Pub Date : 1995-11-21DOI: 10.1109/EMPD.1995.500775
M. Agarwal, F. E. El-Refai, M. Hariharan
Computer simulation of switching transients which occur during starting of high-voltage motors is helpful in determining the voltage stresses which the motor insulation may be subjected to. Also, because of the practical constraints in performing field tests for various conditions, it is preferable to resort to simulating motor circuits rather than using an actual motor itself for switching tests. This paper highlights the simulation of the transient conditions in an induction motor following interruption of the starting current. Studies have been carried out using equivalent circuits which simulate various components of the system, using EMTDC (Electromagnetic Transient Simulation) program, and an IEC model of a standard test circuit valid for carrying out laboratory tests was investigated.
{"title":"Computer studies of high-voltage motor switching transients","authors":"M. Agarwal, F. E. El-Refai, M. Hariharan","doi":"10.1109/EMPD.1995.500775","DOIUrl":"https://doi.org/10.1109/EMPD.1995.500775","url":null,"abstract":"Computer simulation of switching transients which occur during starting of high-voltage motors is helpful in determining the voltage stresses which the motor insulation may be subjected to. Also, because of the practical constraints in performing field tests for various conditions, it is preferable to resort to simulating motor circuits rather than using an actual motor itself for switching tests. This paper highlights the simulation of the transient conditions in an induction motor following interruption of the starting current. Studies have been carried out using equivalent circuits which simulate various components of the system, using EMTDC (Electromagnetic Transient Simulation) program, and an IEC model of a standard test circuit valid for carrying out laboratory tests was investigated.","PeriodicalId":447674,"journal":{"name":"Proceedings 1995 International Conference on Energy Management and Power Delivery EMPD '95","volume":"30 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114099963","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 : 1995-11-21DOI: 10.1109/EMPD.1995.500815
Tsai-Hsiang Chen, Shyi-Wen Wang
This paper introduces the applications of three novel distribution feeder models for accelerating the calculations of voltage drops and power losses in a distribution system. These models are formulated using lumped loads to represent discretely distributed tapped-off loads along a feeder. They are used to represent the features of reversible power flow. These models are important for a modern power distribution system, especially for those with the distribution management system in which the direction of the power flows in the switched feeders may reverse while performing the system reconfiguration or restoration function. These bi-directional feeder models are applied to an actual feeder of Taiwan Power Company. The simulation results show the correctness of these novel models. Also, the results show the possibility that many complex feeders, laterals and feeder segments can be represented by their simple equivalent models in the study of feeder voltage profiles and losses with negligible error, even if the direction of the power flows in the given feeders or feeder segments are changed.
{"title":"Applications of simplified bi-directional feeder models for accelerating the voltage-drop and power-loss calculations","authors":"Tsai-Hsiang Chen, Shyi-Wen Wang","doi":"10.1109/EMPD.1995.500815","DOIUrl":"https://doi.org/10.1109/EMPD.1995.500815","url":null,"abstract":"This paper introduces the applications of three novel distribution feeder models for accelerating the calculations of voltage drops and power losses in a distribution system. These models are formulated using lumped loads to represent discretely distributed tapped-off loads along a feeder. They are used to represent the features of reversible power flow. These models are important for a modern power distribution system, especially for those with the distribution management system in which the direction of the power flows in the switched feeders may reverse while performing the system reconfiguration or restoration function. These bi-directional feeder models are applied to an actual feeder of Taiwan Power Company. The simulation results show the correctness of these novel models. Also, the results show the possibility that many complex feeders, laterals and feeder segments can be represented by their simple equivalent models in the study of feeder voltage profiles and losses with negligible error, even if the direction of the power flows in the given feeders or feeder segments are changed.","PeriodicalId":447674,"journal":{"name":"Proceedings 1995 International Conference on Energy Management and Power Delivery EMPD '95","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121747051","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 : 1995-11-21DOI: 10.1109/EMPD.1995.500795
P. Balasubramanyam, A. Murty, B. Sarkar
Analysis and damping of torsional oscillations through thyristor controlled reactors (TCR) is presented in this paper. The reactive power control is achieved through TCR at the machine terminals. Generator speed signal is used as the auxiliary signal and the terminal voltage feedback signal as the main control signal for the TCR. The following control strategies for auxiliary control of TCRs have been analysed: (1) analysis of basic system without damping controls; (2) proportional control; (3) proportional control with filter; (4) proportional derivative control filter; and (5) proportional plus integral plus derivative control with filter. The main objective of this paper is to discuss the performance of different control strategies for damping torsional oscillations when a generator is connected to an infinite bus via a double circuit 400 kV transmission line, in which one circuit is series compensated. This configuration is similar to IEEE benchmark two model.
{"title":"Analysis of supplementary controls in damping subsynchronous oscillations","authors":"P. Balasubramanyam, A. Murty, B. Sarkar","doi":"10.1109/EMPD.1995.500795","DOIUrl":"https://doi.org/10.1109/EMPD.1995.500795","url":null,"abstract":"Analysis and damping of torsional oscillations through thyristor controlled reactors (TCR) is presented in this paper. The reactive power control is achieved through TCR at the machine terminals. Generator speed signal is used as the auxiliary signal and the terminal voltage feedback signal as the main control signal for the TCR. The following control strategies for auxiliary control of TCRs have been analysed: (1) analysis of basic system without damping controls; (2) proportional control; (3) proportional control with filter; (4) proportional derivative control filter; and (5) proportional plus integral plus derivative control with filter. The main objective of this paper is to discuss the performance of different control strategies for damping torsional oscillations when a generator is connected to an infinite bus via a double circuit 400 kV transmission line, in which one circuit is series compensated. This configuration is similar to IEEE benchmark two model.","PeriodicalId":447674,"journal":{"name":"Proceedings 1995 International Conference on Energy Management and Power Delivery EMPD '95","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124808321","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 : 1995-11-21DOI: 10.1109/EMPD.1995.500774
T. S. Sidhu, M. S. Sachdev
This paper describes the laboratory used for teaching and conducting research in the Department of Electrical Engineering at the University of Saskatchewan, Canada, in the area of computer-based power system protection. The laboratory facilities are used for conducting research and teaching protection related courses. The use of the laboratory is illustrated by describing the implementation of two recent research projects for which laboratory facilities have been used.
{"title":"Laboratory setup for teaching and research in computer-based power system protection","authors":"T. S. Sidhu, M. S. Sachdev","doi":"10.1109/EMPD.1995.500774","DOIUrl":"https://doi.org/10.1109/EMPD.1995.500774","url":null,"abstract":"This paper describes the laboratory used for teaching and conducting research in the Department of Electrical Engineering at the University of Saskatchewan, Canada, in the area of computer-based power system protection. The laboratory facilities are used for conducting research and teaching protection related courses. The use of the laboratory is illustrated by describing the implementation of two recent research projects for which laboratory facilities have been used.","PeriodicalId":447674,"journal":{"name":"Proceedings 1995 International Conference on Energy Management and Power Delivery EMPD '95","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128922664","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 : 1995-11-21DOI: 10.1109/EMPD.1995.500706
A. Ebert, M. Eppel, S. Genthe, H. Schwarzjirg, J. Stark, W. Werner
In a large SCADA/EMS-system an expert system for fault diagnosis and for system restoration is integrated. The system restoration covered by the expert system gives assistance to the operator in any kind of blackout by presenting restoration plans. In case any number of busbars is outaged the system automatically determines the affected network areas and thereby the magnitude of the whole blackout. The restoration of the network is done in phases depending on the kind of blackout and is based on a global utility-strategy-plan. Within this scheme the detailed restoration plan is determined dynamically based on the actual situation and some predefinitions such as load priorities and power plants to be reenergized with priority. The described system covers all cases of blackouts by evaluating a plan based on the individual case. The expert system is a hybrid system using an optimal power flow, too, and is fully integrated in the SCADA/EMS system. The plans of each phase are presented via the common MMI to the operator and supervised due to execution. The system distinguishes between operator wanted deviations and unwanted deviations during execution. Thus the operator at any time can continue as he likes.
{"title":"System restoration of a transmission network","authors":"A. Ebert, M. Eppel, S. Genthe, H. Schwarzjirg, J. Stark, W. Werner","doi":"10.1109/EMPD.1995.500706","DOIUrl":"https://doi.org/10.1109/EMPD.1995.500706","url":null,"abstract":"In a large SCADA/EMS-system an expert system for fault diagnosis and for system restoration is integrated. The system restoration covered by the expert system gives assistance to the operator in any kind of blackout by presenting restoration plans. In case any number of busbars is outaged the system automatically determines the affected network areas and thereby the magnitude of the whole blackout. The restoration of the network is done in phases depending on the kind of blackout and is based on a global utility-strategy-plan. Within this scheme the detailed restoration plan is determined dynamically based on the actual situation and some predefinitions such as load priorities and power plants to be reenergized with priority. The described system covers all cases of blackouts by evaluating a plan based on the individual case. The expert system is a hybrid system using an optimal power flow, too, and is fully integrated in the SCADA/EMS system. The plans of each phase are presented via the common MMI to the operator and supervised due to execution. The system distinguishes between operator wanted deviations and unwanted deviations during execution. Thus the operator at any time can continue as he likes.","PeriodicalId":447674,"journal":{"name":"Proceedings 1995 International Conference on Energy Management and Power Delivery EMPD '95","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121098946","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 : 1995-11-21DOI: 10.1109/EMPD.1995.500767
Z. Chen, Akhtar Kalam, A. Zayegh
This paper describes an intelligent embedded microprocessor based system for fault classification in power system protection system using advanced 32-bit microprocessor technology. The paper demonstrates the development of a protective relay to provide overcurrent protection schemes for fault detection. It also describes a method for power fault classification in a three-phase system based on the use of neural network technology. The proposed design is implemented and tested on a single line three phase power system in a power laboratory. Both the hardware and software development are described in detail.
{"title":"Advanced microprocessor based power protection system using artificial neural network techniques","authors":"Z. Chen, Akhtar Kalam, A. Zayegh","doi":"10.1109/EMPD.1995.500767","DOIUrl":"https://doi.org/10.1109/EMPD.1995.500767","url":null,"abstract":"This paper describes an intelligent embedded microprocessor based system for fault classification in power system protection system using advanced 32-bit microprocessor technology. The paper demonstrates the development of a protective relay to provide overcurrent protection schemes for fault detection. It also describes a method for power fault classification in a three-phase system based on the use of neural network technology. The proposed design is implemented and tested on a single line three phase power system in a power laboratory. Both the hardware and software development are described in detail.","PeriodicalId":447674,"journal":{"name":"Proceedings 1995 International Conference on Energy Management and Power Delivery EMPD '95","volume":"175 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124312742","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 : 1995-11-21DOI: 10.1109/EMPD.1995.500783
K. Ravi, C. Keshava, M. Naidu
Higher rate of failure of insulators occur in HVDC systems especially in polluted zones. The main reasons for this are surface erosion, ion migration and voltage distribution. Voltage distribution under clean conditions becomes one of the main causes for failure. Experiments have been carried out for the determination of the voltage distribution under varying ambient in which the relative humidity values varied between 19 to 90%. Puncturing and shattering of insulators are the causes of failures that occur in DC lines especially in polluted zones. Various causes of failure have been put forth when the pin of the insulator is positive. However, for negative voltage applied to the pin of the insulator the reasons have not been found yet. Detailed studies have been analysed. The paper presents the details of the study.
{"title":"Study of mechanisms leading to failure of insulators under pollution conditions with DC voltages","authors":"K. Ravi, C. Keshava, M. Naidu","doi":"10.1109/EMPD.1995.500783","DOIUrl":"https://doi.org/10.1109/EMPD.1995.500783","url":null,"abstract":"Higher rate of failure of insulators occur in HVDC systems especially in polluted zones. The main reasons for this are surface erosion, ion migration and voltage distribution. Voltage distribution under clean conditions becomes one of the main causes for failure. Experiments have been carried out for the determination of the voltage distribution under varying ambient in which the relative humidity values varied between 19 to 90%. Puncturing and shattering of insulators are the causes of failures that occur in DC lines especially in polluted zones. Various causes of failure have been put forth when the pin of the insulator is positive. However, for negative voltage applied to the pin of the insulator the reasons have not been found yet. Detailed studies have been analysed. The paper presents the details of the study.","PeriodicalId":447674,"journal":{"name":"Proceedings 1995 International Conference on Energy Management and Power Delivery EMPD '95","volume":"225 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124476943","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 : 1995-11-21DOI: 10.1109/EMPD.1995.500816
T. Rahman, G. Jasmon
Voltage collapse may occur in a power system due to loss in voltage stability in the system. Therefore voltage stability analysis is important in order to identify critical buses in a power system, i.e. buses which are closed to their voltage stability limits and thus enable certain measures to be taken by the control engineer in order to avoid any incidence of voltage collapse. This paper presents a new technique to determine the static voltage stability of load buses in a power system for a certain operating condition and hence identifies load buses which are close to voltage collapse. A voltage stability index with respect to a load bus is formulated from the voltage equation derived from a two bus network and it is computed using a Thevenin equivalent circuit of the power system referred to a load bus. This index indicates how far the load buses are from their voltage stability limits and hence identifies the critical buses. The performance of this index is tested using a 9 bus radial network and the 24 bus IEEE Reliability Test System for its validity. A comparison is also made between this index and the impedance ratio used by Sterling et al. as the voltage collapse indicator. This paper also presents a new loadflow technique to compute the power flow solution for a radial network which is found to be more superior than the Second Order Newton Raphson and Distflow since it takes less iterations to give a loadflow solution.
{"title":"A new technique for voltage stability analysis in a power system and improved loadflow algorithm for distribution network","authors":"T. Rahman, G. Jasmon","doi":"10.1109/EMPD.1995.500816","DOIUrl":"https://doi.org/10.1109/EMPD.1995.500816","url":null,"abstract":"Voltage collapse may occur in a power system due to loss in voltage stability in the system. Therefore voltage stability analysis is important in order to identify critical buses in a power system, i.e. buses which are closed to their voltage stability limits and thus enable certain measures to be taken by the control engineer in order to avoid any incidence of voltage collapse. This paper presents a new technique to determine the static voltage stability of load buses in a power system for a certain operating condition and hence identifies load buses which are close to voltage collapse. A voltage stability index with respect to a load bus is formulated from the voltage equation derived from a two bus network and it is computed using a Thevenin equivalent circuit of the power system referred to a load bus. This index indicates how far the load buses are from their voltage stability limits and hence identifies the critical buses. The performance of this index is tested using a 9 bus radial network and the 24 bus IEEE Reliability Test System for its validity. A comparison is also made between this index and the impedance ratio used by Sterling et al. as the voltage collapse indicator. This paper also presents a new loadflow technique to compute the power flow solution for a radial network which is found to be more superior than the Second Order Newton Raphson and Distflow since it takes less iterations to give a loadflow solution.","PeriodicalId":447674,"journal":{"name":"Proceedings 1995 International Conference on Energy Management and Power Delivery EMPD '95","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121211200","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 : 1995-11-21DOI: 10.1109/EMPD.1995.500768
M. S. Sachdev, T. S. Sidhu, B. K. Talukdar
A general purpose network topology detection technique suitable for use in adaptive relaying applications is presented in this paper. Three test systems were used to check the performance of the proposed technique. Results obtained from the tests are included. The proposed technique was implemented in the laboratory as a part of the implementation of the adaptive protection scheme. The execution times of the topology detection software were monitored and were found to be acceptable.
{"title":"Topology detection for adaptive protection of distribution networks","authors":"M. S. Sachdev, T. S. Sidhu, B. K. Talukdar","doi":"10.1109/EMPD.1995.500768","DOIUrl":"https://doi.org/10.1109/EMPD.1995.500768","url":null,"abstract":"A general purpose network topology detection technique suitable for use in adaptive relaying applications is presented in this paper. Three test systems were used to check the performance of the proposed technique. Results obtained from the tests are included. The proposed technique was implemented in the laboratory as a part of the implementation of the adaptive protection scheme. The execution times of the topology detection software were monitored and were found to be acceptable.","PeriodicalId":447674,"journal":{"name":"Proceedings 1995 International Conference on Energy Management and Power Delivery EMPD '95","volume":"150 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115598825","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 : 1995-11-21DOI: 10.1109/EMPD.1995.500691
M. Lehtonen, B. Lemstrom
This paper gives a comparative study of various methods for assessing the customers' outage costs. The methods considered are the willingness to pay in order to avoid an outage, the willingness to accept compensation for having had an outage, the customer survey where the costs are estimated directly by the customers themselves and an econometric model based on price elasticity. In the case of industrial customers, also the correlation between the outage costs and the value added by the production is examined. The use of different methods is illustrated by the main results of a large Nordic study, carried out in 1992 and 1993.
{"title":"Comparison of the methods for assessing the customers' outage costs","authors":"M. Lehtonen, B. Lemstrom","doi":"10.1109/EMPD.1995.500691","DOIUrl":"https://doi.org/10.1109/EMPD.1995.500691","url":null,"abstract":"This paper gives a comparative study of various methods for assessing the customers' outage costs. The methods considered are the willingness to pay in order to avoid an outage, the willingness to accept compensation for having had an outage, the customer survey where the costs are estimated directly by the customers themselves and an econometric model based on price elasticity. In the case of industrial customers, also the correlation between the outage costs and the value added by the production is examined. The use of different methods is illustrated by the main results of a large Nordic study, carried out in 1992 and 1993.","PeriodicalId":447674,"journal":{"name":"Proceedings 1995 International Conference on Energy Management and Power Delivery EMPD '95","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115352499","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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