Pub Date : 2010-11-09DOI: 10.1109/ICHQP.2010.5625412
V. Gosbell, R. Barr
Present IEC guidelines are difficult to apply to realistic cases because of the data load, the number of assumptions required and the computational complexity. A new approach is given based on the concept of voltage droop, to be detailed in a companion paper. The benefits of the approach are a simple calculation with minimal data and no required assumptions. It applies to radial or meshed distribution systems where feeders are sufficiently short that line capacitance can be ignored. The approach can be applied at the installation (MV or LV) and the equipment level and can be used to give reference values for equipment emission standards.
{"title":"Harmonic allocation following IEC guidelines using the voltage droop concept","authors":"V. Gosbell, R. Barr","doi":"10.1109/ICHQP.2010.5625412","DOIUrl":"https://doi.org/10.1109/ICHQP.2010.5625412","url":null,"abstract":"Present IEC guidelines are difficult to apply to realistic cases because of the data load, the number of assumptions required and the computational complexity. A new approach is given based on the concept of voltage droop, to be detailed in a companion paper. The benefits of the approach are a simple calculation with minimal data and no required assumptions. It applies to radial or meshed distribution systems where feeders are sufficiently short that line capacitance can be ignored. The approach can be applied at the installation (MV or LV) and the equipment level and can be used to give reference values for equipment emission standards.","PeriodicalId":180078,"journal":{"name":"Proceedings of 14th International Conference on Harmonics and Quality of Power - ICHQP 2010","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121119108","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-11-09DOI: 10.1109/ICHQP.2010.5625393
R. Vianello, M. O. Prates, C. Duque, Augusto S. Cequeira, P. M. da Silveira, P. Ribeiro
This paper proposes the use of Artificial Neural Networks (ANN) to estimate the magnitude and phase of fundamental component of sinusoidal signals in the presence of harmonics, sub-harmonics and DC offset. The proposed methodology uses a preprocessing that is able to generate a signal that represents the influence of sub-harmonics and DC offset in the fundamental component. This signal is used as input of ANN, which estimate the influence of that signal in quadrature components. Using this information, corrections can be made in quadrature components then the real value of phasor of the fundamental component is estimated. The performance of the proposed algorithm was compared with classical methods such as DFT, using one and two cycles, and LES. The results showed that the proposed method is accurate and fast. The methodology can be used as a phasor estimator of system with poor Power Quality indices for monitoring, control and protection applications.
{"title":"New phasor estimator in the presence of harmonics, dc offset, and interharmonics","authors":"R. Vianello, M. O. Prates, C. Duque, Augusto S. Cequeira, P. M. da Silveira, P. Ribeiro","doi":"10.1109/ICHQP.2010.5625393","DOIUrl":"https://doi.org/10.1109/ICHQP.2010.5625393","url":null,"abstract":"This paper proposes the use of Artificial Neural Networks (ANN) to estimate the magnitude and phase of fundamental component of sinusoidal signals in the presence of harmonics, sub-harmonics and DC offset. The proposed methodology uses a preprocessing that is able to generate a signal that represents the influence of sub-harmonics and DC offset in the fundamental component. This signal is used as input of ANN, which estimate the influence of that signal in quadrature components. Using this information, corrections can be made in quadrature components then the real value of phasor of the fundamental component is estimated. The performance of the proposed algorithm was compared with classical methods such as DFT, using one and two cycles, and LES. The results showed that the proposed method is accurate and fast. The methodology can be used as a phasor estimator of system with poor Power Quality indices for monitoring, control and protection applications.","PeriodicalId":180078,"journal":{"name":"Proceedings of 14th International Conference on Harmonics and Quality of Power - ICHQP 2010","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127117481","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-11-09DOI: 10.1109/ICHQP.2010.5625466
A. Bracale, G. Carpinelli, P. Caramia, A. Russo, P. Varilone
In this paper, the point estimate method is applied to account for the uncertainties that affect the evaluation of the steady state operating conditions of an unbalanced three-phase power system in the presence of wind farms. The accuracy of the proposed technique is tested on the three-phase unbalanced IEEE 34-bus test system adequately modified to take into account the presence of wind farms; the results obtained by applying the Monte Carlo simulation are assumed as a reference. The main conclusion is that the point estimate method gives good solutions in terms of accuracy and computational efforts.
{"title":"Point estimate schemes for probabilistic load flow analysis of unbalanced electrical distribution systems with wind farms","authors":"A. Bracale, G. Carpinelli, P. Caramia, A. Russo, P. Varilone","doi":"10.1109/ICHQP.2010.5625466","DOIUrl":"https://doi.org/10.1109/ICHQP.2010.5625466","url":null,"abstract":"In this paper, the point estimate method is applied to account for the uncertainties that affect the evaluation of the steady state operating conditions of an unbalanced three-phase power system in the presence of wind farms. The accuracy of the proposed technique is tested on the three-phase unbalanced IEEE 34-bus test system adequately modified to take into account the presence of wind farms; the results obtained by applying the Monte Carlo simulation are assumed as a reference. The main conclusion is that the point estimate method gives good solutions in terms of accuracy and computational efforts.","PeriodicalId":180078,"journal":{"name":"Proceedings of 14th International Conference on Harmonics and Quality of Power - ICHQP 2010","volume":"2008 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127318186","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-11-09DOI: 10.1109/ICHQP.2010.5625331
V. Musolino, L. Piegari, E. Tironi, L. Martini, A. Brambilla, C. Tornelli
The growing diffusion of distributed energy sources is making higher and higher the attention for DC distribution networks, that present some advantages related to an easier integration of renewable energy sources, storage systems and electrical drives. The DC network has to be connected to the traditional AC network by means of a converter interface whose main scope is the regulation of the power fluxes exchanged between the two networks. In this paper it is shown how it is possible to reduce flicker phenomenon, appearing when a pulsing load is connected on the DC network, controlling the front-end converter and using a storage system connected to the DC line. Numerical simulation results have been carried out to prove this capability. Moreover some preliminary experimental tests, realized on a test facility under construction at ERSE, have been performed and results are reported.
{"title":"Simulations and field test results for potential applications of LV DC distribution network to reduce flicker effect","authors":"V. Musolino, L. Piegari, E. Tironi, L. Martini, A. Brambilla, C. Tornelli","doi":"10.1109/ICHQP.2010.5625331","DOIUrl":"https://doi.org/10.1109/ICHQP.2010.5625331","url":null,"abstract":"The growing diffusion of distributed energy sources is making higher and higher the attention for DC distribution networks, that present some advantages related to an easier integration of renewable energy sources, storage systems and electrical drives. The DC network has to be connected to the traditional AC network by means of a converter interface whose main scope is the regulation of the power fluxes exchanged between the two networks. In this paper it is shown how it is possible to reduce flicker phenomenon, appearing when a pulsing load is connected on the DC network, controlling the front-end converter and using a storage system connected to the DC line. Numerical simulation results have been carried out to prove this capability. Moreover some preliminary experimental tests, realized on a test facility under construction at ERSE, have been performed and results are reported.","PeriodicalId":180078,"journal":{"name":"Proceedings of 14th International Conference on Harmonics and Quality of Power - ICHQP 2010","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125112712","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-11-09DOI: 10.1109/ICHQP.2010.5625458
G. Todeschini
The present paper investigates the performance of a Wind Energy Conversion System controlled to operate as an Active Filter when unbalanced loads are supplied by the same feeder. The control strategy named ‘compensation by means of Combined Modulation’ [1] is applied. This control methodology has been designed to sink the harmonic currents injected by balanced Non-Linear Load, and the connection of unbalanced loads to the PCC results in additional harmonic current flows within the WECS components and other detrimental effects. This paper is intended to analyze these effects and to determine the unbalanced load conditions that can be withstood by the WECS without compromising the components' integrity.
{"title":"Wind Energy Conversion Systems as active filters under unbalanced load conditions","authors":"G. Todeschini","doi":"10.1109/ICHQP.2010.5625458","DOIUrl":"https://doi.org/10.1109/ICHQP.2010.5625458","url":null,"abstract":"The present paper investigates the performance of a Wind Energy Conversion System controlled to operate as an Active Filter when unbalanced loads are supplied by the same feeder. The control strategy named ‘compensation by means of Combined Modulation’ [1] is applied. This control methodology has been designed to sink the harmonic currents injected by balanced Non-Linear Load, and the connection of unbalanced loads to the PCC results in additional harmonic current flows within the WECS components and other detrimental effects. This paper is intended to analyze these effects and to determine the unbalanced load conditions that can be withstood by the WECS without compromising the components' integrity.","PeriodicalId":180078,"journal":{"name":"Proceedings of 14th International Conference on Harmonics and Quality of Power - ICHQP 2010","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115051907","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-11-09DOI: 10.1109/ICHQP.2010.5625398
M. Parentoni, J. Abreu, F. Belchior
The objective of this paper is to present a procedure, experimentally developed, for dimensioning transformers submitted to nonlinear loads conditions. The method is based on the record of the heating curve of the electrical equipment. First of all, the increase of losses in transformers is obtained for several situations of current distortion in transformer windings. Moreover, the increase of losses is divided into two parts: the first corresponding to the increase of the true rms current for the same active power of an equivalent linear load; and the second corresponding to the increase of additional losses in the windings due to skin effect. The results, for each situation of harmonic distortion, are used to obtain the transformer design which, finally, is compared with the transformer design obtained through the theoretical procedure based on IEEE Std C57.110-1998.
{"title":"Design proposition of transformers used for feeding nonlinear loads — A practical approach based on temperature measurement","authors":"M. Parentoni, J. Abreu, F. Belchior","doi":"10.1109/ICHQP.2010.5625398","DOIUrl":"https://doi.org/10.1109/ICHQP.2010.5625398","url":null,"abstract":"The objective of this paper is to present a procedure, experimentally developed, for dimensioning transformers submitted to nonlinear loads conditions. The method is based on the record of the heating curve of the electrical equipment. First of all, the increase of losses in transformers is obtained for several situations of current distortion in transformer windings. Moreover, the increase of losses is divided into two parts: the first corresponding to the increase of the true rms current for the same active power of an equivalent linear load; and the second corresponding to the increase of additional losses in the windings due to skin effect. The results, for each situation of harmonic distortion, are used to obtain the transformer design which, finally, is compared with the transformer design obtained through the theoretical procedure based on IEEE Std C57.110-1998.","PeriodicalId":180078,"journal":{"name":"Proceedings of 14th International Conference on Harmonics and Quality of Power - ICHQP 2010","volume":"63 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115532313","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-11-09DOI: 10.1109/ICHQP.2010.5625472
Carlo Masetti
The paper describes the process of revision of European Standard EN 50160 on voltage characteristics of electricity supplied by public distribution networks, with a consequent evaluation of the Italian situation.
{"title":"Revision of European Standard EN 50160 on power quality: Reasons and solutions","authors":"Carlo Masetti","doi":"10.1109/ICHQP.2010.5625472","DOIUrl":"https://doi.org/10.1109/ICHQP.2010.5625472","url":null,"abstract":"The paper describes the process of revision of European Standard EN 50160 on voltage characteristics of electricity supplied by public distribution networks, with a consequent evaluation of the Italian situation.","PeriodicalId":180078,"journal":{"name":"Proceedings of 14th International Conference on Harmonics and Quality of Power - ICHQP 2010","volume":"100 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122838825","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-11-09DOI: 10.1109/ICHQP.2010.5625402
J. Desmet, G. Vanalme, C. Debruyne, L. Vandevelde
Nowadays, both industrial and residential consumers use power electronics with the aim of rational use of energy or the implementation of distributed generation. However, power electronics may cause harmonic currents. Since cable losses are function of the rms current, harmonic currents will increase cable losses. This contribution analyses the influence of the current harmonic spectrum on low voltage cable losses. Grid configurations are discussed with the aim to optimize cable joule losses in case of nonlinear load conditions.
{"title":"Influence of harmonic currents on cable losses for different grid configurations","authors":"J. Desmet, G. Vanalme, C. Debruyne, L. Vandevelde","doi":"10.1109/ICHQP.2010.5625402","DOIUrl":"https://doi.org/10.1109/ICHQP.2010.5625402","url":null,"abstract":"Nowadays, both industrial and residential consumers use power electronics with the aim of rational use of energy or the implementation of distributed generation. However, power electronics may cause harmonic currents. Since cable losses are function of the rms current, harmonic currents will increase cable losses. This contribution analyses the influence of the current harmonic spectrum on low voltage cable losses. Grid configurations are discussed with the aim to optimize cable joule losses in case of nonlinear load conditions.","PeriodicalId":180078,"journal":{"name":"Proceedings of 14th International Conference on Harmonics and Quality of Power - ICHQP 2010","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128288400","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-11-09DOI: 10.1109/ICHQP.2010.5625480
Yao Xiao, Xavier Yang
The summation of two harmonic voltage vectors at same frequency is only certain if their amplitudes and phase angles are well known. Therefore, there are many cases where the difference of phase angles between harmonic voltage vectors is unknown. In calculation of the steady state rating of the a.c. harmonic filter equipment, algebraic summation method is often used in determining maximal harmonic level. This summation law is very conservative as it may result in high cost of equipment ratings. Actually, a compromise should be made in taking into account the equipment safety and the risk of overrating as well as excessive costs. Based on uniform distribution of difference in phase angles, the paper provides an algorithm to calculate the probability upon which the magnitude of summation vector of two harmonic voltages may exceed a given value. This result may be applied in passive harmonic filter design in order to cut down the excessive over cost, and may be served as harmonic assessment guidance used in evaluating and setting grid power quality commitment.
{"title":"A grid harmonic summation method based on the probability assessment of harmonic phase angles","authors":"Yao Xiao, Xavier Yang","doi":"10.1109/ICHQP.2010.5625480","DOIUrl":"https://doi.org/10.1109/ICHQP.2010.5625480","url":null,"abstract":"The summation of two harmonic voltage vectors at same frequency is only certain if their amplitudes and phase angles are well known. Therefore, there are many cases where the difference of phase angles between harmonic voltage vectors is unknown. In calculation of the steady state rating of the a.c. harmonic filter equipment, algebraic summation method is often used in determining maximal harmonic level. This summation law is very conservative as it may result in high cost of equipment ratings. Actually, a compromise should be made in taking into account the equipment safety and the risk of overrating as well as excessive costs. Based on uniform distribution of difference in phase angles, the paper provides an algorithm to calculate the probability upon which the magnitude of summation vector of two harmonic voltages may exceed a given value. This result may be applied in passive harmonic filter design in order to cut down the excessive over cost, and may be served as harmonic assessment guidance used in evaluating and setting grid power quality commitment.","PeriodicalId":180078,"journal":{"name":"Proceedings of 14th International Conference on Harmonics and Quality of Power - ICHQP 2010","volume":"119 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130374419","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-11-09DOI: 10.1109/ICHQP.2010.5625434
S. Zajaczek, L. Skrivanek, L. Ivanek
The paper deals with finding the optimal shape of the electromagnet by changing skew keeper and skew pole shoe of the electromagnet so as to obtain maximum tensile force. The solution used numerical methods, especially the program COMSOL.
{"title":"Shape optimization of electromagnet","authors":"S. Zajaczek, L. Skrivanek, L. Ivanek","doi":"10.1109/ICHQP.2010.5625434","DOIUrl":"https://doi.org/10.1109/ICHQP.2010.5625434","url":null,"abstract":"The paper deals with finding the optimal shape of the electromagnet by changing skew keeper and skew pole shoe of the electromagnet so as to obtain maximum tensile force. The solution used numerical methods, especially the program COMSOL.","PeriodicalId":180078,"journal":{"name":"Proceedings of 14th International Conference on Harmonics and Quality of Power - ICHQP 2010","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114825402","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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