IEC 61400-12-6:2022 specifies a procedure for measuring the nacelle transfer function of a single electricity-producing, horizontal axis wind turbine, which is not considered to be a small wind turbine in accordance with IEC 61400-2. It is expected that this document be used when a valid nacelle transfer function is needed to execute a power performance measurement according to IEC 61400-12-2. This document specifies how to characterise a wind turbine’s nacelle transfer function. The nacelle transfer function is determined by collecting simultaneous measurements of nacelle\u2011measured wind speed and free stream wind speed (as measured on a meteorological mast) for a period that is long enough to establish a statistically significant database over a range of wind speeds and under varying wind and atmospheric conditions. The procedure also provides guidance on determination of measurement uncertainty including assessment of uncertainty sources and recommendations for combining them. This first edition of IEC 61400-12-6 is part of a structural revision that cancels and replaces the performance standards IEC 61400-12-1:2017 and IEC 61400-12-2:2013. The structural revision contains no technical changes with respect to IEC 61400-12-1:2017 and IEC 61400\u201112\u20112:2013, but the parts that relate to wind measurements, measurement of site calibration and assessment of obstacle and terrain have been extracted into separate standards.<\/p>\n
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| 2<\/td>\n | undefined <\/td>\n<\/tr>\n | ||||||
| 7<\/td>\n | Annex ZA (normative)Normative references to international publicationswith their corresponding European publications <\/td>\n<\/tr>\n | ||||||
| 8<\/td>\n | Blank Page <\/td>\n<\/tr>\n | ||||||
| 9<\/td>\n | English CONTENTS <\/td>\n<\/tr>\n | ||||||
| 12<\/td>\n | FOREWORD <\/td>\n<\/tr>\n | ||||||
| 14<\/td>\n | INTRODUCTION <\/td>\n<\/tr>\n | ||||||
| 15<\/td>\n | 1 Scope 2 Normative references <\/td>\n<\/tr>\n | ||||||
| 16<\/td>\n | 3 Terms and definitions <\/td>\n<\/tr>\n | ||||||
| 18<\/td>\n | 4 Symbols, units and abbreviated terms <\/td>\n<\/tr>\n | ||||||
| 22<\/td>\n | 5 Overview of test method 6 Preparation for measurement of nacelle transfer function 6.1 General 6.2 Wind turbine <\/td>\n<\/tr>\n | ||||||
| 23<\/td>\n | 6.3 Test site 6.3.1 General <\/td>\n<\/tr>\n | ||||||
| 24<\/td>\n | 6.3.2 Terrain classification 6.4 Test plan 7 Test equipment 7.1 General <\/td>\n<\/tr>\n | ||||||
| 25<\/td>\n | 7.2 Data acquisition <\/td>\n<\/tr>\n | ||||||
| 26<\/td>\n | 8 Measurement procedure 8.1 General 8.2 Data system(s) synchronisation <\/td>\n<\/tr>\n | ||||||
| 27<\/td>\n | 8.3 Data collection 8.4 Data quality check 8.4.1 General 8.4.2 Measured signals are in range and available 8.4.3 Sensors are operating properly <\/td>\n<\/tr>\n | ||||||
| 28<\/td>\n | 8.4.4 Ensure data acquisition system(s) is(are) operating properly 8.4.5 Sector self-consistency check 8.5 Data rejection 8.6 Data correction <\/td>\n<\/tr>\n | ||||||
| 29<\/td>\n | 8.7 Database 9 Derived results 9.1 Overview of derived results <\/td>\n<\/tr>\n | ||||||
| 30<\/td>\n | 9.2 Determination of measured nacelle transfer function <\/td>\n<\/tr>\n | ||||||
| 31<\/td>\n | 9.3 Data quality check 9.3.1 General 9.3.2 Directional stability check <\/td>\n<\/tr>\n | ||||||
| 32<\/td>\n | 9.3.3 Self-consistency check for NTF, using the NPC 9.4 Uncertainty analysis 10 Reporting format <\/td>\n<\/tr>\n | ||||||
| 34<\/td>\n | Figures Figure 1 \u2013 Presentation of example data: measured transfer function <\/td>\n<\/tr>\n | ||||||
| 35<\/td>\n | Tables Table 1 \u2013 Example of presentation of a measured power curve based on data from the meteorological mast, for consistency check <\/td>\n<\/tr>\n | ||||||
| 36<\/td>\n | Annex A (informative)Nacelle instrument mounting A.1 General A.2 Preferred method of anemometer’s mounting A.3 Preferred position of anemometer <\/td>\n<\/tr>\n | ||||||
| 37<\/td>\n | Figure A.1 \u2013 Mounting of anemometer on top of nacelle <\/td>\n<\/tr>\n | ||||||
| 38<\/td>\n | Annex B (normative)Evaluation of uncertainty in measurement B.1 General B.2 The measurands B.3 Uncertainty components <\/td>\n<\/tr>\n | ||||||
| 39<\/td>\n | Table B.1 \u2013 Uncertainty components in nacelle transfer function evaluation <\/td>\n<\/tr>\n | ||||||
| 40<\/td>\n | B.4 Wind direction uncertainty Table B.2 \u2013 Uncertainty components in nacelle based absolute wind direction <\/td>\n<\/tr>\n | ||||||
| 41<\/td>\n | Annex C (normative)Theoretical basis for determining the uncertainty of measurement using the method of bins C.1 General <\/td>\n<\/tr>\n | ||||||
| 42<\/td>\n | C.2 Propagation of uncertainty through the stages of NTF\/NPC measurement <\/td>\n<\/tr>\n | ||||||
| 43<\/td>\n | Table C.1 \u2013 Example cancellation sources <\/td>\n<\/tr>\n | ||||||
| 45<\/td>\n | C.3 Category A uncertainties C.3.1 General C.3.2 Category A uncertainty in electric power <\/td>\n<\/tr>\n | ||||||
| 46<\/td>\n | C.4 Category B uncertainties C.4.1 General Table C.2 \u2013 List of category A and B uncertainties for NTF <\/td>\n<\/tr>\n | ||||||
| 47<\/td>\n | C.4.2 Category B uncertainties in climatic variations C.5 Expanded uncertainty Table C.3 \u2013 Expanded uncertainties <\/td>\n<\/tr>\n | ||||||
| 48<\/td>\n | Annex D (normative)NTF uncertainty estimates and calculation D.1 Methods and assumptions D.1.1 General D.1.2 Site calibration <\/td>\n<\/tr>\n | ||||||
| 49<\/td>\n | Table D.1 \u2013 Estimates for uncertainty components from site calibration <\/td>\n<\/tr>\n | ||||||
| 50<\/td>\n | D.1.3 Nacelle transfer function uncertainty component estimates <\/td>\n<\/tr>\n | ||||||
| 51<\/td>\n | Table D.2 \u2013 Estimates for uncertainty components from NTF measurement <\/td>\n<\/tr>\n | ||||||
| 52<\/td>\n | D.1.4 Nacelle power curve uncertainty component estimates D.1.5 Wind direction uncertainty <\/td>\n<\/tr>\n | ||||||
| 53<\/td>\n | Table D.3 \u2013 Estimates for uncertainty components for wind direction <\/td>\n<\/tr>\n | ||||||
| 54<\/td>\n | D.1.6 Contribution factors Table D.4 \u2013 Estimates for contribution factors for site calibration <\/td>\n<\/tr>\n | ||||||
| 55<\/td>\n | D.2 Uncertainty example calculations D.2.1 Example description Table D.5 \u2013 Estimates for contribution factors for NTF <\/td>\n<\/tr>\n | ||||||
| 56<\/td>\n | D.2.2 Example case \u2013 NTF uncertainty D.2.3 Example case \u2013 NPC uncertainty <\/td>\n<\/tr>\n | ||||||
| 58<\/td>\n | Annex E (normative)Allowable anemometry instrument types E.1 General E.2 Recalibration of sonic anemometers E.3 Uncertainty of sonic and propeller anemometers <\/td>\n<\/tr>\n | ||||||
| 59<\/td>\n | Annex F (informative)Organisation of test, safety and communication F.1 General F.2 Responsibility for test F.3 Safety during test F.4 Communication F.5 Prior to test F.6 During test <\/td>\n<\/tr>\n | ||||||
| 60<\/td>\n | F.7 After test <\/td>\n<\/tr>\n | ||||||
| 61<\/td>\n | Annex G (informative)NTF flowchart Figure G.1 \u2013 NTF flowchart <\/td>\n<\/tr>\n | ||||||
| 62<\/td>\n | Bibliography <\/td>\n<\/tr>\n<\/table>\n","protected":false},"excerpt":{"rendered":" Wind energy generation systems – Measurement based nacelle transfer function of electricity producing wind turbines<\/b><\/p>\n |