% % This file was created by the TYPO3 extension % bib % --- Timezone: CEST % Creation date: 2024-04-24 % Creation time: 06-15-52 % --- Number of references % 26 % @Conference { , title = {Review of Efficiency Measurement Standards for Wind Turbines on Nacelle Test Benches: Based on Small-Scale Test Benches for Electrical Machines}, year = {2023}, month = {9}, abstract = {There is a huge global demand for clean renewable energy sources to compensate for energy-related carbon dioxide (CO 2 ) emissions. The widespread development of multi-megawatt wind turbines with increased energy efficiency is playing an important role in meeting this demand for clean energy. Traceable efficiency measurements for wind turbines on test benches or in the field are thus very crucial. They are also of great interest for evaluating the usability of wind energy. However, no standardized methods are currently available for the traceable efficiency determination of wind turbines on test benches during the design phase. In this paper, a review of standards of efficiency measurements for rotating electrical machines on test benches is summarized. Furthermore, an innovative measurement concept for small-scale test benches with results that are similar to those of nacelle test benches for wind turbines is presented.}, keywords = {Efficiency losses nacelle test bench rotating electrical machines small-scale test bench wind turbine}, url = {t3://file?uid=9263 _blank}, publisher = {Physikalisch-Technische Bundesanstalt}, event_place = {Gyeongju, Korea}, event_name = {24th International Conference on Electrical Machines and Systems (ICEMS)}, event_date = {31 Oct.-3 Nov. 2021}, language = {En}, DOI = {10.7795/EMPIR.19ENG08.CA.20230831B}, author = {Yogal, Nijan and Lehrmann, Christian and Zhang, Hongkun and Song, Zihang and Weidinger, Paula and Kumme, Rolf} } @Conference { , title = {Accurate Rotational Speed Measurement for Determining the Mechanical Power and Efficiency of Electrical Machines}, year = {2023}, month = {9}, abstract = {Accurately measuring the mechanical power of electrical machines is essential for determining their efficiency. Conventionally, the machines' rotational speed is measured over a short time interval with a high measurement uncertainty. In this paper, we propose a rotational speed determination based on the angle covered within a longer time interval. This method is shown to achieve a higher accuracy for the determination of mechanical power and total efficiency with negligible systematic effect.}, keywords = {Power measurement Torque Systematics Velocity control Measurement uncertainty Mechanical variables measurement Time measurement}, url = {t3://file?uid=9262 _blank}, publisher = {Physikalisch-Technische Bundesanstalt}, event_place = {Gyeongju, Korea}, event_name = {24th International Conference on Electrical Machines and Systems (ICEMS)}, event_date = {31 Oct.-3 Nov. 2021}, language = {EN}, DOI = {10.7795/EMPIR.19ENG08.CA.20230831A}, author = {Song, Zihang and Weidinger, Paula and Kumme, Rolf} } @Article { , title = {Estimation of Uncertainty for the Torque Transducer in MNm Range—Classical Approach and Fuzzy Sets}, journal = {Energies, 16.16(6064): 1-20}, year = {2023}, month = {8}, abstract = {The work provides an analysis of the metrological properties of a 5 MN m torque transducer. The relative electrical signal (given in electrical units, mV/V) as a function of torque measured in both the clockwise and anticlockwise directions was monitored. To fit the data, the weighted method of least squares with both a straight-line and a cubic spline curve was used. The work presents the results of estimating both the relative and absolute uncertainty using two methods: uncertainty propagation and Monte Carlo simulation. The results of the analysis indicated that the straight-line fitting method produced smaller values for the expanded uncertainty than the cubic spline fitting method. Moreover, the study confirmed the assumptions that theMCMfor propagating uncorrelated distributions was more accurate than the LPU method, regardless of the type of curve fitting used. In the torque range above 200 kN m, the expanded relative uncertainty of the measured signals was at the level of (0.03 ÷ 0.04) \% for the straight-line fitting method and about 0.05\% for the cubic spline fitting method. In the calibrated range below 1 MN m, with linear fitting in both directions, the absolute expanded uncertainty of the normalised signal was below 0.0001 mV/V. In addition, matching to the measured coordinates was performed with cubic splines, i.e., polynomials of the third degree, which, due to their characteristics, can adjust to various types of nonlinearities. In interpolating problems, cubic spline interpolation is often preferred to other polynomials with a higher degree . But this interpolation, in general, cannot be used for analytic continuation—the extrapolation of characteristics using cubic spline in a range not measured by the instrument, e.g., the torque transducer. Additionally the expanded uncertainties estimated from the Monte Carlo method for all cases were much higher for cubic spline than for linear interpolation. Finally, we explored how to evaluate uncertainty using fuzzy sets, and an approximation of the expanded uncertainty’s value was computed. Overall, the study provides a detailed analysis of the metrological properties of the torque transducer and presents a comparison of different methods for estimating the uncertainty above a calibratable range. The findings can be useful for researchers and engineers working with torque transducers and those in the wind turbine sector expanding the development of more precise measurement techniques.}, keywords = {torque transducer reference torque standard machine measurement uncertainty calibration wind energy weighted least squares method Monte Carlo method law of propagation of uncertainty fuzzy sets}, url = {t3://file?uid=9260}, language = {En}, DOI = {https://doi.org/10.3390/en16166064}, author = {Fidelus, Janusz and Puchalski, Jacek and Trych-Wildner, Anna and Urbanski, Michał K. and Weidinger, Paula} } @Article { , title = {The Creep Behaviour of a 2 kN*m Torque Transducer Tested at GUM and PTB}, journal = {Measurement 2023, Proceedings of the 14th International Conference}, year = {2023}, month = {5}, abstract = {This article outlines the metrological characterisation of a 2kN*m torque transducer conducted at the Central Office of Measures (GUM) and Physikalisch-Technische Bundesanstalt (PTB). The linear regression equations for this torque transducer were determined using the weighted least sqare method. In all calculations, the Monte Carlo method was used to estimate the expanded uncertainties, which were found to be lower than those calculated using the law of propagation of uncertainty. Additionally, a creep study was conducted at eight measurement points ranging from 200 N*m to 2000 N*m}, url = {t3://file?uid=8913}, web_url = {t3://file?uid=8912}, event_place = {Smolenice, Slovakia}, event_name = {Measurement 2023}, ISBN = {978-80-972629-6-9}, author = {Fidelus, Janusz and Puchalski, Jacek and Trych-Wildner, Anna and Weidinger, Paula} } @Article { , title = {Importance of Traceability for Determining the Efficiency of wind turbine drive trains on test benches}, journal = {SMSI 2023 Conference – Sensor and Measurement Science International}, year = {2023}, month = {5}, abstract = {In this paper, the efficiency of a 2.75 MW nacelle is compared using calibrated and uncalibrated measurement devices. The results show that especially calibration of mechanical input is important, as the torque measurement is off by about 5 \% and results in significantly lower system efficiencies.}, keywords = {Calibration, efficiency determination, nacelle system test bench, mechanical input power, electrical output power}, url = {t3://file?uid=8910}, event_name = {SMSI 2023 Conference – Sensor and Measurement Science International}, language = {EN}, DOI = {10.5162/SMSI2023/P52}, author = {Song, Zihang and Weidinger, Paula and Zweiffel, Maximilian and Dubowik, Alexander and Soares Oliveira, Rafael and Yogal, Nijan and Mester, Christian} } @Article { , title = {Zero Signal Determination for Torque Measurement Under Rotation in Test Benches}, journal = {SMSI 2023 Conference – Sensor and Measurement Science International}, year = {2023}, month = {5}, abstract = {This paper discusses the problem of determining the zero point when measuring torque under rotation. Two approaches are presented and analysed: static zero signal determination, which should be used for efficiency calculation, and rotational zero signal determination, which should be used for test bench torque calibration under rotation.}, keywords = {zero signal determination, offset determination, torque measurement, torque under rotation, torque in test benches}, url = {t3://file?uid=8911}, event_date = {SMSI 2023 Conference}, language = {EN}, DOI = {10.5162/SMSI2023/D4.2}, author = {Weidinger, Paula and Song, Zihang and Zhang, Hongkun and Zweiffel, Maximilian and Soares Oliveira, Rafael} } @Article { , title = {Direct measurement of input loads for the wind turbine drivetrain under test on a nacelle test bench}, journal = {Forschung im Ingenieurwesen}, year = {2023}, month = {3}, day = {20}, abstract = {Modern wind turbines have some of the highest levels of torque and non-torque loads of all industrial sectors. These high loads present a great challenge for the design of wind turbines. On a nacelle test bench, the wind turbine drivetrain can be tested and validated against the design. It is therefore important to measure the correct level of each load and all its dynamic behaviors during the test. The best way to achieve this is to measure the loads directly in front of the drivetrain. This paper presents a method of direct load measurement on the shaft adapter which connects the drivetrain to the test bench. The technical solution and some important details about the instrumentation on the adapter are also presented. Methods of signal nulling as well as signal conversion from raw signals to the loads are compared as well. The measurements obtained are then compared with the applied loads from the test bench which show good agreement. As a special case, the torque measurement is validated and calibrated up to 5MNm by means of a state-of-the-art torque transducer.}, url = {t3://file?uid=8482}, publisher = {Springer}, howpublished = {online}, language = {EN}, DOI = {https://doi.org/10.1007/s10010-023-00628-z}, author = {Zhang, Hongkun and Pieper, S{\"o}ren and Heller, Marcel} } @Article { , title = {Influence of drivetrain efficiency determination on the torque control of wind turbines}, journal = {Forschung im Ingenieurwesen}, year = {2023}, month = {3}, day = {20}, abstract = {Decreasing the levelized cost of energy is a major design objective for wind turbines. Accordingly, the control is generally optimized to achieve a high energy production and a high-power coefficient. In partial load range, speed and torque are controlled via the generator torque but the rotor torque determines the power coefficient of the turbine. High uncertainties for the uncalibrated low-speed shaft torque measurement and varying drivetrain efficiencies which depend on the speed, load and temperature lead to a torque control error that reduces the power coefficient of the wind turbine. In this paper the rotor torque control error and the impact on the power coefficient of wind turbines is quantified. For this purpose, the variation of drivetrain efficiency is analyzed. An efficiency model for the wind turbine drivetrain is build and validated on the test bench. Then, the influence of the drivetrain speed, torque loads, non-torque loads, and temperature on the efficiency is quantified. Finally, the influence of the rotor torque control error on the power coefficient was simulated with an aerodynamic model. The results show that of all examined influences only torque and temperature significantly impacting the efficiency leading to rotor torque control errors that reduce the power coefficient and consequently increase the levelized cost of energy. Improved efficiency measurement on WT test benches or drivetrain efficiency modelling can reduce the rotor torque control error and therefore decrease the LCOE.}, url = {t3://file?uid=8481}, publisher = {Springer}, howpublished = {Online}, language = {EN}, DOI = {https://doi.org/10.1007/s10010-023-00630-5}, author = {Zweiffel, Maximilian and Jacobs, G. and Song, Zihang and Weidinger, Paula and Decker, T. and R{\"o}der, J. and Bosse, D.} } @Article { , title = {Traceable efficiency determination of a 2.75 MW nacelle on a test bench}, journal = {Forschung im Ingenieurwesen}, year = {2023}, month = {3}, day = {20}, abstract = {In this paper, the efficiency of a 2.75MWnacelle drivetrain on a test bench was determined traceably at various load points. For this purpose, so-called transfer standards for mechanical and electrical power measurement were additionally installed and integrated into the nacelle drivetrain. As torque measurement contributes greatly to the overall uncertainty, the static torque calibration was expanded to include additional influences present under rotation. An overall system efficiency of 89\% was measured in the high torque and high speed range. The relative expanded measurement uncertainty for efficiency determination was between 0.30\% and 0.72\% over the entire operating range. Both the efficiency and the relative expanded measurement uncertainty were calculated for each operating point.}, url = {t3://file?uid=8480}, publisher = {Springer}, howpublished = {Online}, language = {EN}, DOI = {https://doi.org/10.1007/s10010-023-00650-1}, author = {Song, Zihang and Weidinger, Paula and Zweiffel, Maximilian and Dubowik, Alexander and Mester, Christian and Yogal, Nijan and Soares Oliveira, Rafael} } @Conference { , title = {Transducer response under non-standardised torque load profiles}, year = {2022}, month = {10}, abstract = {In nacelle system test benches, different wind profiles are simulated by applying different torque loads and rotational speeds amongst other things. Unlike load sequences during calibration measurements, these profiles are neither constant nor increasing and decreasing through controlled steps. This article proposes a sequence of partial range and shuffled torque load tests that combine torque rates and filter settings to evaluate parameters affecting the measurement results, such as output sensitivity, linearity, and hysteresis.}, keywords = {torque calibration; DIN 51309; DKD-R 3-9; transient torque load; randomly shuffled loading}, url = {t3://file?uid=8479}, event_place = {Cavtat-Dubrovnik, Croatia}, event_name = {IMEKO 24th TC3, 14th TC5, 6th TC16 and 5th TC22 International Conference}, event_date = {11 – 13 October 2022}, DOI = {https://doi.org/10.21014/tc3-2022.083}, author = {Soares Oliveira, Rafael and Weidinger, Paula and Song, Zihang and Vavrečka, L. and Fidelus, Janusz and Kananen, Timo and Kilponen, Sauli} } @Conference { , title = {Applicability of torque calibration on test benches for electrical machines}, year = {2022}, month = {10}, abstract = {The traceability of torque measurements on test benches for electrical machines is primarily established by the static calibration of a torque transducer. However, the loading conditions and signal processing methods are generally different for the static calibration and the measurement on a test bench. Therefore, the applicability of the calibration should be clarified before applying the calibration results for further analysis. In this paper, the torque measurement chain using a power analyser on a test bench for electrical machines is compared to the measurement chain used in the standard calibration procedure DIN 51309.}, keywords = {DIN 51309; torque measurement; torque calibration; power analyser; motor test bench}, url = {t3://file?uid=8477}, event_place = {Cavtat-Dubrovnik, Croatia}, event_name = {IMEKO 24th TC3, 14th TC5, 6th TC16 and 5th TC22 International Conference}, event_date = {11 – 13 October 2022}, language = {EN}, DOI = {https://doi.org/10.21014/tc3-2022.068}, author = {Song, Zihang and Weidinger, Paula and Yogal, Nijan and Soares Oliveira, Rafael and Lehrmann, Christian and Kumme, Rolf} } @Conference { , title = {Efficiency measurement with a focus on the influence of rotation and temperature on torque measurements performed on small-scale test benches}, year = {2022}, month = {10}, abstract = {Torque measurements that account for the influences of temperature and rotation are vital in determining the efficiency of rotating electrical machines on test benches. During experimental efficiency measurements, the influences of temperature and rotational speed generate errors in the torque measurements that could also affect the overall traceable efficiency measurement on test benches. In this paper, experimental efficiency mapping results with a focus on the influence of rotation and temperature on torque measurements are presented.}, keywords = {efficiency measurement; rotating electrical machines; torque calibration; torque measurement under rotation}, url = {t3://file?uid=8478}, event_place = {Cavtat-Dubrovnik, Croatia}, event_name = {IMEKO 24th TC3, 14th TC5, 6th TC16 and 5th TC22 International Conference}, event_date = {11 – 13 October 2022}, language = {EN}, DOI = {https://doi.org/10.21014/tc3-2022.083}, author = {Yogal, Nijan and Lehrmann, Christian and Song, Zihang and Weidinger, Paula and Kumme, Rolf and Soares Oliveira, Rafael} } @Article { , title = {A phase reference for ADC delay characterisation}, year = {2022}, abstract = {In an increasing number of applications, analogue signals are acquired and timestamped. The quantities of interest, such as active power or phasors in a three-phase system, are calculated in fully digital pieces of equipment based on data from different digital sources such as instrument transformers with digital output. Therefore, the requirements for the timestamping become more and more challenging where traditionally, analogue voltage and current were digitised on the same circuit board and timestamping with a resolution of a second was largely sufficient. This paper presents a phase reference that does not depend on assumptions about the alignment of sine and square wave signals.}, url = {t3://file?uid=8483}, howpublished = {Online}, language = {EN}, author = {Mester, Christian} } @Conference { , title = {Validierung eines Verfahrens zur Wirkungsgradbestimmung von Windenergieanlagen auf Pr{\"u}fst{\"a}nden}, journal = {19. Technischer Tag der VEM-Gruppe}, year = {2022}, abstract = {The methods for determining the efficiency of rotating electrical machines are specified in the EN 60034 series of standards: mains-powered machines are treated in the EN 60034-2-1 standard and frequency converter-fed machines in the EN 60034-2-3 standard. According to EN 60034-2-1, the use of the summation of losses method with residual loss determination is recommended for asynchronous machines to ensure the lowest possible measurement uncertainty. One advantage here, for example, is that constant offset errors in torque measurement do not directly affect the efficiency. In principle, these methods, which are established in the industrial drives sector, can also be used to determine the efficiency of generators in wind energy systems. However, the procedures required by the standards are often not feasible in nacelle test benches. Due to the lack of applicable standards, the Fraunhofer Institute for Wind Energy Systems (IWES) developed a modified method for determining the efficiency of generators in wind energy systems. This procedure is based on the back-to-back procedure described in EN 60034-2-1:2015 section 6.2.2. To validate the alternative back-to-back method, the results obtained were compared with the results obtained using the summation of losses method described in the EN 60034-2-1 standard. The comparative measurements were carried out on drives with different rated powers and frame sizes as part of the EMPIR project 19ENG08 – WindEFCY at PTB. In the context of the presentation, the validation process and its results are presented in detail.}, keywords = {Wind turbine Test bench Nacelle Measurement uncertainty}, url = {t3://file?uid=7724 _blank}, event_place = {Wernigerode}, event_name = {19. Technischer Tag der VEM-Gruppe}, event_date = {13.-14.09.2022}, language = {DE}, author = {Lehrmann, Christian and Weidinger, Paula and Yogal, Nijan and Song, Zihang} } @Conference { , title = {Metrological characterisation of rotational speed measurement using an inclinometer in a nacelle test bench}, journal = {Sensoren und Messsysteme 2022}, year = {2022}, pages = {165-168}, abstract = {The measurement of mechanical power in nacelle test benches is an essential part of determining the efficiency of wind turbines. For this purpose, the selected inclinometer is integrated into the torque transfer standard to build a transfer standard for mechanical power measurement. The metrological characteristics of rotational speed measurement using the inclinometer are investigated by considering the static calibration, the uncertainty contributions due to mounting misalignments, eccentricity, dynamic effects, and the process of data evaluation. Finally, the traceability chain of the rotational speed measurement is established.}, keywords = {Rotational speed Inclinometer Nacelle test bench}, url = {t3://file?uid=7729 _blank}, publisher = {VDE VERLAG GMBH ∙ Berlin ∙ Offenbach}, event_place = {N{\"u}rnberg}, event_name = {Sensoren und Messsysteme 2022}, event_date = {10.-11.05.2022}, language = {EN}, ISBN = {978-3-8007-5835-7}, author = {Song, Zihang and Weidinger, Paula and Zhang, Hongkun and Heller, Marcel and Soares Oliveira, Rafael and Kumme, Rolf} } @Conference { , title = {Proteccion y eficienca de aerogeneradores de energ{\'i}a dotados con compensadores de carga el{\'e}ctrica}, journal = {ENERG{\'E}TICAXXI}, year = {2022}, pages = {56-58}, abstract = {Los compensadores de carga el{\'e}ctrica son dispositivos pasivos, producidos por Dinnteco bajo la denominaci{\'o}n de DDCE1, que permiten la captaci{\'o}n y deriva a tierra de corrientes el{\'e}ctricas en el tiempo. Su funcionamiento se basa en equilibrar el campo el{\'e}ctrico variable en el entorno de la estructura que protegen, evitando que se generen trazadores el{\'e}ctricos ascendentes y absorbiendo tambi{\'e}n la energ{\'i}a electromagn{\'e}tica de radiofrecuencia. Es, por tanto, un sistema de protecci{\'o}n frente a descargas atmosf{\'e}ricas que evita el impacto en la infraestructura protegida, desvanece las acciones de radiofrecuencia de agentes exteriores y las derivadas de pulsos de corriente asociados a los rayos nube-nube y nube-tierra}, keywords = {Atmospheric discharges Lightning Protecion System}, url = {t3://file?uid=7725 _blank}, event_name = {ENERG{\'E}TICAXXI}, event_date = {03.2022}, language = {ES}, author = {Maldonado, Javier and Ana Saenz Nuno, Maria and Weidinger, Paula and Bernabeu, Eusebio} } @Conference { , title = {Evaluation of the uncertainty of a traceable efficiency determination method for wind turbine electrical machines in a small-scale test bench}, journal = {PEMD 2022 - The 11th International Conference on Power Electronics, Machines and Drives}, year = {2022}, abstract = {This paper examines the feasibility and practicability of international standards for determining the efficiency of wind turbine electrical machines on a test bench. Test methods combined with static calibration certificates from specialized instruments and sensors were used to evaluate the efficiency and determine the measurement uncertainty (MU) values in ambient conditions on a small-scale test bench (SSTB). These will next be studied on the nacelle test bench (NTB). The main test used to determine the performance of wind turbines is the direct efficiency method. For comparison, two other tests were done applying the indirect and modified back-to-back (MBTB) efficiency methods based on small-scale test bench measurements for wind turbines. The results were compared with a focus on MU values and are presented in this paper.}, keywords = {Efficiency Nacelle test bench Rotating electrical machines Small-scale test bench Standardization}, url = {t3://file?uid=7726 _blank}, event_place = {Newcastle, UK}, event_name = {PEMD 2022 - The 11th International Conference on Power Electronics, Machines and Drives}, event_date = {21.-23.06.2022}, language = {EN}, author = {Yogal, Nijan and Lehrmann, Christian and Zhang, Hongkun} } @Conference { , title = {Metrological evaluation of torque measurement up to 5 MN m under rotation in a 10 MW nacelle test bench}, journal = {Sensoren und Messsysteme 2022}, year = {2022}, pages = {59-62}, abstract = {The torque input to nacelles is of great importance for the efficiency determination of these nacelles. For a reliable and traceable torque measurement in nacelle test benches, a torque transfer standard is installed in the drive train directly at the rotor hub of the nacelle and certain combinations of torque and rotational speed, so-called characterisation maps, are applied and measured. In doing so, the torque measurement in the 10 MW nacelle test bench DyNaLab at Fraunhofer IWES is characterised metrologically up to 5 MN m in form of a relative indication deviation including the corresponding expanded measurement uncertainty.}, keywords = {Wind turbine Efficiency Test bench Measurement uncertainty}, url = {t3://file?uid=7727 _blank}, publisher = {VDE VERLAG GMBH ∙ Berlin ∙ Offenbach}, event_place = {N{\"u}rnberg}, event_name = {Sensoren und Messsysteme 2022}, event_date = {10.-11.05.2022}, language = {EN}, ISBN = {978-3-8007-5835-7}, author = {Weidinger, Paula and Song, Zihang and Heller, Marcel and Zhang, Hongkun and Eustorgi, Karin} } @Article { , title = {Need for a traceable efficiency determination method of nacelles performed on test benches}, journal = {Measurement: Sensors}, year = {2021}, month = {9}, day = {23}, volume = {18}, number = {100159}, pages = {1-4}, abstract = {For an energy transition towards renewable energy sources, the importance of traceable efficiency determination increases. There are standards for a traceable efficiency determination of rotating electrical machines as well as standards for a power curve determination of wind turbines in the field. To speed up and ameliorate the design process of a wind turbine, however, a standardised efficiency determination method for nacelle drive trains on test benches is required. In this paper, the need and recommendations for such an efficiency determination method are given.}, keywords = {Nacelle test bench Wind turbine power curves Direct efficiency determination Mechanical power measurement Electrical power measurement}, url = {t3://file?uid=6261}, publisher = {ELSEVIER}, howpublished = {open access journal}, language = {En}, DOI = {https://doi.org/10.1016/j.measen.2021.100159}, author = {Weidinger, Paula and Dubowik, Alexander and Lehrmann, Christian and Yogal, Nijan and Kumme, Rolf and Zweiffel, Maximilian and Eich, Norbert and Mester, Christian and Zhang, Hongkun} } @Article { , title = {10 MW mechanical power transfer standard for nacelle test benches using a torque transducer and an inclinometer}, journal = {Measurement: Sensors}, year = {2021}, month = {9}, day = {22}, volume = {18}, number = {100249}, pages = {1-5}, abstract = {Accurately measuring the mechanical power of wind turbines is essential for determining their efficiencies. As there is currently no standardized method available for a traceable mechanical power measurement of wind turbines, we propose a 10 MW mechanical power transfer standard based on a 5 MN⋅m torque transducer and an inclinometer for rotational speed measurements up to 20 min???? 1. In particular, the deviation of using an inclinometer is investigated both in simulation and experiments, and a compensation method is proposed. By tracing both the torque and the rotational speed measurements to national standards, it can offer a mechanical power measurement with 0.5 \% measurement uncertainty.}, keywords = {Nacelle test bench Wind turbine Inclinometer Rotational speed measurement Mechanical power measurement}, url = {t3://file?uid=6262}, publisher = {ELSEVIER}, howpublished = {open access journal}, DOI = {10.1016/j.measen.2021.100249}, author = {Song, Zihang and Weidinger, Paula and Eich, Norbert and Zhang, Hongkun} } @Conference { , title = {Challenges and potential solutions for determining the efficiency of wind turbines}, year = {2021}, month = {9}, day = {14}, abstract = {This presentation will elaborate on the EMPIR project and its goals and present the initial results of the investigations conducted at PTB's motor test field. One focus here will be on the testing of various efficiency determination methods to see which are most suitable for use on wind turbine test benches. We will further look at the current status of the calibration of the mechanical performance transfer standard and examine the solutions that have been developed for synchronizing the acquisition of measured data on a real wind turbine test bench.}, note = {Presentation in german language}, keywords = {Wind turbine Efficiency Nacelle test bench}, url = {t3://file?uid=6829}, web_url = {t3://file?uid=6827}, web_url2 = {t3://file?uid=6828}, event_place = {Wernigerode}, event_name = {18. Technischer Tag der VEM-Gruppe}, event_date = {14.-15.09.2021}, language = {DE}, author = {Lehrmann, Christian and Weidinger, Paula and Song, Zihang and Yogal, Nijan} } @Article { , title = {Sampling Primary Power Standard from DC up to 9 kHz Using Commercial Off-The-Shelf Components}, journal = {Energies}, year = {2021}, volume = {14}, number = {2203}, pages = {1-15}, abstract = {In the framework of the EMPIR projects MyRailS and WindEFCY, METAS developed a primary standard for electrical power using commercial off-the-shelf components. The only custom part is the software that controls the sampling system and determines the amplitude and phase of the different frequency components of voltage and current. The system operates from DC up to 9 kHz, even with distorted signals. The basic system is limited to 700V and 21A. Its power uncertainty is 15\(\mu\)W/VA at power frequencies and increases to 1.8mW/VA at 9 kHz. With the extension up to 1000V and 360A, the system reaches power uncertainties of 20\(\mu\)W/VA at power frequencies, increasing to 510\(\mu\)W/VA at 9 kHz. For higher voltages or higher currents, the same principle is used. However, the uncertainties are dominated by the stability of the sources. The voltage and current channels can also be used independently to calibrate and test power quality instruments. Thanks to a time-stamping system, the system can also be used to calibrate phasor measurement units, which are synchronised to UTC.}, keywords = {electrical power; EMPIR; MyRailS; WindEFCY; PMU; power quality; power standard; sampling; traceability; uncertainty}, url = {t3://file?uid=5812}, language = {English}, DOI = {https://doi.org/10.3390/en14082203}, author = {Mester, Christian} } @Conference { , title = {Nacelle efficiency performed on test benches - the metrological traceability for the input mechanical power}, journal = {Brazil Windpower Congress}, year = {2021}, abstract = {The existing guidelines about efficiency measurement of wind turbines rely on power curve measurements in the wind park, which is a very restrictive process due to the field conditions that cannot be controlled. More recently, the use of Nacelle Test Benches (NTB) to evaluate the efficiency of wind turbines is growing. These facilities provide a controlled environment for efficiency tests, as the input mechanical power is generated through a drive system combining loads of torque (prime mover) and force (load application system). These drive loads are able to simulate the same conditions that a wind turbine would feel under a wind flow in the “real field”. In this perspective, standardized tests and validation processes for nacelles on NTBs are needed to assure quality and reach comparability stages. The proceeding for the determination of the efficiency of nacelles and their components on NTBs however, has not been standardized nor tracked by metrological national standards until now. This article introduces the research approaches in metrology carried out in the context of the European Metrology Programme for Innovation and Research (EMPIR) by the respective projects “14IND14 - Torque measurement in the MN·m range (MNm Torque)” and “19ENG08 - Traceable mechanical and electrical power measurement for efficiency determination of wind turbines (WindEFCY)”. The challenges and achievements of metrological traceability for the NTB input Mechanical Power are explored in the article in a way to present the Windpower community which methodologies, objectives and governance structure and background are addressed by the mentioned projects.}, keywords = {Nacelle Test Bench Metrological Traceability Mechanical Power Measurement Torque Measurement Rotational Speed Measurement}, url = {t3://file?uid=7728 _blank}, event_place = {S{\~a}o Paulo, Brazil}, event_name = {Brazil Windpower Congress}, event_date = {3.-5.11.2021}, language = {EN}, author = {Soares Oliveira, Rafael and Weidinger, Paula and Song, Zihang} } @Conference { SongWEZYK2021, title = {Video presentation on ''10 MW mechanical power transfer standard for nacelle test benches using a torque transducer and an incliometer'' given at IMEKO2021 by Zihang Song.}, year = {2021}, url = {t3://file?uid=6833 _blank}, author = {Song, Zihang and Weidinger, Paula and Eich, Norbert and Zhang, Hongkun and Yogal, Nijan and Kumme, Rolf} } @Conference { , title = {Video presentation on ''Torque measurement under rotation in test benches'' given at the 2nd International Seminar on Dynamic Measurement by Zihang Song and Paula Weidinger.}, year = {2021}, url = {t3://file?uid=6825}, author = {Weidinger, Paula and Song, Zihang} } @Conference { , title = {Video presentation on ''Need for a traceable efficiency determination method of nacelles performed in test benches'' given at IMEKO2021 by Paula Weidinger.}, year = {2021}, url = {t3://file?uid=6826}, author = {Weidinger, Paula} }