Pub Date : 1995-11-21DOI: 10.1109/EMPD.1995.500771
S. Tso, S. P. Cheung
Recent developments in transient stability margin (TSM) prediction using the energy-based direct method have included excitation controllers, power system stabilizers (PSSs) and/or static VAr compensators (SVCs). These devices can be represented in their detailed dynamic models to desired degrees of complexity while the proposed "extended" equal-area criterion can still be effectively applied. This paper describes further development of this technique to incorporate an HVDC transmission into the test network for TSM prediction. The method is examined with a practical 17-machine power network representing the South China/Hong Kong system. An SVC control scheme is also installed in a weak bus of the test network for transient stability improvement. The results obtained show that there is no sacrifice in accuracy, speed or reliability of the TSM method with SVC and HVDC realistically incorporated into the study.
{"title":"Fast prediction of transient stability margin in systems with SVC control and HVDC link","authors":"S. Tso, S. P. Cheung","doi":"10.1109/EMPD.1995.500771","DOIUrl":"https://doi.org/10.1109/EMPD.1995.500771","url":null,"abstract":"Recent developments in transient stability margin (TSM) prediction using the energy-based direct method have included excitation controllers, power system stabilizers (PSSs) and/or static VAr compensators (SVCs). These devices can be represented in their detailed dynamic models to desired degrees of complexity while the proposed \"extended\" equal-area criterion can still be effectively applied. This paper describes further development of this technique to incorporate an HVDC transmission into the test network for TSM prediction. The method is examined with a practical 17-machine power network representing the South China/Hong Kong system. An SVC control scheme is also installed in a weak bus of the test network for transient stability improvement. The results obtained show that there is no sacrifice in accuracy, speed or reliability of the TSM method with SVC and HVDC realistically incorporated into the study.","PeriodicalId":447674,"journal":{"name":"Proceedings 1995 International Conference on Energy Management and Power Delivery EMPD '95","volume":"9 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":"130738810","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.1995.500731
A. Nikander, E. Lakervi, J. Suontausta
The treatment of the neutral of a medium voltage power system has a major influence on the system behaviour. Earth faults in isolated and compensated power systems are simulated. The results contribute to various developments for improved power system protection. Conditions in radially operated rural 20 kV overhead distribution networks are considered.
{"title":"Applications of transient phenomena during earth-faults in electricity distribution networks","authors":"A. Nikander, E. Lakervi, J. Suontausta","doi":"10.1109/EMPD.1995.500731","DOIUrl":"https://doi.org/10.1109/EMPD.1995.500731","url":null,"abstract":"The treatment of the neutral of a medium voltage power system has a major influence on the system behaviour. Earth faults in isolated and compensated power systems are simulated. The results contribute to various developments for improved power system protection. Conditions in radially operated rural 20 kV overhead distribution networks are considered.","PeriodicalId":447674,"journal":{"name":"Proceedings 1995 International Conference on Energy Management and Power Delivery EMPD '95","volume":"420 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":"129383133","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.1995.500800
Sei Chan, A. Omar
This paper describes the application of a new simple voltage-boosting feature to a split-supply SR (switched-reluctance) motor inverter. As its name implies, the SR motor always operates in switching mode and has distinct motoring and generating rotor angular regions. The effectiveness of the energy conversion process of the SR motor depends basically on the ability of its inverter to inject adequate current during the positive-torque angular region and to reduce the current to a negligible value during the negative-torque angular region. The modified inverter effectively generates boost voltages for accelerating current build-up and decay and hence enhances the performance of SR motor drives. Benefits of the added boosting include: higher average current; better energy recovery during commutation; and a wider feasible speed range. This paper assesses the implications of the boost feature on inverter cost and performance. A time-stepping simulation procedure which includes the modelling of current overlapping between phases is presented together with simulation results.
{"title":"A modified split-supply switched-reluctance drive inverter","authors":"Sei Chan, A. Omar","doi":"10.1109/EMPD.1995.500800","DOIUrl":"https://doi.org/10.1109/EMPD.1995.500800","url":null,"abstract":"This paper describes the application of a new simple voltage-boosting feature to a split-supply SR (switched-reluctance) motor inverter. As its name implies, the SR motor always operates in switching mode and has distinct motoring and generating rotor angular regions. The effectiveness of the energy conversion process of the SR motor depends basically on the ability of its inverter to inject adequate current during the positive-torque angular region and to reduce the current to a negligible value during the negative-torque angular region. The modified inverter effectively generates boost voltages for accelerating current build-up and decay and hence enhances the performance of SR motor drives. Benefits of the added boosting include: higher average current; better energy recovery during commutation; and a wider feasible speed range. This paper assesses the implications of the boost feature on inverter cost and performance. A time-stepping simulation procedure which includes the modelling of current overlapping between phases is presented together with simulation results.","PeriodicalId":447674,"journal":{"name":"Proceedings 1995 International Conference on Energy Management and Power Delivery EMPD '95","volume":"23 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":"131879999","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.1995.500710
H. H. Wong, J. C. Flores, Ying Fang, R.P. Baldevia
This paper describes the development of a new automatic underfrequency load shedding scheme on the Guam Power Authority's (GPA) system using a transient stability simulation program. The new scheme strives to minimize the amount of load shed by selecting frequency settings based on the severity of generation or load unbalance and the availability of spinning reserves. The fast speed of frequency decay due to loss of generation is shown to be particularly pronounced in an island system, requiring more careful design of any load shedding scheme than large interconnected systems. The use of a well-prepared transient stability study model allows the simulation of specific contingencies and the fine-tuning of load shedding strategies for optimality. The trade-off between equipment protection, customer service availability, and practical operating issues, such as, synchronization of generators to the grid, are discussed.
{"title":"Guam Power Authority automatic underfrequency load shedding study","authors":"H. H. Wong, J. C. Flores, Ying Fang, R.P. Baldevia","doi":"10.1109/EMPD.1995.500710","DOIUrl":"https://doi.org/10.1109/EMPD.1995.500710","url":null,"abstract":"This paper describes the development of a new automatic underfrequency load shedding scheme on the Guam Power Authority's (GPA) system using a transient stability simulation program. The new scheme strives to minimize the amount of load shed by selecting frequency settings based on the severity of generation or load unbalance and the availability of spinning reserves. The fast speed of frequency decay due to loss of generation is shown to be particularly pronounced in an island system, requiring more careful design of any load shedding scheme than large interconnected systems. The use of a well-prepared transient stability study model allows the simulation of specific contingencies and the fine-tuning of load shedding strategies for optimality. The trade-off between equipment protection, customer service availability, and practical operating issues, such as, synchronization of generators to the grid, are discussed.","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":"129786292","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.1995.500734
F. Dahlfors, J. Pilling
The traditional energy management system (EMS) has, until recently, remained isolated from other electric utility information systems, putting limits on its potential to the power company. Today, information technology (IT) can offer efficient and cost-justified solutions for the integration of these resources, and the value of IT is being increasingly recognized by many power companies. The current wave of privatisation, deregulation and market orientation of the electric energy market in many parts of the world has created new challenges. Power companies are now cast in the role of energy service companies instead of energy suppliers. The increasing competition and the requirements for improved overall economy and quality of services is accelerating the demand for more accurate and up-to-date information. Information has become a strategic resource. To exploit its full potential for all users, the keyword is integration. Technical, business and administrative applications need to be viewed in a corporate wide perspective. A revised IT strategy has become a tool for positioning the power company in a competitive market.
{"title":"Integrated information systems in a privatized and deregulated electricity market","authors":"F. Dahlfors, J. Pilling","doi":"10.1109/EMPD.1995.500734","DOIUrl":"https://doi.org/10.1109/EMPD.1995.500734","url":null,"abstract":"The traditional energy management system (EMS) has, until recently, remained isolated from other electric utility information systems, putting limits on its potential to the power company. Today, information technology (IT) can offer efficient and cost-justified solutions for the integration of these resources, and the value of IT is being increasingly recognized by many power companies. The current wave of privatisation, deregulation and market orientation of the electric energy market in many parts of the world has created new challenges. Power companies are now cast in the role of energy service companies instead of energy suppliers. The increasing competition and the requirements for improved overall economy and quality of services is accelerating the demand for more accurate and up-to-date information. Information has become a strategic resource. To exploit its full potential for all users, the keyword is integration. Technical, business and administrative applications need to be viewed in a corporate wide perspective. A revised IT strategy has become a tool for positioning the power company in a competitive market.","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":"129659985","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.1995.500697
J. Cornell
ACTEW Corp. has embarked on a series of pilot remote control and operations schemes to evaluate potential distribution system automation (DSA) operational philosophies in the national capital city of Australia, Canberra. In commercial districts which essentially comprise ring main unit connected underground circuits with some tee'd cross connections, ACTEW (in partnership with private engineers) is developing a network of actuator-operated switches controlled via VHF radio-, or trunked radio-linked RTUs. Domestic districts are reticulated by feeders which combine multiply-interspersed overhead and underground sections. To automate this arrangement, the philosophy must accommodate this diversity of circuitry and is being addressed by a combination of pole-mounted switches (on the overhead sections) and actuator operated switches on the underground sections. All operating philosophies are being trialed in a "remote control" mode before full automation is attempted.
{"title":"Philosophy for operation of distribution system automation schemes: ACTEW's approach","authors":"J. Cornell","doi":"10.1109/EMPD.1995.500697","DOIUrl":"https://doi.org/10.1109/EMPD.1995.500697","url":null,"abstract":"ACTEW Corp. has embarked on a series of pilot remote control and operations schemes to evaluate potential distribution system automation (DSA) operational philosophies in the national capital city of Australia, Canberra. In commercial districts which essentially comprise ring main unit connected underground circuits with some tee'd cross connections, ACTEW (in partnership with private engineers) is developing a network of actuator-operated switches controlled via VHF radio-, or trunked radio-linked RTUs. Domestic districts are reticulated by feeders which combine multiply-interspersed overhead and underground sections. To automate this arrangement, the philosophy must accommodate this diversity of circuitry and is being addressed by a combination of pole-mounted switches (on the overhead sections) and actuator operated switches on the underground sections. All operating philosophies are being trialed in a \"remote control\" mode before full automation is attempted.","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":"124898653","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.1995.500756
Dai-Seub Choi, Chang-Suk Kim, J. Hasegawa
Network reconfiguration in distribution systems is realized by changing the status of sectionalizing switches, and is usually done for loss reduction or for load balancing in the power system. This paper presents a new method which applies a genetic algorithm to determine which sectionalizing switch to operate in order to solve the distribution system loss minimization reconfiguration problem. In addition, the proposed method introduces a new limited life feature for performing natural selection of individuals. Simulations are carried out in order to verify the effectiveness of the proposed method. These results show that the proposed method is effective in dealing with the problems of homogeneity and genetic drift associated with the population in the initial state.
{"title":"An application of genetic algorithms to the network reconfiguration in distribution for loss minimization and load balancing problem. II","authors":"Dai-Seub Choi, Chang-Suk Kim, J. Hasegawa","doi":"10.1109/EMPD.1995.500756","DOIUrl":"https://doi.org/10.1109/EMPD.1995.500756","url":null,"abstract":"Network reconfiguration in distribution systems is realized by changing the status of sectionalizing switches, and is usually done for loss reduction or for load balancing in the power system. This paper presents a new method which applies a genetic algorithm to determine which sectionalizing switch to operate in order to solve the distribution system loss minimization reconfiguration problem. In addition, the proposed method introduces a new limited life feature for performing natural selection of individuals. Simulations are carried out in order to verify the effectiveness of the proposed method. These results show that the proposed method is effective in dealing with the problems of homogeneity and genetic drift associated with the population in the initial state.","PeriodicalId":447674,"journal":{"name":"Proceedings 1995 International Conference on Energy Management and Power Delivery EMPD '95","volume":"50 14 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":"121282976","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.1995.500766
S. K. Wong, Akhtar Kalam
This paper presents an approach to the development of a system for the design, analysis and assessment of power protection schemes. The system aims to assist the protection experts in automating their work and aids them in diagnosing, planning and remembering. The system could also be used as a teaching or a training tool for the inexperienced fresh graduates in the field. Protection for a power system can be viewed as a sum of coordinated protective devices located in the various parts of a power system. The design of protection schemes depends on the configuration of the system, the specifications the system must meet and the constraints that must be satisfied. Selecting and setting the appropriate relays and protective devices are no easy tasks and require skill, experience, heuristics and common sense knowledge. This paper presents a generic architecture based on multi agent paradigm and introduces a novel approach in the development of an intelligent system. It uses a distributed problem solving technique and integrates different reasoning methodologies such as case based, rule based and explanation based. The architecture of the system is based on an object oriented paradigm and utilises a multi knowledge representation scheme in a case based framework. Part of the system which has been implemented in an object oriented environment shows a promising and convincing demonstration of the system's architecture and approach.
{"title":"Development of a power protection system using an agent based architecture","authors":"S. K. Wong, Akhtar Kalam","doi":"10.1109/EMPD.1995.500766","DOIUrl":"https://doi.org/10.1109/EMPD.1995.500766","url":null,"abstract":"This paper presents an approach to the development of a system for the design, analysis and assessment of power protection schemes. The system aims to assist the protection experts in automating their work and aids them in diagnosing, planning and remembering. The system could also be used as a teaching or a training tool for the inexperienced fresh graduates in the field. Protection for a power system can be viewed as a sum of coordinated protective devices located in the various parts of a power system. The design of protection schemes depends on the configuration of the system, the specifications the system must meet and the constraints that must be satisfied. Selecting and setting the appropriate relays and protective devices are no easy tasks and require skill, experience, heuristics and common sense knowledge. This paper presents a generic architecture based on multi agent paradigm and introduces a novel approach in the development of an intelligent system. It uses a distributed problem solving technique and integrates different reasoning methodologies such as case based, rule based and explanation based. The architecture of the system is based on an object oriented paradigm and utilises a multi knowledge representation scheme in a case based framework. Part of the system which has been implemented in an object oriented environment shows a promising and convincing demonstration of the system's architecture and approach.","PeriodicalId":447674,"journal":{"name":"Proceedings 1995 International Conference on Energy Management and Power Delivery EMPD '95","volume":"9 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":"128686998","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.1995.500809
M. Nagpal, M. S. Sachdev, Kao Ning, L.M. Wedephol
A new method of using artificial neural networks (ANN) to identify the magnetizing inrush currents that may occur in transformers during start-up is developed in this paper. The method is based on the fact that magnetizing inrush current has large harmonic components. Using the backpropagation algorithm, a feedforward neural network (FFNN) has been trained to discriminate between transformer magnetizing inrush and no-inrush currents. The trained network was verified using test data from a laboratory transformer. Results presented in this paper indicate that the ANN based inrush detector is efficient with good performance and reliability.
{"title":"Using a neural network for transformer protection","authors":"M. Nagpal, M. S. Sachdev, Kao Ning, L.M. Wedephol","doi":"10.1109/EMPD.1995.500809","DOIUrl":"https://doi.org/10.1109/EMPD.1995.500809","url":null,"abstract":"A new method of using artificial neural networks (ANN) to identify the magnetizing inrush currents that may occur in transformers during start-up is developed in this paper. The method is based on the fact that magnetizing inrush current has large harmonic components. Using the backpropagation algorithm, a feedforward neural network (FFNN) has been trained to discriminate between transformer magnetizing inrush and no-inrush currents. The trained network was verified using test data from a laboratory transformer. Results presented in this paper indicate that the ANN based inrush detector is efficient with good performance and reliability.","PeriodicalId":447674,"journal":{"name":"Proceedings 1995 International Conference on Energy Management and Power Delivery EMPD '95","volume":"41 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":"124211073","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.1995.500755
P. Dash, A. Routray, S. K. Panda, A. Liew
The paper introduces different types of fuzzy tuning methods for the controller parameters of the firing and extinction angle controller of an HVDC link. The test system, a point to point DC link, has been subjected to various small and large disturbances to examine the effectiveness of the proposed schemes. The current error and it's derivative in case of rectifier and the gamma error and it's derivative in case of the inverter are taken as the two principal signals to generate the change in the proportional and the integral gains according to a definite rule base. The results obtained have been compared graphically to prove the superiority of the proposed controllers.
{"title":"Fuzzy tuning of DC link controllers","authors":"P. Dash, A. Routray, S. K. Panda, A. Liew","doi":"10.1109/EMPD.1995.500755","DOIUrl":"https://doi.org/10.1109/EMPD.1995.500755","url":null,"abstract":"The paper introduces different types of fuzzy tuning methods for the controller parameters of the firing and extinction angle controller of an HVDC link. The test system, a point to point DC link, has been subjected to various small and large disturbances to examine the effectiveness of the proposed schemes. The current error and it's derivative in case of rectifier and the gamma error and it's derivative in case of the inverter are taken as the two principal signals to generate the change in the proportional and the integral gains according to a definite rule base. The results obtained have been compared graphically to prove the superiority of the proposed controllers.","PeriodicalId":447674,"journal":{"name":"Proceedings 1995 International Conference on Energy Management and Power Delivery EMPD '95","volume":"2006 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":"116934105","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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