Advanced Wind Turbine Program Next Generation Turbine ... - NREL

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A blade certification testing program was conducted at the National Wind Technology Center (NWTC) in Golden, Colorado, under the supervision of personnel of the National Renewable Energy Laboratory. Fatigue testing of a GE34a blade began in August 2001, and was completed January 10, 2002. The same blade was used as had been subjected to the static testing described above. The objective of the fatigue test was originally to conduct a limited life fatigue test in order to give basic assurance that no major catastrophic fatigue failures are likely. The target number of test cycles was 300,000 for a ten percent life. This was based on observations that past fatigue testing has revealed problems early in the test duration. Later, this objective was expanded to include a full 20-year life of damage using a one-million-cycle load duration. The test operated for 1.9 million cycles. (a) Blade Setup (b) Two-Axis Hydraulic Actuator Figure 29. NWTC Fatigue Test Setup Loads were provided to NWTC by GE Wind to represent a 3-million-cycle design life. The testing began with the 3 million cycle loads. Beginning at approximately 928,000 cycles, however, the test loads were increased to accelerate the test to achieve 100% damage in 1 million cycles. Table 5 summarizes the operationally equivalent fatigue damage resulting from the fatigue test at various spanwise locations on the blade. These results were determined via finite element analysis of the blade. These results indicate that the critical test regions of the blade were tested to at 55
least 20 years of equivalent loading, the design life of the blade, without significant loss of global properties. In summary, NWTC concluded from the fatigue tests that the blade sustained the full load spectrum without significant loss of properties, including stiffness and ability to carry load. 3.1.5 POC Hub Analysis Table 5. Test Equivalent Damage Spanwise Test Life (Years) Notes Station z [m] Flap Edge 6.4 16.4 2.0 9.2 25.9 5.6 12.8 37.3 21.7 Critical Flap Station 16.9 20.2 37.6 Critical Edge Station 20.9 0.1 5.0 Figure 30 shows the POC hub on the floor of GE's manufacturing plant. During the NGT program, concern arose that much better fatigue properties for the GGG40.3 ductile cast iron used in the hub were required. A subcontract was issued to conduct an exhaustive materials characterization effort for this material. Analyses of the hub static stresses and fatigue concluded that, with a redesign of one small part, the hub does not appear to have any fatigue-driven problems. Therefore, it was concluded that the hub is acceptable in fatigue for greater than 20 years. 3.2 Installation and Testing of the Proof of Concepts Turbine The POC turbine was erected at the GE facility in Tehachapi, California. Installation was completed in April 2000. The turbine was installed on a free-standing 63-m tubular steel tower on a 5-m concrete pedestal foundation. The rotor installation is illustrated in Figure 31, and the completed POC turbine is shown in Figure 32. Certification testing of the POC turbine for noise, loads, power performance, and power quality has been completed under the supervision of personnel of the National Renewable Energy Laboratory. 56 Figure 30. POC Hub
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National Renewable Energy Laborator
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NOTICE This report was prepared as
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Abstract This document reports the
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In addition to innovations resultin
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3.2.3 Mechanical Loads Testing of t
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List of Symbols and Abbreviations A
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The SOW also stipulates that GE see
Page 15 and 16: 2.1 Electromechanical Systems Conce
Page 17 and 18: Table 1. Summary of the Key Drive T
Page 19 and 20: 2.1.1 Conventional-Speed Generators
Page 21 and 22: other than the wound rotor inductio
Page 23 and 24: offer compelling advantages to COE.
Page 25 and 26: cluded that the same would likely b
Page 27 and 28: cannot be designed for unity power
Page 29 and 30: Figure 5. Fatigue Damage Equivalent
Page 31 and 32: 2.3 Rotor and Structural Design Con
Page 33 and 34: 2.3.1.1 Upwind Rotor Blade and Towe
Page 35 and 36: Percent Change in Load Percent Chan
Page 37 and 38: the other three combinations of rot
Page 39 and 40: Percent Reduction in Component of F
Page 41 and 42: Design rules were used to estimate
Page 43 and 44: formed using the baseline rotor des
Page 45 and 46: duce an average flapwise deflection
Page 47 and 48: would be to reduce the COE by reduc
Page 49 and 50: 2.3.5 Boundary Layer Control GE com
Page 51 and 52: Perhaps the most important outcome
Page 53 and 54: Table 3. Proof of Concepts Turbine
Page 55 and 56: Figure 16. Schematic of the Proof o
Page 57 and 58: • Measure thermal characteristics
Page 59 and 60: Figure 21. POC Drive Train on the N
Page 61 and 62: • The lift and drag characteristi
Page 63 and 64: Figure 24. NGT POC Airfoil Family F
Page 65: One of the prototype blades was ini
Page 69 and 70: 3.2.1 Power Performance Testing of
Page 71 and 72: Maxi mum Ti p Speed (m/s) Sound Pow
Page 73 and 74: Table 6. Engineering & Manufacturin
Page 75 and 76: GE briefly considered the costs and
Page 77 and 78: Figure 38. EMD 37-m (GE37a) Blade 6
Page 79 and 80: Development of the concept required
Page 81 and 82: Bench tests verified PLC control mo
Page 83 and 84: 4.3.2 Mechanical Loads Testing of t
Page 85 and 86: 5 Commercialization of GE NGT Techn
Page 87: F1146-E(12/2004) REPORT DOCUMENTATI
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