This paper analyzes the errors in Chinese college students＇ compositions. The study finds that among the three types of errors： interference errors, intralingual errors and developmental errors, developmental errors...This paper analyzes the errors in Chinese college students＇ compositions. The study finds that among the three types of errors： interference errors, intralingual errors and developmental errors, developmental errors are the most important errors in the Chinese college students＇ writing. The results will help Chinese EFL teachers （especially college teachers） and students better judge the errors in the English writings of the Chinese students. It will also help the students avoid different kinds of errors in English writing.展开更多
Numerical weather prediction(NWP)models have always presented large forecasting errors of surface wind speeds over regions with complex terrain.In this study,surface wind forecasts from an operational NWP model,the SM...Numerical weather prediction(NWP)models have always presented large forecasting errors of surface wind speeds over regions with complex terrain.In this study,surface wind forecasts from an operational NWP model,the SMS-WARR(Shanghai Meteorological Service-WRF ADAS Rapid Refresh System),are analyzed to quantitatively reveal the relationships between the forecasted surface wind speed errors and terrain features,with the intent of providing clues to better apply the NWP model to complex terrain regions.The terrain features are described by three parameters:the standard deviation of the model grid-scale orography,terrain height error of the model,and slope angle.The results show that the forecast bias has a unimodal distribution with a change in the standard deviation of orography.The minimum ME(the mean value of bias)is 1.2 m s^(-1) when the standard deviation is between 60 and 70 m.A positive correlation exists between bias and terrain height error,with the ME increasing by 10%−30%for every 200 m increase in terrain height error.The ME decreases by 65.6%when slope angle increases from(0.5°−1.5°)to larger than 3.5°for uphill winds but increases by 35.4%when the absolute value of slope angle increases from(0.5°−1.5°)to(2.5°−3.5°)for downhill winds.Several sensitivity experiments are carried out with a model output statistical(MOS)calibration model for surface wind speeds and ME(RMSE)has been reduced by 90%(30%)by introducing terrain parameters,demonstrating the value of this study.展开更多
Complementary-label learning(CLL)aims at finding a classifier via samples with complementary labels.Such data is considered to contain less information than ordinary-label samples.The transition matrix between the tru...Complementary-label learning(CLL)aims at finding a classifier via samples with complementary labels.Such data is considered to contain less information than ordinary-label samples.The transition matrix between the true label and the complementary label,and some loss functions have been developed to handle this problem.In this paper,we show that CLL can be transformed into ordinary classification under some mild conditions,which indicates that the complementary labels can supply enough information in most cases.As an example,an extensive misclassification error analysis was performed for the Kernel Ridge Regression(KRR)method applied to multiple complementary-label learning(MCLL),which demonstrates its superior performance compared to existing approaches.展开更多
Chinese non-English majors are a large group of English learners.In the process of English pronunciation acquisition,issues such as incomplete phonological knowledge,transfer of mother tongue,and overgeneralization,le...Chinese non-English majors are a large group of English learners.In the process of English pronunciation acquisition,issues such as incomplete phonological knowledge,transfer of mother tongue,and overgeneralization,lead to confusion of phonemes and stress,misunderstanding of syllable structure,and errors of assimilation,drop,and epenthesis.The accuracy of English pronunciation can only be improved by knowing both English and Chinese phonological systems,strengthening the teaching of English phonological knowledge,and adopting various phonological training activities.展开更多
Before cognitive approach came into being in the 1960s, errors in L2 learning were always regarded as signs of failure which needed immediate attention from the teacher. By analyzing a student＇s writing, this paper t...Before cognitive approach came into being in the 1960s, errors in L2 learning were always regarded as signs of failure which needed immediate attention from the teacher. By analyzing a student＇s writing, this paper tries to elaborate on the roles that errors can play in L2 learning process.展开更多
English is considered as Arab students＇ second language which is not used frequently in their daily conversations. Since writing in English is a challenging experience for Omani students, errors in grammar and senten...English is considered as Arab students＇ second language which is not used frequently in their daily conversations. Since writing in English is a challenging experience for Omani students, errors in grammar and sentence structures were identified in bridging language courses （foundation level 2） in the field of ESL （English as a Second Language}. Learners＇ errors were considered positively as the best sources to identify students＇ limitations in English writing. The present study investigates the structure errors of Omani students＇ writings in English in foundation level 2 at Arab Open University. The focal aim is to study the errors that Ornani students commit when they are using adjectives ＋ nouns, indefinite articles, and subordinate conjunction ＂because＂. Results show that Omani students committed the following common errors： misplacement of adjectives, omission of the indefinite articles, and wrong structure of the subordinate conjunction （because）. The prime aim of this study is to examine the students＇ aforementioned structural errors which are the result of the interference of their mother-tongue. In order to achieve these aims, students were asked to write two different topics. Finally, this research suggests further recommendations for further studies which might ameliorate students＇ learning by adopting appropriate strategies for teaching.展开更多
This research collects 3896 errors made by 965 Chinese students in 5 junior middle schools in Xining and then a detailed analysis is made to discover the possible causes behind these errors.This research comes to the ...This research collects 3896 errors made by 965 Chinese students in 5 junior middle schools in Xining and then a detailed analysis is made to discover the possible causes behind these errors.This research comes to the following conclusions:first,during the course of English learning in junior middle school,the students make errors mainly in six specific areas:spelling,tenses,pronouns,verb“be”,articles,and numbers;second,the learners at an elementary level produce more interlingual errors than the learners at an advanced level.Third,error fossilization is serious.展开更多
A higher order boundary element method(HOBEM)is presented for inviscid flow passing cylinders in bounded or unbounded domain.The traditional boundary integral equation is established with respect to the velocity poten...A higher order boundary element method(HOBEM)is presented for inviscid flow passing cylinders in bounded or unbounded domain.The traditional boundary integral equation is established with respect to the velocity potential and its normal derivative.In present work,a new integral equation is derived for the tangential velocity.The boundary is discretized into higher order elements to ensure the continuity of slope at the element nodes.The velocity potential is also expanded with higher order shape functions,in which the unknown coefficients involve the tangential velocity.The expansion then ensures the continuities of the velocity and the slope of the boundary at element nodes.Through extensive comparison of the results for the analytical solution of cylinders,it is shown that the present HOBEM is much more accurate than the conventional BEM.展开更多
Lexical errors made by language learners frequently in the language learning process play a significant role in language teaching and learning. This paper, based on the theory of error analysis, mainly analyzes lexica...Lexical errors made by language learners frequently in the language learning process play a significant role in language teaching and learning. This paper, based on the theory of error analysis, mainly analyzes lexical errors made by Chinese senior one students in their writing and aims to find out the main types of lexical errors and the most frequent lexical errors in their writing. The results are of great significance and importance for language teaching and learning.展开更多
This article analyzes errors with regard to the types and causes of errors commonly committed by Chinese EFL(English as a foreign language)learners.It covers the concepts and theories concerning error analysis,synthes...This article analyzes errors with regard to the types and causes of errors commonly committed by Chinese EFL(English as a foreign language)learners.It covers the concepts and theories concerning error analysis,synthesizes previous research,as well as identifies the flaws and gaps found in those literatures.This article provides several teaching suggestions based on previous analyses,which have found that the misuse of verbs and articles are the most common errors in English writing among Chinese students.Based on this,most studies attributed those errors to the negative transfer of Chinese due to the thought patterns and disparities between Chinese and English.展开更多
Language teaching is not a one-way process.It interacts with language learning in an extremely intricate way.To improve language teaching,we need to take the process of language learning into account.This paper tries ...Language teaching is not a one-way process.It interacts with language learning in an extremely intricate way.To improve language teaching,we need to take the process of language learning into account.This paper tries to explore and understand what strategies the second language learners consciously or subconsciously adopt during their language learning process through the analyses of the linguistic errors they commit,so as to provide some insights into language teaching practice.展开更多
Based on error analysis, the influence of error sources on strapdown inertial navigation systems is discussed. And the maximum permissible component tolerances are established. In order to achieve the desired accuracy...Based on error analysis, the influence of error sources on strapdown inertial navigation systems is discussed. And the maximum permissible component tolerances are established. In order to achieve the desired accuracy (defined by circular error probability), the types of appropriate sensors are chosen. The inertial measurement unit (IMU) is composed of those sensors. It is necessary to calibrate the sensors to obtain their error model coefficients of IMU. After calibration tests, the accuracy is calculated by uniform design method and it is proved that the accuracy of IMU is satisfied for the desired goal.展开更多
[Objective] The aim was to explore the measurement of coordinate parameter by multi-baseline digital close-range photogrammetry system.[Method] The 3-dimensional coordinate of 8-year-old Jujube was measured by using L...[Objective] The aim was to explore the measurement of coordinate parameter by multi-baseline digital close-range photogrammetry system.[Method] The 3-dimensional coordinate of 8-year-old Jujube was measured by using Lensphoto multi-baseline digital close-range photogrammetry system,and through comparing with measured data of Total Station,the error and accuracy of photogrammetry data were analyzed.[Result] The absolute error of X,Y and Z coordinate was 0-0.014,0-0.018 and 0-0.004 m respectively,and the relative error of X,Y and Z coordinate was less than 0.145%.The significance test of pairs for the photogrammetry data and measured data of Total Station indicated that the space coordinate data of stumpage were accurately measured by using the multi-baseline digital close-range photogrammetry method,and the photogrammetry data meet the need of space coordinate measurement for virtual plant growth simulation.[Conclusion] This study had provided theoretical basis for the growth measurement of virtual plant growth simulation.展开更多
In order to monitor the working state of piston motor and measure its instantaneous rotation speed accurately, the measuring principle and method of instantaneous rotation speed based on industrial personal computer a...In order to monitor the working state of piston motor and measure its instantaneous rotation speed accurately, the measuring principle and method of instantaneous rotation speed based on industrial personal computer and data acquisition card are introduced, and the major error source, influence mechanism and processing method of data quantization error are dis- cussed. By means of hybrid programming approach of LabVIEW and MATLAB, the instantaneous rotation speed measurement system for the piston motor in variable speed hydraulic system is designed. The simulation and experimental results show that the designed instantaneous speed measurement system is feasible. Furthermore, the sampling frequency has an important influ- ence on the instantaneous rotation speed measurement of piston motor and higher sampling frequency can lower quantization er- ror and improve measurement accuracy.展开更多
As a field in applied linguistics, error analysis is not only an instrument for language acquisition research but also an auxiliary tool for language teaching. It plays a significant role both in exploring the learnin...As a field in applied linguistics, error analysis is not only an instrument for language acquisition research but also an auxiliary tool for language teaching. It plays a significant role both in exploring the learning rules and improving the teaching of foreign languages. With this information, teachers could adjust their teaching plan and make their teaching more effective. In this paper I present some common errors that my students make in their learning process. Based on these, a further elaboration on how to correct errors, including the attitudes to them, the integrative principles, the concrete methods and techniques for error correction is discussed as well.展开更多
This article develops an empirical an investigation on the errors in compositions written by students who are studying in Luzhou Vocational and Technical College （LVTC） and Luzhou Medical College （LMC） and contras...This article develops an empirical an investigation on the errors in compositions written by students who are studying in Luzhou Vocational and Technical College （LVTC） and Luzhou Medical College （LMC） and contrasts them in order to trace the source of the errors. It finally turns out to be that there exists strong correlation between students＇ academic quality and the number of errors of various types. Compared with ordinary university students, vocational and technical college （VTC） students＇ interlanguage （IL） errors seem to be more rudimental, and more negative-transferring, most of which are influenced by their mother tongue （MT）-Chinese. VTC students＇ general error in writing is misspelling, while university students ＇ major error lies in collocation. In this thesis, some practical enlightenment about learning and teaching English writing are also proposed.展开更多
A Chebyshev fitting way for a propeller atlas across four quadrants is discussed. As an example, Chebyshev polynomial fitting results and its error analysis are given. Because it’s difficult generally to get a propel...A Chebyshev fitting way for a propeller atlas across four quadrants is discussed. As an example, Chebyshev polynomial fitting results and its error analysis are given. Because it’s difficult generally to get a propeller atlas across four quadrants, a way is used to construct an alternative with higher accuracy based on the properties. As an application example, an alternative for the propeller property of a Deep Submergence Vehicle across four quadrants is given practically and a simulation model of the four quadrants propeller for dynamic condition is set up. The model lays a foundation for DSV full operating-condition movement simulation. A lot of simulation work shows that the results are very close to the practical data and, therefore, are effective.展开更多
A three-dimensional wind field analysis sollware based on the Beigng-Gucheng dual-Doppler weather radar system has been built, and evaluated by using the numerical cloud model producing storm flow and hydrometeor fiel...A three-dimensional wind field analysis sollware based on the Beigng-Gucheng dual-Doppler weather radar system has been built, and evaluated by using the numerical cloud model producing storm flow and hydrometeor fields. The effects of observation noise and the spatial distribution of wind field analysis error are also investigated.展开更多
Compensating for photovoltaic(PV)power forecast errors is an important function of energy storage systems.As PV power outputs have strong random fluctuations and uncertainty,it is difficult to satisfy the grid-connect...Compensating for photovoltaic(PV)power forecast errors is an important function of energy storage systems.As PV power outputs have strong random fluctuations and uncertainty,it is difficult to satisfy the grid-connection requirements using fixed energy storage capacity configuration methods.In this paper,a method of configuring energy storage capacity is proposed based on the uncertainty of PV power generation.A k-means clustering algorithm is used to classify weather types based on differences in solar irradiance.The power forecast errors in different weather types are analyzed,and an energy storage system is used to compensate for the errors.The kernel density estimation is used to fit the distributions of the daily maximum power and maximum capacity requirements of the energy storage system;the power and capacity of the energy storage unit are calculated at different confidence levels.The optimized energy storage configuration of a PV plant is presented according to the calculated degrees of power and capacity satisfaction.The proposed method was validated using actual operating data from a PV power station.The results indicated that the required energy storage can be significantly reduced while compensating for power forecast errors.展开更多
文摘This paper analyzes the errors in Chinese college students＇ compositions. The study finds that among the three types of errors： interference errors, intralingual errors and developmental errors, developmental errors are the most important errors in the Chinese college students＇ writing. The results will help Chinese EFL teachers （especially college teachers） and students better judge the errors in the English writings of the Chinese students. It will also help the students avoid different kinds of errors in English writing.
基金supported by the National Natural Science Foundation of China(No.U2142206).
文摘Numerical weather prediction(NWP)models have always presented large forecasting errors of surface wind speeds over regions with complex terrain.In this study,surface wind forecasts from an operational NWP model,the SMS-WARR(Shanghai Meteorological Service-WRF ADAS Rapid Refresh System),are analyzed to quantitatively reveal the relationships between the forecasted surface wind speed errors and terrain features,with the intent of providing clues to better apply the NWP model to complex terrain regions.The terrain features are described by three parameters:the standard deviation of the model grid-scale orography,terrain height error of the model,and slope angle.The results show that the forecast bias has a unimodal distribution with a change in the standard deviation of orography.The minimum ME(the mean value of bias)is 1.2 m s^(-1) when the standard deviation is between 60 and 70 m.A positive correlation exists between bias and terrain height error,with the ME increasing by 10%−30%for every 200 m increase in terrain height error.The ME decreases by 65.6%when slope angle increases from(0.5°−1.5°)to larger than 3.5°for uphill winds but increases by 35.4%when the absolute value of slope angle increases from(0.5°−1.5°)to(2.5°−3.5°)for downhill winds.Several sensitivity experiments are carried out with a model output statistical(MOS)calibration model for surface wind speeds and ME(RMSE)has been reduced by 90%(30%)by introducing terrain parameters,demonstrating the value of this study.
基金Supported by the Indigenous Innovation’s Capability Development Program of Huizhou University(HZU202003,HZU202020)Natural Science Foundation of Guangdong Province(2022A1515011463)+2 种基金the Project of Educational Commission of Guangdong Province(2023ZDZX1025)National Natural Science Foundation of China(12271473)Guangdong Province’s 2023 Education Science Planning Project(Higher Education Special Project)(2023GXJK505)。
文摘Complementary-label learning(CLL)aims at finding a classifier via samples with complementary labels.Such data is considered to contain less information than ordinary-label samples.The transition matrix between the true label and the complementary label,and some loss functions have been developed to handle this problem.In this paper,we show that CLL can be transformed into ordinary classification under some mild conditions,which indicates that the complementary labels can supply enough information in most cases.As an example,an extensive misclassification error analysis was performed for the Kernel Ridge Regression(KRR)method applied to multiple complementary-label learning(MCLL),which demonstrates its superior performance compared to existing approaches.
文摘Chinese non-English majors are a large group of English learners.In the process of English pronunciation acquisition,issues such as incomplete phonological knowledge,transfer of mother tongue,and overgeneralization,lead to confusion of phonemes and stress,misunderstanding of syllable structure,and errors of assimilation,drop,and epenthesis.The accuracy of English pronunciation can only be improved by knowing both English and Chinese phonological systems,strengthening the teaching of English phonological knowledge,and adopting various phonological training activities.
文摘Before cognitive approach came into being in the 1960s, errors in L2 learning were always regarded as signs of failure which needed immediate attention from the teacher. By analyzing a student＇s writing, this paper tries to elaborate on the roles that errors can play in L2 learning process.
文摘English is considered as Arab students＇ second language which is not used frequently in their daily conversations. Since writing in English is a challenging experience for Omani students, errors in grammar and sentence structures were identified in bridging language courses （foundation level 2） in the field of ESL （English as a Second Language}. Learners＇ errors were considered positively as the best sources to identify students＇ limitations in English writing. The present study investigates the structure errors of Omani students＇ writings in English in foundation level 2 at Arab Open University. The focal aim is to study the errors that Ornani students commit when they are using adjectives ＋ nouns, indefinite articles, and subordinate conjunction ＂because＂. Results show that Omani students committed the following common errors： misplacement of adjectives, omission of the indefinite articles, and wrong structure of the subordinate conjunction （because）. The prime aim of this study is to examine the students＇ aforementioned structural errors which are the result of the interference of their mother-tongue. In order to achieve these aims, students were asked to write two different topics. Finally, this research suggests further recommendations for further studies which might ameliorate students＇ learning by adopting appropriate strategies for teaching.
文摘This research collects 3896 errors made by 965 Chinese students in 5 junior middle schools in Xining and then a detailed analysis is made to discover the possible causes behind these errors.This research comes to the following conclusions:first,during the course of English learning in junior middle school,the students make errors mainly in six specific areas:spelling,tenses,pronouns,verb“be”,articles,and numbers;second,the learners at an elementary level produce more interlingual errors than the learners at an advanced level.Third,error fossilization is serious.
基金financially supported by the National Natural Science Foundation of China (Grant Nos.52271276,52271319,and 52201364)the Natural Science Foundation of Jiangsu Province (Grant No.BK20201006)。
文摘A higher order boundary element method(HOBEM)is presented for inviscid flow passing cylinders in bounded or unbounded domain.The traditional boundary integral equation is established with respect to the velocity potential and its normal derivative.In present work,a new integral equation is derived for the tangential velocity.The boundary is discretized into higher order elements to ensure the continuity of slope at the element nodes.The velocity potential is also expanded with higher order shape functions,in which the unknown coefficients involve the tangential velocity.The expansion then ensures the continuities of the velocity and the slope of the boundary at element nodes.Through extensive comparison of the results for the analytical solution of cylinders,it is shown that the present HOBEM is much more accurate than the conventional BEM.
文摘Lexical errors made by language learners frequently in the language learning process play a significant role in language teaching and learning. This paper, based on the theory of error analysis, mainly analyzes lexical errors made by Chinese senior one students in their writing and aims to find out the main types of lexical errors and the most frequent lexical errors in their writing. The results are of great significance and importance for language teaching and learning.
文摘This article analyzes errors with regard to the types and causes of errors commonly committed by Chinese EFL(English as a foreign language)learners.It covers the concepts and theories concerning error analysis,synthesizes previous research,as well as identifies the flaws and gaps found in those literatures.This article provides several teaching suggestions based on previous analyses,which have found that the misuse of verbs and articles are the most common errors in English writing among Chinese students.Based on this,most studies attributed those errors to the negative transfer of Chinese due to the thought patterns and disparities between Chinese and English.
文摘Language teaching is not a one-way process.It interacts with language learning in an extremely intricate way.To improve language teaching,we need to take the process of language learning into account.This paper tries to explore and understand what strategies the second language learners consciously or subconsciously adopt during their language learning process through the analyses of the linguistic errors they commit,so as to provide some insights into language teaching practice.
文摘Based on error analysis, the influence of error sources on strapdown inertial navigation systems is discussed. And the maximum permissible component tolerances are established. In order to achieve the desired accuracy (defined by circular error probability), the types of appropriate sensors are chosen. The inertial measurement unit (IMU) is composed of those sensors. It is necessary to calibrate the sensors to obtain their error model coefficients of IMU. After calibration tests, the accuracy is calculated by uniform design method and it is proved that the accuracy of IMU is satisfied for the desired goal.
基金Supported by National Natural Science Foundation of China(30770401)National Eleventh Five-Year Plan for Forestry Scienceand Technology Support Topics(2006BADO3A0505)~~
文摘[Objective] The aim was to explore the measurement of coordinate parameter by multi-baseline digital close-range photogrammetry system.[Method] The 3-dimensional coordinate of 8-year-old Jujube was measured by using Lensphoto multi-baseline digital close-range photogrammetry system,and through comparing with measured data of Total Station,the error and accuracy of photogrammetry data were analyzed.[Result] The absolute error of X,Y and Z coordinate was 0-0.014,0-0.018 and 0-0.004 m respectively,and the relative error of X,Y and Z coordinate was less than 0.145%.The significance test of pairs for the photogrammetry data and measured data of Total Station indicated that the space coordinate data of stumpage were accurately measured by using the multi-baseline digital close-range photogrammetry method,and the photogrammetry data meet the need of space coordinate measurement for virtual plant growth simulation.[Conclusion] This study had provided theoretical basis for the growth measurement of virtual plant growth simulation.
基金National Natural Science Foundation of China(No.51275375,No.51509006)Shaanxi Provincial Natural Science Basic Research Plan(No.2014JQ7246)+1 种基金The Science and Technology of Hubei Province(No.B2015115)Doctoral Research Foundation of Hubei University of Automotive Technology(No.BK201403)
文摘In order to monitor the working state of piston motor and measure its instantaneous rotation speed accurately, the measuring principle and method of instantaneous rotation speed based on industrial personal computer and data acquisition card are introduced, and the major error source, influence mechanism and processing method of data quantization error are dis- cussed. By means of hybrid programming approach of LabVIEW and MATLAB, the instantaneous rotation speed measurement system for the piston motor in variable speed hydraulic system is designed. The simulation and experimental results show that the designed instantaneous speed measurement system is feasible. Furthermore, the sampling frequency has an important influ- ence on the instantaneous rotation speed measurement of piston motor and higher sampling frequency can lower quantization er- ror and improve measurement accuracy.
文摘As a field in applied linguistics, error analysis is not only an instrument for language acquisition research but also an auxiliary tool for language teaching. It plays a significant role both in exploring the learning rules and improving the teaching of foreign languages. With this information, teachers could adjust their teaching plan and make their teaching more effective. In this paper I present some common errors that my students make in their learning process. Based on these, a further elaboration on how to correct errors, including the attitudes to them, the integrative principles, the concrete methods and techniques for error correction is discussed as well.
文摘This article develops an empirical an investigation on the errors in compositions written by students who are studying in Luzhou Vocational and Technical College （LVTC） and Luzhou Medical College （LMC） and contrasts them in order to trace the source of the errors. It finally turns out to be that there exists strong correlation between students＇ academic quality and the number of errors of various types. Compared with ordinary university students, vocational and technical college （VTC） students＇ interlanguage （IL） errors seem to be more rudimental, and more negative-transferring, most of which are influenced by their mother tongue （MT）-Chinese. VTC students＇ general error in writing is misspelling, while university students ＇ major error lies in collocation. In this thesis, some practical enlightenment about learning and teaching English writing are also proposed.
文摘A Chebyshev fitting way for a propeller atlas across four quadrants is discussed. As an example, Chebyshev polynomial fitting results and its error analysis are given. Because it’s difficult generally to get a propeller atlas across four quadrants, a way is used to construct an alternative with higher accuracy based on the properties. As an application example, an alternative for the propeller property of a Deep Submergence Vehicle across four quadrants is given practically and a simulation model of the four quadrants propeller for dynamic condition is set up. The model lays a foundation for DSV full operating-condition movement simulation. A lot of simulation work shows that the results are very close to the practical data and, therefore, are effective.
文摘A three-dimensional wind field analysis sollware based on the Beigng-Gucheng dual-Doppler weather radar system has been built, and evaluated by using the numerical cloud model producing storm flow and hydrometeor fields. The effects of observation noise and the spatial distribution of wind field analysis error are also investigated.
基金supported by Nation Key R&D Program of China(2021YFE0102400).
文摘Compensating for photovoltaic(PV)power forecast errors is an important function of energy storage systems.As PV power outputs have strong random fluctuations and uncertainty,it is difficult to satisfy the grid-connection requirements using fixed energy storage capacity configuration methods.In this paper,a method of configuring energy storage capacity is proposed based on the uncertainty of PV power generation.A k-means clustering algorithm is used to classify weather types based on differences in solar irradiance.The power forecast errors in different weather types are analyzed,and an energy storage system is used to compensate for the errors.The kernel density estimation is used to fit the distributions of the daily maximum power and maximum capacity requirements of the energy storage system;the power and capacity of the energy storage unit are calculated at different confidence levels.The optimized energy storage configuration of a PV plant is presented according to the calculated degrees of power and capacity satisfaction.The proposed method was validated using actual operating data from a PV power station.The results indicated that the required energy storage can be significantly reduced while compensating for power forecast errors.
