1、BRITISH STANDARDBS EN 60609-2:1999Incorporating Corrigendum No. 1 and Amendment No. 1 to BS IEC 60609-2:1997 (renumbers the BS as BS EN 60609-2:1999)Cavitation pitting evaluation in hydraulic turbines, storage pumps and pump turbines Part 2: Evaluation in Pelton turbinesICS 27.140BS EN 60609-2:1999T
2、his British Standard, having been prepared under the direction of the Engineering Sector Board, was published under the authority of the Standards Board and comes into effect on 15 February 1998 BSI 2006ISBN 0 580 29226 6National forewordThis British Standard reproduces verbatim IEC 60609-2:1997 and
3、 implements it as the UK national standard.The UK participation in its preparation was entrusted to Technical Committee MCE/15, Hydraulic turbines, which has the responsibility to: aid enquirers to understand the text; present to the responsible international/ European committee any enquiries on the
4、 interpretation, or proposals for change, and keep UK interests informed; monitor related international and European developments and promulgate them in the UK.A list of organizations represented on this committee can be obtained on request to its secretary.Cross-referencesThe British Standards whic
5、h implement international or European publications referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online.This publicati
6、on does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard
7、 does not of itself confer immunity from legal obligations.Summary of pagesThis document comprises a front cover, an inside front cover, the EN title page, the EN foreword page, pages i and ii, the IEC title page, pages ii to iv, pages 1 to 10, Annex ZA and a back cover.This standard has been update
8、d (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.Amendments issued since publicationAmd. No. Date Comments9968 Corrigendum No.1March 1998 Title on front cover15739 Amendment No. 128 April 2006 EN title page, EN f
9、oreword and Annex ZABSEN 60609-2:1999 BSI 2006 iContentsPageNational foreword Inside front coverForeword iiiText of CEI IEC60609-2 1ii blankBSEN 60609-2:1997ii BSI 2006ContentsPageForeword iiiIntroduction 11 General 11.1 Scope and object 11.2 Excluded topics 11.3 Normative reference 22 Terms, symbol
10、s and definitions 22.1 Units 22.2 List of terms 22.3 Location and type of damage to Pelton buckets 43 Nature and extent of cavitation pitting guarantees 53.1 Period of guarantee 53.2 Definition of the amount of cavitation pitting 53.3 Operating ranges and duration of operation 63.3.1 Reference durat
11、ion of operation 63.3.2 Actual duration of operation 63.3.3 Special conditions 64 Test procedure 64.1 Cavitation pitting repair during the guarantee period 64.2 Measurement and calculation of the amount of cavitation pitting 75 Computation of results 75.1 Fulfilment of the guarantee 7Annex A (normat
12、ive) Examples of amounts of cavitation pittings 8Annex B (informative) Bibliography 10Annex ZA (normative) Normative references to international publicationswith their corresponding European publications 11 Figure 1 Operating ranges 4Figure 2 Location of damage due to cavitation pitting 5Figure A.1
13、Examples of maximum permissible valuesof cavitation pitting on a Pelton runner(for the reference duration of 8000h 9BSEN 60609-2:1997 BSI 2006 iiiForeword1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprising all national electrotechnical co
14、mmittees (IEC National Committees). The object of the IEC is to promote international co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and in addition to other activities, the IEC publishes International Standards. Their preparation is ent
15、rusted to technical committees; any IEC National Committee interested in the subject dealt with may participate in this preparatory work. International, governmental and non-governmental organizations liaising with the IEC also participate in this preparation. The IEC collaborates closely with the I
16、nternational Organization for Standardization (ISO) in accordance with conditions determined by agreement between the two organizations.2) The formal decisions or agreements of the IEC on technical matters express, as nearly as possible, an international consensus of opinion on the relevant subjects
17、 since each technical committee has representation from all interested National Committees.3) The documents produced have the form of recommendations for international use and are published in the form of standards, technical reports or guides and they are accepted by the National Committees in that
18、 sense.4) In order to promote international unification, IEC National Committees undertake to apply IEC International Standards transparently to the maximum extent possible in their national and regional standards. Any divergence between the IEC Standard and the corresponding national or regional st
19、andard shall be clearly indicated in the latter.5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any equipment declared to be in conformity with one of its standards.6) Attention is drawn to the possibility that some of the elements of this Int
20、ernational Standard may be the subject of patent rights. The IEC shall not be held responsible for identifying any or all such patent rights.International Standard IEC60609-2 has been prepared by IEC technical committee 4: Hydraulic turbines.The text of this standard is based on the following docume
21、nts:Full information on the voting for the approval of this standard can be found in the report of voting indicated in the above table.Annex A forms an integral part of this standard.Annex B is for information only.FDIS Report on voting4/127/FDIS 4/139/RVDiv blankBSEN 60609-2:1997 BSI 2006 1Introduc
22、tionIEC 60609 (1978) treats cavitation pitting in reaction machines but does not refer to Pelton (impulse) turbines. Appendix A of IEC60609 states that Pelton turbines “usually are not subjected to cavitation pitting”.However, experience shows that with increase of specific speed (especially of mult
23、ijet turbines) and of specific hydraulic energy (head) the probability of cavitation pitting and drop erosion on Pelton turbines increases. Consequently weight loss guarantees on Pelton turbines may be required.Various types of damage are observed, each the result of different flow phenomena, such a
24、s pitting due to: profile errors; unfavourable inflow conditions; erosion due to travelling droplets (drop erosion, also called jet impingement);and in some instances setting conditions (e.g.setting of the runner referred to the tailwater level, or tailwater depression).The causes of damage are ofte
25、n complex and have to be carefully investigated, taking into account also conditions which are excluded in the cavitation guarantee (see1.2). However it is not the objective of this part of IEC60609 to describe the requirements and measures needed for avoiding cavitation pitting due to hydraulic sha
26、pe and surface roughness of turbine parts (buckets, nozzles, etc.), or installation requirements (setting, inflow conditions).Those requirements are part of the know-how of the turbine contractor.The damage (i.e.pitting respective weight loss) due to these various causes (cavitation pitting and drop
27、 erosion) is combined in the following clauses as the term “cavitation pitting”.1 General1.1 Scope and objectThis part of IEC 60609 serves as a basis for the formulation of guarantees on cavitation pitting on Pelton turbine runners and also for the measurement and evaluation of the amount of cavitat
28、ion pitting on Pelton turbine runners of a given turbine, which is defined in the contract by power, specific hydraulic energy of machine (head), rotational speed, material, operation, etc.The sequence of clauses in this part of IEC 60609 is the same as in IEC 60609 (1978). The clauses on measuremen
29、ts and evaluation of the amount of cavitation pitting are practically identical to those of IEC60609. Evaluation has to be based on the loss of material during a given time and under accurately defined operating conditions.Guarantees which restrict the extent of cavitation pitting and drop erosion o
30、n Pelton turbines at the end of an operating period specified in the contract are necessary when cavitation pitting is expected in all or in some operating ranges. Such guarantees should include limits for operation which are consistent with specified operating conditions.1.2 Excluded topicsIt is as
31、sumed in this part of IEC 60609 that the water is not chemically aggressive to a significant degree and that it is essentially free from abrasive solids.The cavitation guarantee shall, however, be given on the basis of an agreed water analysis. If it becomes apparent in the course of later analysis
32、that the water is in fact more aggressive than the agreed analysis indicated, this shall be taken into consideration when judging whether the given guarantees have been met.In case of a distorted inflow condition at the inlet of the turbine due to irregularities upstream of the turbine, hydraulic ef
33、fects may be raised, which beyond the influence on hydraulic performance also may cause cavitation pitting. Therefore it is claimed for the basis of cavitation pitting guarantees that a satisfactorily uniform and vortex-free flow condition shall be provided. In case of damage, the influence of impro
34、per inflow condition shall be taken into account.BSEN 60609-2:19972 BSI 2006Abrasion due to water contaminated with solids (e.g.sand) cannot be considered as cavitation pitting. The solids content of the water and also if relevant the type of minerals and size and form of solid (sand) particles shal
35、l be stated in the water analysis and, if it reaches significant proportion, shall be the subject of a special agreement. Aspects of abrasive wear by sand erosion are dealt with in IEC61366 (Annex H).Abrasion may cause a change of the geometry of the needle and/or the bucket and subsequently cavitat
36、ion pitting as secondary damage. Such damage shall be excluded from the evaluation of cavitation.If cavitation pitting occurs in zones where damage can be separately attributable to abnormal chemical or electrochemical corrosion, abrasion or mechanical impact, such damage shall be excluded from the
37、evaluation of cavitation.If cavitation pitting occurs in zones where damage can be shown to have been increased by chemical or electrochemical effects additional to those normal to cavitation in water of the agreed analysis, then such zones shall be excluded from the evaluation of cavitation.In this
38、 context, attention should be paid to the material selection in reference to abrasion by sand erosion and/or chemical or electrochemical corrosion.Material defects revealed by wear on the machine surfaces during operation are not taken into account to verify a guarantee against cavitation pitting.Sp
39、ecial operating conditions such as discharging by means of deflector or cut-in deflector shall be excluded from cavitation pitting guarantees.1.3 Normative referenceThe following normative document contains provisions which, through reference in this text, constitute provisions of this part of IEC 6
40、0609. At the time of publication, the edition indicated was valid. All normative documents are subject to revision, and parties to agreements based on this part of IEC 60609 are encouraged to investigate the possibility of applying the most recent edition of the normative document indicated below. M
41、embers of IEC and ISO maintain registers of currently valid International Standards.IEC 60609:1978, Cavitation pitting evaluation in hydraulic turbines, storage pumps andpump-turbines. 2 Terms, symbols and definitions2.1 UnitsThe International System of units (SI) has been used in this part of IEC 6
42、0609. Dimensions for pitting are given in centimetres.2.2 List of termsThe terms, symbols and definitions adopted in this part of IEC 60609 are listed below1):1) They are also based, where relevent, on IEC 61364.2.2.1 cavitation Vapour bubbles which form when the level of local pressure drops to app
43、roximately that of vapour pressure and which collapse when the level of local pressure rises above that of vapour pressure.2.2.2 cavitation pitting Loss of material caused by cavitation.2.2.3 drop erosion Loss of material caused by impact of travelling droplets (liquid impact erosion, jet impingemen
44、t).2.2.4 abrasion Loss of material caused by suspended solids (e.g.sand) eroding the material surface (abrasive wear, sand erosion).2.2.5 cavitation guarantee Number of months or years of service of a machine during which the period cavitation pitting guarantee is valid.2.2.6 cavitation guarantee du
45、ration of operation Number of machine operating hours during which the cavitation pitting guarantee is valid.BSEN 60609-2:1997 BSI 2006 32.2.7 reference duration of operation tR (h) Number of machine operating hours used as a reference value for establishing cavitation pitting guarantees.2.2.8 actua
46、l duration of operation tA (h) The actual number of machine operating hours at the time of cavitation pitting examination.2.2.9 E (Jkg1) Specific hydraulic energy of machine (turbine), E = gH, see2.2.11 andb.2.2.10 g (ms2) Acceleration due to gravitya.2.2.11 H (m) Head of turbine H = E/g.2.2.12 P (W
47、) Power, mechanical power of the turbine.2.2.13 PCU Upper power limit for normal continuous operation specified for each specific hydraulic energy(see Figure 1).2.2.14 PTU Upper power limit for temporary abnormal operation specified for each specific hydraulic energy (seeFigure 1).2.2.15 PCL Lower p
48、ower limit for normal continuous operation specified for each specific hydraulic energyc (seeFigure 1).2.2.16 Continuous normal operating rangeLimited by PCU and PCL (seeFigure 1).2.2.17 High turbine load temporary abnormal operating rangeLimited by PCU and PTU (seeFigure 1).2.2.18 S (cm) The absolu
49、te maximum depth of any pitted area measured from the original surface; for further explanation see also2.3; (guaranteed maximum depth=Smax)2.2.19 S1, S2, S3, etc. The maximum depth of a particular pitted area measured from the original surface.2.2.20 A (cm2) Total area of the whole runner damaged by cavitation pitting: inside of bucket (location3, 4, 5 and 6 of Figure 2), outside of bucket in the range of back of splitter and cut-out (location1, 1
