltage ,current, etc ), the numerical values of which define

41、 the rating</p><p>　　NOTE 1 For transformers having tapping ,rated quantities are related to the principal tapping , unless otherwise specified . Corresponding quantities with analogous meaning , related to

42、other specific tapping , are called tapping quantities .</p><p>　　NOTE2 Voltage and current are always expressed by their r.m.s. values ,unless otherwise specified.</p><p>　　rated voltage of a

43、winding</p><p>　　the voltage assigned to be applied , or developed at no-load ,between the terminals of an untapped winding , or of a tapped winding connected on the principal tapping . For a three-phase wi

44、nding it is the voltage between line terminals .</p><p>　　NOTE1 The rated voltage of all windings appear simultaneously at no-load when the voltage applied to one of them has its rated value.</p><

45、;p>　　NOTE2 For single-phase transformers intended to be connected in star to form a three-phase bank, the rated voltage is indicated as phase-to-phase voltage ,divided by for example Ur=400kV.</p><p>　　

46、NOTE3 For the series winding of a three-phase booster transformer which is designed as an open winding , the rated voltage is indicated as if the winding were connected in star , for example Ur=23kV.</p><p>

47、;　　tapping , and that the temperature rise over ambient of any winding , at any tapping , does not exceed the specified maximum value .</p><p>　　rated voltage ratio</p><p>　　the ratio of the rat

48、ed voltage of a winding to the rated voltage of another winding associated with a lower or equal rated voltage .</p><p>　　rated frequency</p><p>　　the frequency at which the transformer is desig

49、ned to openrated .</p><p>　　rated power </p><p>　　a conventional value of apparent power assigned to a winding which ,together with the rated voltage of the winding , determines its rated curren

50、t.</p><p>　　NOTE1 Both winding of a two-winding transformer have the same rated power which by definition is the rated power of the whole transformer.</p><p>　　NOTE 2 For a multi-winding trans

51、former, half the arithmetic sum of the rated power values of all winding (separate winding , not auto-connected )gives a rough estimate of its physical size as compared with a two-winding transformer .</p><p&g

52、t;　　rated current </p><p>　　the current flowing through a line terminal of a winding which is derived from rated power Sr and rated voltage Ur for the winding .</p><p>　　NOTE For three-phase wi

53、nding the rated current Ir is given by:</p><p>　　Ir=Sr/Ur(A)</p><p>　　2.5Tapping</p><p><b>　　tapping</b></p><p>　　in a transformer having a tapped winding ,

54、 a specific connection of that winding, representing a definite effective number of turn in the tapped winding and ,consequently ,a definite turns ratio between this winding and other winding with fixed number of turns .

55、\</p><p>　　NOTE One of the tappings is the principal tapping , and other tappings are described in relation to the principal tapping by their respective tapping factors .</p><p>　　principal tap

56、ping</p><p>　　the tapping to which the rated quantities are related</p><p>　　tapping factor(corresponding to a given tapping )</p><p>　　The ratio: Ur/Ud(tapping factor ) or100Ur/Ud

57、( tapping factor expressed as a percentage )</p><p><b>　　Where </b></p><p>　　Ur is the rated voltage of the winding </p><p>　　Ud is the voltage which would be developed

58、at no-load at the terminals of the winding , at the tapping concerned , by applying rated voltage to an untapped winding.</p><p>　　NOTE This definition is not appropriate in relation to a series winding of a

59、 booster transformer , and in that case the percentage notation would be referred to the voltage of the energizing winding or of the winding of an associated system transformer .</p><p>　　plus tapping </p

60、><p>　　a tapping whose tapping factor is higher than 1.</p><p>　　minus tapping </p><p>　　a tapping whose tapping factor is lower than 1.</p><p>　　tapping step </p>

61、<p>　　the difference between the tapping factors ,expressed as a percentage , of two adjacent tapping .</p><p>　　tapping range</p><p>　　the variation range of the tapping factor ,expressed

62、as a percentage ,compared with the value 100</p><p>　　NOTE If this factor range from 100+a to 100-b , the tapping range is said to be :+a%, -b% or +a% ,if a=b.</p><p>　　tapping voltage ratio (of

63、 a pair of windings )</p><p>　　the ratio which is equal to the rated voltage ratio :</p><p>　　-multiplied by the tapping factor of the tapped winding if this is the high-voltage winding:</p

64、><p>　　-divided by the tapping factor of the tapped winding if this is the low-voltage winding.</p><p>　　NOTE While the rated voltage ratio is by definition, at least equal to 1 , the tapping volt

65、age ratio can be lower than 1 for certain tapping when the rated voltage ratio is close to 1.</p><p>　　tapping duty </p><p>　　the numerical values assigned to the quantities ,analogous to rated

66、quantities , which refer to tapping other than the principal tapping .</p><p>　　tapping quantities </p><p>　　those quantities the numerical values of which define the tapping duty of a particula

67、r tapping ( other than the principal tapping )</p><p>　　NOTE Tapping quantities exist for any winding in the transformer ,not only for the tapped winding .</p><p>　　The tapping quantities are ;&

68、lt;/p><p>　　-tapping voltage </p><p>　　-tapping power </p><p>　　-tapping current </p><p>　　.Requirements for transformers having a tapped winding </p><p>　　Ge

69、neral-Notation of tapping range</p><p>　　The following subclauses apply to transformers in which only one of the winding of the tapped winding.</p><p>　　In a multi-winding transformer,the state

70、ments apply to the combination of the tapped winding with either of the untapped windings.</p><p>　　In auto-connected transformers,tappings are sometimes arranged at the neutral which means that the effectiv

71、e number of turns is changed simultancously in both windings.For such transformers,the tapping particulars are subject to agreement.The requirement of this clause should be used as applicable.</p><p>　　Unles

72、s otherwise specified,the principal tapping is located in the middle of the tapping range.Other tappings are identified by their tapping factors.The number of tappings and the range of variation of the transformer ratio

73、may be expressed in short notation by the deviations of the tapping factor percentages from the value 100(for definitions of terms).</p><p>　　Example: A transformer with a tapped 160 kV winding having altoge

74、ther 21 tappings,symmetrically placed, is designateda:</p><p>　　(220±8×1.25%)/35 Kv</p><p>　　If for some reason the tapping range is specified asymmetrically around the rated voltage,w

75、e may get:</p><p>　　NOTE The way of short notation is only a description of the arrangement of the tapped winding and does not imply actual variations of applied voltage on that winding in service.This is de

76、alt with in 5.2 and 5.3.</p><p>　　Regarding the full presentation on the nameplate of data related to individual tappings.</p><p>　　Some tappings may be ‘reduced-power tappings’ due to restricti

77、ons in either tappings,voltage or tapping current.The boundary tappings where such limitations appear are called‘maximum voltage tapping’and ‘maximum current tapping’.</p><p>　　Tapping voltage-tapping curren

78、t, Standard categories of tapping voltage variation .Maximum voltage tapping.</p><p>　　The short notation of tapping range and tapping steps indicates the variation range of the ratio of the transformer, Bu

79、t the assigned values of tapping quantities are not fully defined by this alone .Additional information is necessary .This can be given either in tabular form with tapping power, tapping voltage and tapping current for e

80、ach tapping, or as text, indicating‘category of voltage variation’and possible limitations of the range with in which the tapping are ‘full-power tappings’ .</p><p>　　The extreme categories of tapping voltag

81、e variation are :</p><p>　　-constant flux voltage variation(CFVV),and</p><p>　　-variable flux voltage variation(VFVV).</p><p>　　They are defined as follows:</p><p><

82、b>　　CFVV</b></p><p>　　The tapping voltage in any untapped winding is constant from tapping to tapping .The tapping voltages in the tapped winding are proportional to the tapping factors.</p>

83、<p><b>　　VFVV</b></p><p>　　The tapping voltage in the tapped winding is constant from tapping to tapping. The tapping voltage in any untapped winding are inversely proportional to the tappin

84、g factor.</p><p><b>　　CbVV</b></p><p>　　In many application and particularly with transformers having a tapping range, a combination is specified using both principles applied to dif

85、ferent parts of the range: combined voltage variation(CbVV),The change-over point is called ‘maximum voltage tapping’.For this system the following applies:</p><p>　　CFVV applies for tapping with tapping fac

86、tors below the maximum voltage tapping factor.</p><p>　　VFVV applies for tapping with tapping factors above the maximum voltage tapping factor.</p><p>　　Tapping power .Full-power tappings-reduc

87、ed-power tappings</p><p>　　All tappings shall be full-power tappings,except as specified below.</p><p>　　In separate-winding transformers up to and including 2500kVA with a tapping range not exc

88、eeding ±5% the tapping current in the tapped winding shall be equal to rated current at all mius tappings.This means that the principal tapping is a ‘maximum current tapping ’,see below.</p><p>　　In tra

89、nsformers with a tapping range wider than ±5% ,restrictions may be specified on values of tapping voltage or tapping current which would otherwise rise considerably above the rated values.When such restrictions are

90、 specified ,the tappings concerned will be reuced-power tappings.This subclause describes such arrangements.</p><p>　　When the tapping factor deviates from unity, the tapping current for full-power tapping m

91、ay rise above rated current on one of the windings. In order to limit the corresponding reinforcement of the onwards the tapping current values for the winding are then specified to be constant . This means that the rema

92、ining tappings towards the extreme tapping are reduced-power tappings.</p><p>　　Under CbVV, the maximum voltage tapping , the change-over point between CFVV and VFVV shall at the same time be a maximum curre

93、nt tapping unless otherwise specified . This means thatthe untapped winding current stays constant up to the extreme plus tapping.</p><p>　　Specification of short-circuit Impedance</p><p>　　Unle

94、ss otherwise specified, the short-circuit impedance of a pair of windings is referred to the principal tapping .For transformers having a tapped winding with tapping range exceeding ±5% ,impedance values are also t

95、o be given for the two extreme tapping . On such transformers these three values of impedance shall also be measured during the short-circuit.</p><p>　　When impedance values are given for several tappings ,

96、and particularly when the winding of the pair have dissimilar rated power values , it is recommended that the impedance values be submitted in ohms per phase , referred to either of the windings , rather than as percenta

97、ge values . Percentage values may lead to confusion because of varying practices concerning reference values . Whenever percentage values are given it is advisable that the corresponding reference power and reference vol

98、tage </p><p>　　NOTE The selection of an impedance value by the user is subject to conflicting demands: limitation of voltage drop versus limitation of overcurrent under system fault conditions . Economic opt

99、imization of the design , bearing in mind loss , lead towards a certain range of impedance values . Parallel operation with an existing transformer .</p><p>　　If an enquiry contains a specification of not on

100、ly the impedance at the principal tapping but also its variation across the tapping range , this means a quite important restriction on the design (placing of winding in relation to each other ) . Such a detalled specif

101、ication should therefore not be issued without good reason.</p><p>　　A way of specifying short-circuit impedance values in the enquiry which leaves some degree of freedom in the design , is to indicate an a

102、cceptable range between upper and lower boundaries , across the whole tapping range . This may be done with the aid of a graph or a table .</p><p>　　The boundaries shall be at least as far apart as to permit

103、 the double-sided tolerances of clause to be applied on a median value between them . An example is shown in annex C . </p><p>　　The manufacturer shall select and guarantee impedance values for the principal

104、 tapping and for the extreme tapping which are between the boundaries . Measured values may deviate from guaranteed values within the tolerances according to clause , but shall not fall outside the boundaries , which are