The purpose of this paper is the investigation of the harmonic distortion introduced by the compact fluorescent lamps to the distribution systems. The results of some measurements on compact fluorescent lamps (CFL) and on self-ballasted fluorescent lamps (SBL) of various wattages are presented. Some of the most important electrical characteristics (voltage, current and power factor) were measured by a data acquisition system. The harmonic spectrum and the total harmonic distortion (THD) of the lamps were calculated using Fourier analysis of the recorded current waveforms. The measurements were performed with supply voltage other than the nominal one in order to determine the dependence of the THD variation upon the mains supply voltage. From these measurements, conclusions concerning the problem of harmonics are drawn.
{"title":"Harmonic distortion in electric power systems introduced by compact fluorescent lamps","authors":"I. Gonos, M. Kostic, F.V. Topalis","doi":"10.1109/PTC.1999.826727","DOIUrl":"https://doi.org/10.1109/PTC.1999.826727","url":null,"abstract":"The purpose of this paper is the investigation of the harmonic distortion introduced by the compact fluorescent lamps to the distribution systems. The results of some measurements on compact fluorescent lamps (CFL) and on self-ballasted fluorescent lamps (SBL) of various wattages are presented. Some of the most important electrical characteristics (voltage, current and power factor) were measured by a data acquisition system. The harmonic spectrum and the total harmonic distortion (THD) of the lamps were calculated using Fourier analysis of the recorded current waveforms. The measurements were performed with supply voltage other than the nominal one in order to determine the dependence of the THD variation upon the mains supply voltage. From these measurements, conclusions concerning the problem of harmonics are drawn.","PeriodicalId":101688,"journal":{"name":"PowerTech Budapest 99. Abstract Records. (Cat. No.99EX376)","volume":"73 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116625791","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 paper presents a controller for AC motor drives with frequency converters. It controls output frequency of the converter and in such a way-rotation speed of the motor according to the sensor signals to keep the given value of some parameter of the system, e.g. water pressure in water pump outlet, constant. The suggested controller is based on comparators and an operation amplifier. It can be used for rotation speed control of pumps and fans in heating, ventilating and air conditioning or in flow applications. The controller is simple, cheap and is user friendly.
{"title":"Rotation speed controller for AC motor drives with frequency converters","authors":"A. Baskya, V. Gobia","doi":"10.1109/PTC.1999.826526","DOIUrl":"https://doi.org/10.1109/PTC.1999.826526","url":null,"abstract":"The paper presents a controller for AC motor drives with frequency converters. It controls output frequency of the converter and in such a way-rotation speed of the motor according to the sensor signals to keep the given value of some parameter of the system, e.g. water pressure in water pump outlet, constant. The suggested controller is based on comparators and an operation amplifier. It can be used for rotation speed control of pumps and fans in heating, ventilating and air conditioning or in flow applications. The controller is simple, cheap and is user friendly.","PeriodicalId":101688,"journal":{"name":"PowerTech Budapest 99. Abstract Records. (Cat. No.99EX376)","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115268715","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}
To keep the high availability of long EHV transmission lines at reduced phase-to-phase and phase-to-ground distances requires improving the successfulness of automatic reclosing. The authors propose a scheme offering a simple and efficient protection to limit the re-energization overvoltages at a low level and helping the place of the fault to recover.
{"title":"Use of neutral reactors for improving the successfulness of three phase reclosing","authors":"G. Bán, L. Prikler, A. Said","doi":"10.1109/PTC.1999.826573","DOIUrl":"https://doi.org/10.1109/PTC.1999.826573","url":null,"abstract":"To keep the high availability of long EHV transmission lines at reduced phase-to-phase and phase-to-ground distances requires improving the successfulness of automatic reclosing. The authors propose a scheme offering a simple and efficient protection to limit the re-energization overvoltages at a low level and helping the place of the fault to recover.","PeriodicalId":101688,"journal":{"name":"PowerTech Budapest 99. Abstract Records. (Cat. No.99EX376)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116709587","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 paper presents a new technique for the economic dispatch of isolated power systems with a high penetration of renewable forms of energy. It also describes a software module based on this technique integrated on a real-time control system.
{"title":"Economic dispatch in isolated networks with renewables using evolutionary programming","authors":"L. M. Proença, J. L. Pinto, M. Matos","doi":"10.1109/PTC.1999.826471","DOIUrl":"https://doi.org/10.1109/PTC.1999.826471","url":null,"abstract":"The paper presents a new technique for the economic dispatch of isolated power systems with a high penetration of renewable forms of energy. It also describes a software module based on this technique integrated on a real-time control system.","PeriodicalId":101688,"journal":{"name":"PowerTech Budapest 99. Abstract Records. (Cat. No.99EX376)","volume":"18 4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116694153","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 ageing of oil immersed cellulose insulation material mainly depends on its thermal load. Up to now cellulose insulation is used in most of the power transformers. In order to give special attention to the thermal behavior of oil immersed power transformers, a monitoring system was developed. The system measures the load, typical temperatures of the transformer and its cooling units, the tap changer position and the state of fans and pumps of all cooling units. In addition the output signal of a gas-in-oil sensor is evaluated. The hardware setup and the thermal monitoring algorithms used in the system are described. In order to determine the winding temperature distribution with improved accuracy a thermal model has been designed and integrated in the monitoring system.
{"title":"Thermal monitoring of large power transformers","authors":"M. Schafer, K. Feser","doi":"10.1109/PTC.1999.826529","DOIUrl":"https://doi.org/10.1109/PTC.1999.826529","url":null,"abstract":"The ageing of oil immersed cellulose insulation material mainly depends on its thermal load. Up to now cellulose insulation is used in most of the power transformers. In order to give special attention to the thermal behavior of oil immersed power transformers, a monitoring system was developed. The system measures the load, typical temperatures of the transformer and its cooling units, the tap changer position and the state of fans and pumps of all cooling units. In addition the output signal of a gas-in-oil sensor is evaluated. The hardware setup and the thermal monitoring algorithms used in the system are described. In order to determine the winding temperature distribution with improved accuracy a thermal model has been designed and integrated in the monitoring system.","PeriodicalId":101688,"journal":{"name":"PowerTech Budapest 99. Abstract Records. (Cat. No.99EX376)","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114826717","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}
M. S. Rodrigues, J. Souza, M. Do Coutto Filho, M. Schilling
Summary form only given. This paper presents a method for power systems automatic contingency selection and static security evaluation. It is possible to identify potentially harmful contingencies in a very short computational time, being the risk of false alarms and contingency misses. The method is tested for many different operating conditions and simulated with the IEEE 24 bus test system. Classification rates for contingency selection and static security evaluation are also provided.
{"title":"Automatic contingency selection based on a pattern analysis approach","authors":"M. S. Rodrigues, J. Souza, M. Do Coutto Filho, M. Schilling","doi":"10.1109/PTC.1999.826611","DOIUrl":"https://doi.org/10.1109/PTC.1999.826611","url":null,"abstract":"Summary form only given. This paper presents a method for power systems automatic contingency selection and static security evaluation. It is possible to identify potentially harmful contingencies in a very short computational time, being the risk of false alarms and contingency misses. The method is tested for many different operating conditions and simulated with the IEEE 24 bus test system. Classification rates for contingency selection and static security evaluation are also provided.","PeriodicalId":101688,"journal":{"name":"PowerTech Budapest 99. Abstract Records. (Cat. No.99EX376)","volume":"67 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121408442","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 paper describes a methodology for the reduction of standing phase angle (SPA) difference between two buses during restoration operations of a power system. These angles may occur across a tie line, between two systems or between two connected subsystems within a system which may causes significant delay in power system restoration. They must be within SPA limits before an attempt is made to close breakers to firm up the bulk power transmission system. To arrive at the desired SPA difference between two buses, the modified contribution at generation/load buses have been evaluated based on sensitivity factors. This methodology acts as a direct help to reduce excessive SPA difference between two buses to an acceptable limit, which otherwise requires regulation of various generation levels on a trial and error basis.
{"title":"New approach to standing phase angle reduction for power system restoration","authors":"K. Ketabi, A. Ranjbar","doi":"10.1109/PTC.1999.826509","DOIUrl":"https://doi.org/10.1109/PTC.1999.826509","url":null,"abstract":"The paper describes a methodology for the reduction of standing phase angle (SPA) difference between two buses during restoration operations of a power system. These angles may occur across a tie line, between two systems or between two connected subsystems within a system which may causes significant delay in power system restoration. They must be within SPA limits before an attempt is made to close breakers to firm up the bulk power transmission system. To arrive at the desired SPA difference between two buses, the modified contribution at generation/load buses have been evaluated based on sensitivity factors. This methodology acts as a direct help to reduce excessive SPA difference between two buses to an acceptable limit, which otherwise requires regulation of various generation levels on a trial and error basis.","PeriodicalId":101688,"journal":{"name":"PowerTech Budapest 99. Abstract Records. (Cat. No.99EX376)","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121728701","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}
This paper presents efficient shielding ways for minimizing the electric field at ground surfaces resulting from the three-phase double circuit high voltage transmission lines existing in Kuwait, and in turn reducing the amount of land required as rights-of-ways. The charge simulation method (CSM) is used for field computations. Shielding is offered by two different methods. The first method is by using a vertical grid and the other uses a horizontal grid consisting of a number of grounded wires. The effect of the grid design parameters is extensively studied. The two shielding methods are also applied to reduce the right-of-way widths of two 3-phase double circuits transmission lines running in parallel in Kuwait. Good results have been obtained and shielding grid design parameters have been recommended for those systems.
{"title":"Shielding design methods for Kuwait high voltage double circuits electrical networks","authors":"H. M. Ismail","doi":"10.1109/PTC.1999.826630","DOIUrl":"https://doi.org/10.1109/PTC.1999.826630","url":null,"abstract":"This paper presents efficient shielding ways for minimizing the electric field at ground surfaces resulting from the three-phase double circuit high voltage transmission lines existing in Kuwait, and in turn reducing the amount of land required as rights-of-ways. The charge simulation method (CSM) is used for field computations. Shielding is offered by two different methods. The first method is by using a vertical grid and the other uses a horizontal grid consisting of a number of grounded wires. The effect of the grid design parameters is extensively studied. The two shielding methods are also applied to reduce the right-of-way widths of two 3-phase double circuits transmission lines running in parallel in Kuwait. Good results have been obtained and shielding grid design parameters have been recommended for those systems.","PeriodicalId":101688,"journal":{"name":"PowerTech Budapest 99. Abstract Records. (Cat. No.99EX376)","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123624644","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}
Competitive electricity market often requires the separation of transmission and generating services; therefore, the transmission system operator does not have an impact on short and long term generation patterns. At the same time, the transmission operator needs to accommodate various transactions and generation patterns. In the desire to accommodate market-based transactions, the transmission operator is very much interested in quantifying the various stability margins (voltage, dynamic, etc.) and in determining the level of robustness of the transmission system. In the case of voltage stability, the index of robustness used is the difference from the current operating condition to an infeasible point. Particularly relevant is the amount of additional reactive load that can be accommodated before the system experiences a voltage collapse. In this paper, we present a development of OPFs based on primal-dual nonlinear interior-point method, which can handle maximum loadability constraint under contingency state. The developed OFF can solve the optimal operating point while keeping enough loadability margin under contingency state. In order to demonstrate the advantage of the proposed methods, the OPFs are applied to several test systems under various operating conditions.
{"title":"Application of optimal power flow for voltage stability problem","authors":"J. Kubokawa, H. Sasaki, S. Ahmed, G. Strbac","doi":"10.1109/PTC.1999.826466","DOIUrl":"https://doi.org/10.1109/PTC.1999.826466","url":null,"abstract":"Competitive electricity market often requires the separation of transmission and generating services; therefore, the transmission system operator does not have an impact on short and long term generation patterns. At the same time, the transmission operator needs to accommodate various transactions and generation patterns. In the desire to accommodate market-based transactions, the transmission operator is very much interested in quantifying the various stability margins (voltage, dynamic, etc.) and in determining the level of robustness of the transmission system. In the case of voltage stability, the index of robustness used is the difference from the current operating condition to an infeasible point. Particularly relevant is the amount of additional reactive load that can be accommodated before the system experiences a voltage collapse. In this paper, we present a development of OPFs based on primal-dual nonlinear interior-point method, which can handle maximum loadability constraint under contingency state. The developed OFF can solve the optimal operating point while keeping enough loadability margin under contingency state. In order to demonstrate the advantage of the proposed methods, the OPFs are applied to several test systems under various operating conditions.","PeriodicalId":101688,"journal":{"name":"PowerTech Budapest 99. Abstract Records. (Cat. No.99EX376)","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125308543","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}
In this paper, we propose a robust design method for excitation control of a power system for the typical case where different machines are connected to the common bus terminal. In the design method, we do not need to equalize the generators. We design one controller for each specified generator independently without knowing the parameters of other generators. Thus all the problems caused by the equalization are automatically eliminated. Using only local variables at the transformer ends, we can design the controllers for each generator separately despite the nonlinearities and interconnections among different generators. A two-generator example test system is presented to illustrate the effectiveness of the proposed excitation control system. For comparison, simulation between the proposed approach and the equalization approach, and the proposed approach and PSS are given. The results show that the equalization approach is not accurate in analysis of power system transient stability, but the proposed controller can effectively enhance the system transient stability and improve the system damping.
{"title":"Robust nonlinear control for a power system with multiple machines connected to the common bus terminal","authors":"L. Zhang, Y. Wang, G. Guo, D. J. Hill","doi":"10.1109/PTC.1999.826668","DOIUrl":"https://doi.org/10.1109/PTC.1999.826668","url":null,"abstract":"In this paper, we propose a robust design method for excitation control of a power system for the typical case where different machines are connected to the common bus terminal. In the design method, we do not need to equalize the generators. We design one controller for each specified generator independently without knowing the parameters of other generators. Thus all the problems caused by the equalization are automatically eliminated. Using only local variables at the transformer ends, we can design the controllers for each generator separately despite the nonlinearities and interconnections among different generators. A two-generator example test system is presented to illustrate the effectiveness of the proposed excitation control system. For comparison, simulation between the proposed approach and the equalization approach, and the proposed approach and PSS are given. The results show that the equalization approach is not accurate in analysis of power system transient stability, but the proposed controller can effectively enhance the system transient stability and improve the system damping.","PeriodicalId":101688,"journal":{"name":"PowerTech Budapest 99. Abstract Records. (Cat. No.99EX376)","volume":"72 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122603385","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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