Research On The Analysis Method And Evaluation Technology Of Wind Turbine Reliability Based On The Operating Data

Grid-connected wind power generation is one of the most popular technologies for renewable energy generation. It also owns good prospects for development. In recent years, wind energy utilization industry in China has made considerable progress, and the wind power installed capacity has been in a leading position around the world. However, as an emerging energy industry with great increasing development, wind power generation still faces many urgent problems. Especially, there are prominent problems for the safe operation and reliability of wind turbines. Many servicing compositions of wind turbines are complex. The equipment failure and reliability problems occur frequently.This is due to the following two aspects. First, in order to meet the urgent requirement for the early industrial development, the development cycle, such as design and stereotype, is short for most existing units. It is very difficult to obtain the basic experimental data of equipments to finish reliability analyzing. Second, up to now, the study on the reliability of whole wind turbine is still lack. In recent 10 years, wind turbines have become large scales. Many operation data are accumulated, but we do little researches on statistic and analysis in depth, and make the valuable information resources idle and waste. In view of such phenomena, we need to analyze the collected operation data, study the unit reliability question and assess the technology performance and status for wind turbines, which is one of the key problems for the healthy development of wind power industry.To solve above problems, the author investigate and study many wind power enterprise in-depth. Based on the operation reliability of the complete machine with the actual operation data, this dissertation carries out the research related to reliability analysis and evaluation technology. The aim is to provide support and reference for selecting set, optimizing operation and making maintenance strategy. So this dissertation systematically analyzes the characteristics of the industry and the operation data of wind power in China, and studies analysis and assessment methods of wind turbines reliability based on the operation data. According to the characteristics of the lack of data during trial operating period, analysis methods of wind turbine reliability under the condition of the small sample are studied. Then the author proposes evaluation methods of units performance based on performance reliability with monitoring parameters of running process.The main achievements are listed as follows:(1) Study basic methods of wind turbine operating reliability analysis and assessment.For the wind turbine complete operating reliability, this dissertation studies the extraction method of indexes which reflect the units complete reliability and develops assessment models which apply to wind turbines with the operating data,.1) The operating system recorded data, event data and maintenance log are comprehensively analyzed, and then the data are transformed for the reliability analysis basic data. This dissertation systematically studies extraction methods of reliability index of wind turbine. The results show that the propose methods can effectively extract the reliability index when the sample size is sufficient.2) Based on operating reliability, a quantitative analysis model of unit maintenance strategy is constructed, and then two kinds of maintenance strategies are analyzed. The results show that the proposed model can be used to evaluate the quality of maintenance strategy.3) Considering the fuzzy characteristic in the process of wind turbines reliability evaluation, the average availability is difficult to accurately reflect the reliability level of units. The wind turbine fuzzy comprehensive evaluation model based on multiple parameters is constructed. It is verified through operating data of 20 units of a wind farm in north China. It turns out that the model can more accurately reflect the units’reliability level.(2) Study the wind turbine reliability analysis and evaluation methods using small sample data during trial period.The basic methods can accurately evaluate wind turbines reliability when the sample data are sufficient. However, the fault data are lack because the operation time is short during the trial operation period. It is difficult to evaluate the unit reliability in this period. To solve this problem, we study wind turbines reliability analysis and evaluation methods based on small sample set.1) Using the fault information of parts, combining the information entropy theory, and converting the component fault information into complete machine test information, we proposed wind turbines reliability entropy method based on components information. And the results show that the proposed method can estimate the complete machine operating reliability.2) Using multi-units downtime data of the same type during the trial period, wind turbines MDT analysis model is constructed here. The model is tested by the actual operation data during the trial operating period in a wind farm.3) The estimation model of MTBF in wind turbines is proposed. The model constructs the random censoring data of the wind turbine time between failures. The reliability is estimated by using Kaplan-Meier none parameter method. The distribution function is fitted by using the estimation results. Then according to the mathematical properties of the fitting function, the MTBF of unit is estimated. The MTBF of a wind farm with 20 units during the trial period is estimated. The results show that the model proposed in this dissertation can accurately estimate MTBF under small sample data.(3) Study and propose the analysis and assessment method of wind turbines performance based on performance reliability theoryIn view of the existing engineering and production problems in practice, this dissertation studies wind turbines performance analysis and evaluation methods based on the data recorded in SCADA and the performance reliability theory.1) It is difficult to evaluate the power curve in wind turbines acceptance test. In order to solve this problem, this dissertation re-analyzes the power curve approval requirement, and provides the probability interpretation. Then the power curve acceptance problem is turned into the problem of reliability assessment, and an evaluation model based on performance reliability theory is developed. The case study results show the efficient of the model.2) Wind turbines output power has fluctuation, randomness characteristics when units run in a particular wind speed. Using the characteristics, wind turbines performance analysis and evaluation methods are studied in this dissertation. Three models are established respectively for different type units, a single unit, and a unit running in different wind speed. Case studies show that these models can analyze wind turbines’performance successfully.3) Adopting the actual running temperature of a DDWT’s generator stator wingding as the research object, a real time reliability monitoring model is established. Using the regression technique, the model turns the measured temperature into the random data which are not affected by the environment temperature and the output power. Then we use the performance reliability theory and SPC technique to build the model. Taking No.1 unit of a wind farm in Shanxi province as example, the real-time reliability monitoring model of generator operation process is established.The results show all researches of this dissertation from different aspects can efficiently analyze the reliability level of wind turbines. The results of this dissertation can provide technical support and scientific basis for wind turbines operation optimization, maintenance strategy, and performance evaluation.