Pub Date : 2006-10-01DOI: 10.1109/ICPST.2006.321420
Justin-Jin Zhang, Qianjin Liu, C. Rehtan, S. Rudin
New challenges are rising with the fast development of power grids in mega cities, especially huge short circuit current levels and reduced voltage stability. In this paper, two solutions based on new technologies are proposed. The first solution consists of a new short circuit fault current limiter (called DYNACUR) together with STATCOMs (called SVC Light). Another consists of voltage source converter based HVDC (HVDC Light) together with a small short circuit fault current limiter(DYNACUR). The schemes and their corresponding performances are investigated based on a mega city power grid similar to Shanghai. The results show that both proposed solutions are effective. The costs and benefits are compared related to the approximate performance. Finally, two real cases of STATCOMs and HVDC Light are introduced briefly.
{"title":"Investigation of several new technologies for mega city power grid issues","authors":"Justin-Jin Zhang, Qianjin Liu, C. Rehtan, S. Rudin","doi":"10.1109/ICPST.2006.321420","DOIUrl":"https://doi.org/10.1109/ICPST.2006.321420","url":null,"abstract":"New challenges are rising with the fast development of power grids in mega cities, especially huge short circuit current levels and reduced voltage stability. In this paper, two solutions based on new technologies are proposed. The first solution consists of a new short circuit fault current limiter (called DYNACUR) together with STATCOMs (called SVC Light). Another consists of voltage source converter based HVDC (HVDC Light) together with a small short circuit fault current limiter(DYNACUR). The schemes and their corresponding performances are investigated based on a mega city power grid similar to Shanghai. The results show that both proposed solutions are effective. The costs and benefits are compared related to the approximate performance. Finally, two real cases of STATCOMs and HVDC Light are introduced briefly.","PeriodicalId":181574,"journal":{"name":"2006 International Conference on Power System Technology","volume":"141 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116614863","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 : 2006-10-01DOI: 10.1109/ICPST.2006.321429
L. Yingying, Liao Guodong, Gu Qiang, Xu Yonghai
The power quality comprehensive evaluation (PQCE) is the foundation of deciding the price according to the quality of power commodity as well as a part of the ancillary service in power market. A new method based on the radial basis function (RBF) neural network for PQCE is proposed in the paper. According to the national standards of P.R. China, this paper made the grades of each power quality index. Efficient samples based on the random-distribution theory were produced to train the network The RBF neural network with high non-linearity-fitting capacity was applied to the PQCE, which overcame the shortages such as uncertainty and man-influenced in fuzzy mathematics, probability and mathematical statistics and analytic hierarchy process (AHP). The RBF neural network-based model possessed the objective and rationalization. The practical example for PQCE on the substations approved that the proposed approach is reasonable and feasible.
{"title":"Radial Basis Function Neural Network Based Comprehensive Evaluation for Power Quality","authors":"L. Yingying, Liao Guodong, Gu Qiang, Xu Yonghai","doi":"10.1109/ICPST.2006.321429","DOIUrl":"https://doi.org/10.1109/ICPST.2006.321429","url":null,"abstract":"The power quality comprehensive evaluation (PQCE) is the foundation of deciding the price according to the quality of power commodity as well as a part of the ancillary service in power market. A new method based on the radial basis function (RBF) neural network for PQCE is proposed in the paper. According to the national standards of P.R. China, this paper made the grades of each power quality index. Efficient samples based on the random-distribution theory were produced to train the network The RBF neural network with high non-linearity-fitting capacity was applied to the PQCE, which overcame the shortages such as uncertainty and man-influenced in fuzzy mathematics, probability and mathematical statistics and analytic hierarchy process (AHP). The RBF neural network-based model possessed the objective and rationalization. The practical example for PQCE on the substations approved that the proposed approach is reasonable and feasible.","PeriodicalId":181574,"journal":{"name":"2006 International Conference on Power System Technology","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116819833","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 : 2006-10-01DOI: 10.1109/ICPST.2006.321422
L. Barthold
This paper shows how, with simple modifications using either conventional or bidirectional valves, bipole and monopole systems can be connected in parallel and operated as a three pole configuration in which no earth return current flows in either normal or pole-out conditions. While slightly less efficient in terms of equipment utilization, the system reduces line losses for a given MW transfer and has better overload and internal redundancy; both of which enhance (n-1)-constrained loading of the parallel ac system. Because it makes full thermal use of three conductors, the tripole system improves both the technical and economic cases for converting existing three-phase ac lines to dc. Doing so increases power transfer much more than is possible with compensation or phase shifting transformers. The paper reviews the basic principles inherent in the tripole HVDC system and compares characteristics of both bipole and tripole alternatives in the context of an ac network.
{"title":"Technical and Economic Aspects of Tripole HVDC","authors":"L. Barthold","doi":"10.1109/ICPST.2006.321422","DOIUrl":"https://doi.org/10.1109/ICPST.2006.321422","url":null,"abstract":"This paper shows how, with simple modifications using either conventional or bidirectional valves, bipole and monopole systems can be connected in parallel and operated as a three pole configuration in which no earth return current flows in either normal or pole-out conditions. While slightly less efficient in terms of equipment utilization, the system reduces line losses for a given MW transfer and has better overload and internal redundancy; both of which enhance (n-1)-constrained loading of the parallel ac system. Because it makes full thermal use of three conductors, the tripole system improves both the technical and economic cases for converting existing three-phase ac lines to dc. Doing so increases power transfer much more than is possible with compensation or phase shifting transformers. The paper reviews the basic principles inherent in the tripole HVDC system and compares characteristics of both bipole and tripole alternatives in the context of an ac network.","PeriodicalId":181574,"journal":{"name":"2006 International Conference on Power System Technology","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128759147","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 : 2006-10-01DOI: 10.1109/ICPST.2006.321613
Shi-jia Tang, Gaolin Wu, Hua Yin
Ground flash density (flashs/km2 /year) can reflect the activity of lightning exactly, so it was presented in this paper as a principle to show the thunder distribution in Chongqing region. Based on this principle, thunderstorm distribution electronic map of Chongqing region was programmed, using the data accumulated by the lightning location system in recent years. And this electronic map will be used in the lightning-proof of power transmission lines.
{"title":"Study of Ground Flash Density","authors":"Shi-jia Tang, Gaolin Wu, Hua Yin","doi":"10.1109/ICPST.2006.321613","DOIUrl":"https://doi.org/10.1109/ICPST.2006.321613","url":null,"abstract":"Ground flash density (flashs/km2 /year) can reflect the activity of lightning exactly, so it was presented in this paper as a principle to show the thunder distribution in Chongqing region. Based on this principle, thunderstorm distribution electronic map of Chongqing region was programmed, using the data accumulated by the lightning location system in recent years. And this electronic map will be used in the lightning-proof of power transmission lines.","PeriodicalId":181574,"journal":{"name":"2006 International Conference on Power System Technology","volume":"105 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128256218","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 : 2006-10-01DOI: 10.1109/ICPST.2006.321534
C. Thitithamrongchai, B. Eua‐arporn
This paper presents an efficient method for solving economic load dispatch (ELD) problems using a hybrid self- adaptive differential evolution with augmented Lagrange multiplier method (SADE_ALM). Treated as additional control variables, two strategic parameters called the mutation factor (F) and the crossover constant (CR) are dynamically self-adaptive throughout the evolutionary process. Since tuning of the parameters is a tedious task due to complex relationship among parameters, the optimal parameter settings may never be found, and possibly leads to a local optimal solution. An augmented lagrange multiplier method (ALM) is applied to handle equality/inequality constraints. To demonstrate the effectiveness of the proposed algorithm, two ELD problems considering: (1) multiple fuels, and (2) multiple fuels with valve-point effects, are tested and compared with other methods e.g. differential evolution (DE) based methods, modified particle swarm optimization (MPSO), improved genetic algorithm with multiplier updating (IGA_MU) etc. The results show that the proposed SADE_ALM is very effective and provides promising capability for solving the economic load dispatch problem with piecewise quadratic cost function.
{"title":"Economic Load Dispatch for Piecewise Quadratic Cost Function using Hybrid Self-adaptive Differential Evolution with Augmented Lagrange Multiplier Method","authors":"C. Thitithamrongchai, B. Eua‐arporn","doi":"10.1109/ICPST.2006.321534","DOIUrl":"https://doi.org/10.1109/ICPST.2006.321534","url":null,"abstract":"This paper presents an efficient method for solving economic load dispatch (ELD) problems using a hybrid self- adaptive differential evolution with augmented Lagrange multiplier method (SADE_ALM). Treated as additional control variables, two strategic parameters called the mutation factor (F) and the crossover constant (CR) are dynamically self-adaptive throughout the evolutionary process. Since tuning of the parameters is a tedious task due to complex relationship among parameters, the optimal parameter settings may never be found, and possibly leads to a local optimal solution. An augmented lagrange multiplier method (ALM) is applied to handle equality/inequality constraints. To demonstrate the effectiveness of the proposed algorithm, two ELD problems considering: (1) multiple fuels, and (2) multiple fuels with valve-point effects, are tested and compared with other methods e.g. differential evolution (DE) based methods, modified particle swarm optimization (MPSO), improved genetic algorithm with multiplier updating (IGA_MU) etc. The results show that the proposed SADE_ALM is very effective and provides promising capability for solving the economic load dispatch problem with piecewise quadratic cost function.","PeriodicalId":181574,"journal":{"name":"2006 International Conference on Power System Technology","volume":"63 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128732590","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 : 2006-10-01DOI: 10.1109/ICPST.2006.321928
A. Salimi-beni, M. Fotuhi‐Firuzabad, D. Farrokhzad, S. J. Alemohammad
Electricity demand varies from place to place and from country to country depending on the mix of demand, the climate, and other factors. A typical load curve of a power electricity system through one period of time is normally divided into three parts as base, intermediate and peak-load. While having accurate information for the three parts of a load curve is very important, it is not an easy task to calculate the base, intermediate and peak-load of a particular system. This paper presents a new statistical approach to calculate the three main parts of a system load demand; base, intermediate and peak-load using a cluster analysis which is one of the statistical methods to in data categorizing. The main advantage of the proposed technique is that it can be applied to situations in which LDC or system load factor varies. The applicability of the proposed technique is illustrated by determining the base, intermediate and peak-load for different seasons of Iran power network.
{"title":"A New Approach to Determine Base, Intermediate and Peak-Demand in an Electric Power System","authors":"A. Salimi-beni, M. Fotuhi‐Firuzabad, D. Farrokhzad, S. J. Alemohammad","doi":"10.1109/ICPST.2006.321928","DOIUrl":"https://doi.org/10.1109/ICPST.2006.321928","url":null,"abstract":"Electricity demand varies from place to place and from country to country depending on the mix of demand, the climate, and other factors. A typical load curve of a power electricity system through one period of time is normally divided into three parts as base, intermediate and peak-load. While having accurate information for the three parts of a load curve is very important, it is not an easy task to calculate the base, intermediate and peak-load of a particular system. This paper presents a new statistical approach to calculate the three main parts of a system load demand; base, intermediate and peak-load using a cluster analysis which is one of the statistical methods to in data categorizing. The main advantage of the proposed technique is that it can be applied to situations in which LDC or system load factor varies. The applicability of the proposed technique is illustrated by determining the base, intermediate and peak-load for different seasons of Iran power network.","PeriodicalId":181574,"journal":{"name":"2006 International Conference on Power System Technology","volume":"89 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129013678","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 : 2006-10-01DOI: 10.1109/ICPST.2006.321606
Honghai Tang, Chunwen Li, Yanhong Liu
The Hα robust controller design of AC/DC power system is investigated in this paper. Firstly, a novel fifth-order uncertain non-affine nonlinear model is put forward which describes the dynamics of both DC and AC systems. Then, an Hα controller is constructed by employing the feedback linearization technique and linear Hα theory. It is shown that the stability of the system is enhanced by the proposed firing angle control of the converter. The robust performance is improved as well. Simulation results illustrate the effectiveness of the proposed control strategy.
{"title":"Hα Robust Control of AC/DC Power Systems Based on Non-affine Nonlinear Model","authors":"Honghai Tang, Chunwen Li, Yanhong Liu","doi":"10.1109/ICPST.2006.321606","DOIUrl":"https://doi.org/10.1109/ICPST.2006.321606","url":null,"abstract":"The Hα robust controller design of AC/DC power system is investigated in this paper. Firstly, a novel fifth-order uncertain non-affine nonlinear model is put forward which describes the dynamics of both DC and AC systems. Then, an Hα controller is constructed by employing the feedback linearization technique and linear Hα theory. It is shown that the stability of the system is enhanced by the proposed firing angle control of the converter. The robust performance is improved as well. Simulation results illustrate the effectiveness of the proposed control strategy.","PeriodicalId":181574,"journal":{"name":"2006 International Conference on Power System Technology","volume":"110 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124601933","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 : 2006-10-01DOI: 10.1109/ICPST.2006.321610
K. Naidoo, N. Ijumba, A. Britten
A study of the role played by bird streamers (bird excretements) in transmission line faults under HVDC conditions is described in this paper. The research was initiated due to the lack of knowledge regarding this phenomenon. An insight is given as to what bird streamers faults are, and their role in the breakdown of air-gaps. A model HVDC transmission line tower has been built at the HVDC laboratory at the University of KwaZulu-Natal. The tower was used facilitate in the air-gap breakdown tests. The tests were carried out in order to find the minimum distance required on a transmission tower top for a flashover to occur. The results obtained show that a streamer effectively reduces the air-gap between the tower and the live fitting on a tower. An indication of future work will be given.
{"title":"Bird Streamer Initiated Breakdown Characteristics under HVDC Conditions","authors":"K. Naidoo, N. Ijumba, A. Britten","doi":"10.1109/ICPST.2006.321610","DOIUrl":"https://doi.org/10.1109/ICPST.2006.321610","url":null,"abstract":"A study of the role played by bird streamers (bird excretements) in transmission line faults under HVDC conditions is described in this paper. The research was initiated due to the lack of knowledge regarding this phenomenon. An insight is given as to what bird streamers faults are, and their role in the breakdown of air-gaps. A model HVDC transmission line tower has been built at the HVDC laboratory at the University of KwaZulu-Natal. The tower was used facilitate in the air-gap breakdown tests. The tests were carried out in order to find the minimum distance required on a transmission tower top for a flashover to occur. The results obtained show that a streamer effectively reduces the air-gap between the tower and the live fitting on a tower. An indication of future work will be given.","PeriodicalId":181574,"journal":{"name":"2006 International Conference on Power System Technology","volume":"122 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129124744","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}
The fault current of the faulty feeder is quite low when a single-phase earth fault occurs on a neutral un-effectively grounded grid. The accurate identification of the faulty feeder becomes a difficult task due to many disadvantageous factors. The conventional scheme is implemented with the comparison of the magnitude, polarity or the phase angle among the zero-sequence currents. Therefore, it is hard to be implemented into the feeder protection equipped on the FTU. A novel zero-sequence over-voltage protection scheme based on zero-sequence current compensation is therefore proposed. The fundamental method is based on the measurement of the zero-sequence over-voltage, and the tripping time characteristic adopts the inverse time delay. By virtue of the analysis of distribution of the zero-sequence transient current, a transient RMS value of the zero-sequence current is utilized to form the composite compensation voltage together with zero-sequence voltage. This voltage is utilized to revise the inverse time-delay curve to achieve the selectivity of the protection. The principle is verified with the EMTP simulator.
{"title":"A Novel Adaptive Protective Scheme For the Single-Phase Earth Fault of the Non-Effectively Grounded Power Systems","authors":"Xiangning Lin, Xiaofei Ma, Weng Hanli, Wenjun Lu, Qing Tian","doi":"10.1109/ICPST.2006.321947","DOIUrl":"https://doi.org/10.1109/ICPST.2006.321947","url":null,"abstract":"The fault current of the faulty feeder is quite low when a single-phase earth fault occurs on a neutral un-effectively grounded grid. The accurate identification of the faulty feeder becomes a difficult task due to many disadvantageous factors. The conventional scheme is implemented with the comparison of the magnitude, polarity or the phase angle among the zero-sequence currents. Therefore, it is hard to be implemented into the feeder protection equipped on the FTU. A novel zero-sequence over-voltage protection scheme based on zero-sequence current compensation is therefore proposed. The fundamental method is based on the measurement of the zero-sequence over-voltage, and the tripping time characteristic adopts the inverse time delay. By virtue of the analysis of distribution of the zero-sequence transient current, a transient RMS value of the zero-sequence current is utilized to form the composite compensation voltage together with zero-sequence voltage. This voltage is utilized to revise the inverse time-delay curve to achieve the selectivity of the protection. The principle is verified with the EMTP simulator.","PeriodicalId":181574,"journal":{"name":"2006 International Conference on Power System Technology","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130677791","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 : 2006-10-01DOI: 10.1109/ICPST.2006.321856
Xiao-Xuan Long, Wei Yan, Zhi-G. Lu
This paper presents a new probabilistic algorithm to evaluate the transmission losses. The proposed method accounts for the uncertainty of the network structure and electric loads, operation practices of generating units and voltage/reactive power regulation. Where, the transmission losses are computed by nonlinear power flow method with the system operation states being simulated in detail, and the probabilistic distribution is determined by Monte Carlo simulation method. Because the affects to transmission losses is fully considered by the proposed method, the result is more accurate and more useful. Simulation example is given to testify the validity and efficiency of the proposed method.
{"title":"Monte Carlo Method for Line Losses Evaluation in Transmission Network","authors":"Xiao-Xuan Long, Wei Yan, Zhi-G. Lu","doi":"10.1109/ICPST.2006.321856","DOIUrl":"https://doi.org/10.1109/ICPST.2006.321856","url":null,"abstract":"This paper presents a new probabilistic algorithm to evaluate the transmission losses. The proposed method accounts for the uncertainty of the network structure and electric loads, operation practices of generating units and voltage/reactive power regulation. Where, the transmission losses are computed by nonlinear power flow method with the system operation states being simulated in detail, and the probabilistic distribution is determined by Monte Carlo simulation method. Because the affects to transmission losses is fully considered by the proposed method, the result is more accurate and more useful. Simulation example is given to testify the validity and efficiency of the proposed method.","PeriodicalId":181574,"journal":{"name":"2006 International Conference on Power System Technology","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123236049","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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