Pub Date : 1994-05-01DOI: 10.1109/ICPS.1994.303547
G. Parise
For near to generator short-circuit analysis, it is well known that a rigorous calculation procedure requires the use of complex dynamic models of power system components. In most practical cases, however, it is sufficient to adopt simplified and standard based calculation methods. For these cases the paper suggests a new approach of the short-circuit models of power system components based on the "characteristic" currents method. The paper, at first, presents a short overview of the IEC Standard 909, assumed as reference for the proposed approach. The calculation assumptions and the simplifications of the IEC Standard are pointed out in order to evidence how the new approach proposed obtains conservative, but more accurate results. The "characteristic" currents procedure is successively applied to a sample network with external feeder and internal generation and with motor load. The same network is analyzed by means of the IEC procedure and by means of a computer program able to consider dynamic models of electrical equipment. A comparison among these approaches is carried out in order to validate the "characteristic" currents method.<>
{"title":"Near-to-generator short-circuit analysis in industrial and commercial power systems: the \"characteristic\" currents method","authors":"G. Parise","doi":"10.1109/ICPS.1994.303547","DOIUrl":"https://doi.org/10.1109/ICPS.1994.303547","url":null,"abstract":"For near to generator short-circuit analysis, it is well known that a rigorous calculation procedure requires the use of complex dynamic models of power system components. In most practical cases, however, it is sufficient to adopt simplified and standard based calculation methods. For these cases the paper suggests a new approach of the short-circuit models of power system components based on the \"characteristic\" currents method. The paper, at first, presents a short overview of the IEC Standard 909, assumed as reference for the proposed approach. The calculation assumptions and the simplifications of the IEC Standard are pointed out in order to evidence how the new approach proposed obtains conservative, but more accurate results. The \"characteristic\" currents procedure is successively applied to a sample network with external feeder and internal generation and with motor load. The same network is analyzed by means of the IEC procedure and by means of a computer program able to consider dynamic models of electrical equipment. A comparison among these approaches is carried out in order to validate the \"characteristic\" currents method.<<ETX>>","PeriodicalId":197013,"journal":{"name":"Proceedings of Industrial and Commercial Power Systems Conference","volume":"233 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133307509","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 : 1994-05-01DOI: 10.1109/ICPS.1994.303557
D.W. Egolf, A. Flechsig
Power transformers supplying nonsinusoidal load current often need to be derated. The ANSI/IEEE C57.110-1986 standard provides a method by which derating may be performed. However, derating only provides an estimate of remaining transformer capacity, since subsequent load may significantly change the relative harmonic current values. The contribution of this paper is to provide a clear guide that can be used in applying the standard. This paper is not meant to replace the standard but to supplement it by providing correct examples and simplified equations.<>
{"title":"Harmonics-transformer derating","authors":"D.W. Egolf, A. Flechsig","doi":"10.1109/ICPS.1994.303557","DOIUrl":"https://doi.org/10.1109/ICPS.1994.303557","url":null,"abstract":"Power transformers supplying nonsinusoidal load current often need to be derated. The ANSI/IEEE C57.110-1986 standard provides a method by which derating may be performed. However, derating only provides an estimate of remaining transformer capacity, since subsequent load may significantly change the relative harmonic current values. The contribution of this paper is to provide a clear guide that can be used in applying the standard. This paper is not meant to replace the standard but to supplement it by providing correct examples and simplified equations.<<ETX>>","PeriodicalId":197013,"journal":{"name":"Proceedings of Industrial and Commercial Power Systems Conference","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123830981","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 : 1994-05-01DOI: 10.1109/ICPS.1994.303575
M. Saied
This paper deals with the electromagnetic transients in transformer substations. The substation can have more than one transformer. Generally, these parallel-connected transformers can be of different sizes and neutral treatment. The substation is fed from a high voltage overhead transmission line (or cable). Emphasis is given to the substation terminal voltage, the transformers' neutral voltages (if their neutrals are not directly earthed) as well as the internal distribution of transient voltages along the transformers' windings. Following a typical external double-exponential surge voltage, the distributed parameter transient analysis is done in the s-domain, and then followed by a numerical Laplace inverse transform technique to get the distributions in time domain.<>
{"title":"Effect of transformer sizes and neutral treatments on the electromagnetic transients in transformer substations","authors":"M. Saied","doi":"10.1109/ICPS.1994.303575","DOIUrl":"https://doi.org/10.1109/ICPS.1994.303575","url":null,"abstract":"This paper deals with the electromagnetic transients in transformer substations. The substation can have more than one transformer. Generally, these parallel-connected transformers can be of different sizes and neutral treatment. The substation is fed from a high voltage overhead transmission line (or cable). Emphasis is given to the substation terminal voltage, the transformers' neutral voltages (if their neutrals are not directly earthed) as well as the internal distribution of transient voltages along the transformers' windings. Following a typical external double-exponential surge voltage, the distributed parameter transient analysis is done in the s-domain, and then followed by a numerical Laplace inverse transform technique to get the distributions in time domain.<<ETX>>","PeriodicalId":197013,"journal":{"name":"Proceedings of Industrial and Commercial Power Systems Conference","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122739867","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 : 1994-05-01DOI: 10.1109/ICPS.1994.303577
G. Stein
The paper demonstrates that the existing electricity supply no longer works well for many large industrial customers; that more competition in electricity markets is needed and that retail wheeling is necessary to make competition a reality.<>
{"title":"In search of competitive electricity supplies","authors":"G. Stein","doi":"10.1109/ICPS.1994.303577","DOIUrl":"https://doi.org/10.1109/ICPS.1994.303577","url":null,"abstract":"The paper demonstrates that the existing electricity supply no longer works well for many large industrial customers; that more competition in electricity markets is needed and that retail wheeling is necessary to make competition a reality.<<ETX>>","PeriodicalId":197013,"journal":{"name":"Proceedings of Industrial and Commercial Power Systems Conference","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127413747","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 : 1994-05-01DOI: 10.1109/ICPS.1994.303578
D. Koval, A. Chowdhury
The operating characteristics of generating units can vary quite significantly depending upon their available capacity states and how they are utilized by a power system in its response to demand cycles. The rated or full capacity of a generating unit may or may not be available (e.g., derated states due to forced or scheduled partial generating unit outages). The frequency and duration of these reduced capacity states significantly affects the performance of generating units and their utilization patterns within a power system. Based on the Canadian Electrical Association's and Alberta Power Limited's data collection systems, this paper presents the results of a statistical study of the continuous operation of several base loaded generating units over a period of 9 years and reveal the unique state transitions between available and nonavailable states and their frequency and duration of occurrence. The generator state characteristics and transitions between available and non-available states provide the essential data necessary for estimating the reliability parameters of generating units and a guide for the utilization of base load generator units and estimates of their probable available capacity states to meet demand cycles.<>
{"title":"Base load generator unit operating characteristics","authors":"D. Koval, A. Chowdhury","doi":"10.1109/ICPS.1994.303578","DOIUrl":"https://doi.org/10.1109/ICPS.1994.303578","url":null,"abstract":"The operating characteristics of generating units can vary quite significantly depending upon their available capacity states and how they are utilized by a power system in its response to demand cycles. The rated or full capacity of a generating unit may or may not be available (e.g., derated states due to forced or scheduled partial generating unit outages). The frequency and duration of these reduced capacity states significantly affects the performance of generating units and their utilization patterns within a power system. Based on the Canadian Electrical Association's and Alberta Power Limited's data collection systems, this paper presents the results of a statistical study of the continuous operation of several base loaded generating units over a period of 9 years and reveal the unique state transitions between available and nonavailable states and their frequency and duration of occurrence. The generator state characteristics and transitions between available and non-available states provide the essential data necessary for estimating the reliability parameters of generating units and a guide for the utilization of base load generator units and estimates of their probable available capacity states to meet demand cycles.<<ETX>>","PeriodicalId":197013,"journal":{"name":"Proceedings of Industrial and Commercial Power Systems Conference","volume":"139 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124400323","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 : 1994-05-01DOI: 10.1109/ICPS.1994.303549
J. Martinez, C. Dortolina
This paper presents the most important results obtained from several dynamic studies performed on industrial power systems, focusing on chemical and petrochemical power systems. The purpose is to determine appropriate load shedding schemes and to establish settings for the related protective schemes, such as the disconnection of transmission links by means of inverse power and underfrequency relays, which divide the system into several isolated subsystems in order to reduce severe load-generation unbalances, while acting together within the load shedding scheme of each subsystem. The simulations required were executed with a transient stability program to determine the dynamic performance of the power system during severe load-generation unbalances.<>
{"title":"Dynamic simulation studies on electric industrial systems for designing and adjusting load shedding schemes","authors":"J. Martinez, C. Dortolina","doi":"10.1109/ICPS.1994.303549","DOIUrl":"https://doi.org/10.1109/ICPS.1994.303549","url":null,"abstract":"This paper presents the most important results obtained from several dynamic studies performed on industrial power systems, focusing on chemical and petrochemical power systems. The purpose is to determine appropriate load shedding schemes and to establish settings for the related protective schemes, such as the disconnection of transmission links by means of inverse power and underfrequency relays, which divide the system into several isolated subsystems in order to reduce severe load-generation unbalances, while acting together within the load shedding scheme of each subsystem. The simulations required were executed with a transient stability program to determine the dynamic performance of the power system during severe load-generation unbalances.<<ETX>>","PeriodicalId":197013,"journal":{"name":"Proceedings of Industrial and Commercial Power Systems Conference","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134466905","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 : 1994-05-01DOI: 10.1109/ICPS.1994.303560
B. Prokuda
This paper describes a process of surveying facilities to identify power supply quality concerns. Harmonic mitigation and wiring and grounding issues pertaining to industrial and commercial customers are discussed in detail.<>
{"title":"Power quality site surveys for industrial and commercial buildings","authors":"B. Prokuda","doi":"10.1109/ICPS.1994.303560","DOIUrl":"https://doi.org/10.1109/ICPS.1994.303560","url":null,"abstract":"This paper describes a process of surveying facilities to identify power supply quality concerns. Harmonic mitigation and wiring and grounding issues pertaining to industrial and commercial customers are discussed in detail.<<ETX>>","PeriodicalId":197013,"journal":{"name":"Proceedings of Industrial and Commercial Power Systems Conference","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123415144","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 : 1994-05-01DOI: 10.1109/ICPS.1994.303589
C. N. Claar
A new section was added to the 1990 edition of the National Electrical Code (NEC). The section presented an optional method to calculate the size of a new restaurant's service entrance and main distribution panel. In most cases application of the optional method resulted in reduction in service entrance and main panel sizes when compared to standard methods. Some engineers, end users, and others expressed concern about this reduction in service entrance size especially when considering the high electrical demands associated with starting-up a restaurant when it opens for the day. A restaurant in Indiana, USA, was instrumented for a field test of cooking equipment. This test arrangement was utilized to collect one minute demand interval data for several weeks. The data was recorded during the summer when the restaurant annual peak demand occurred and during the time of the day when the peak demand usually occurred. The results of the case study show the relationship between one minute demands, 15 minute demands, and other time intervals. Continuous loads as defined by the NEC are discussed with respect to the one minute demand data. Associations with protective device time-current curves are also explored. It also recommends what additional research is necessary to obtain data and establish indisputable and conclusive results.<>
{"title":"A case study of main service short time demand intervals","authors":"C. N. Claar","doi":"10.1109/ICPS.1994.303589","DOIUrl":"https://doi.org/10.1109/ICPS.1994.303589","url":null,"abstract":"A new section was added to the 1990 edition of the National Electrical Code (NEC). The section presented an optional method to calculate the size of a new restaurant's service entrance and main distribution panel. In most cases application of the optional method resulted in reduction in service entrance and main panel sizes when compared to standard methods. Some engineers, end users, and others expressed concern about this reduction in service entrance size especially when considering the high electrical demands associated with starting-up a restaurant when it opens for the day. A restaurant in Indiana, USA, was instrumented for a field test of cooking equipment. This test arrangement was utilized to collect one minute demand interval data for several weeks. The data was recorded during the summer when the restaurant annual peak demand occurred and during the time of the day when the peak demand usually occurred. The results of the case study show the relationship between one minute demands, 15 minute demands, and other time intervals. Continuous loads as defined by the NEC are discussed with respect to the one minute demand data. Associations with protective device time-current curves are also explored. It also recommends what additional research is necessary to obtain data and establish indisputable and conclusive results.<<ETX>>","PeriodicalId":197013,"journal":{"name":"Proceedings of Industrial and Commercial Power Systems Conference","volume":"116 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123492131","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 : 1994-05-01DOI: 10.1109/ICPS.1994.303579
U. Grasselli
A reliability survey must be based on the greatest possible number of fronts, both to increase the validity of the survey and to make a critical comparison, whenever needed, between data referring to equipment of the same type but implemented, installed and used in slightly different ways. However, it was immediately noted that obtaining reliability databases created for this specific purpose is extremely hard and expensive, This paper shows how it is possible to obtain reliable information from data collections not having been directly created for this purpose. It is stressed that it is necessary to carefully assess the repercussions that the specific purpose for which the data have been collected may have on the validity of the very data. Through this type of investigation it is at times possible to process the data so that they may be used for reliability purposes.<>
{"title":"Reliability survey of standby generator by evaluation of maintenance service data","authors":"U. Grasselli","doi":"10.1109/ICPS.1994.303579","DOIUrl":"https://doi.org/10.1109/ICPS.1994.303579","url":null,"abstract":"A reliability survey must be based on the greatest possible number of fronts, both to increase the validity of the survey and to make a critical comparison, whenever needed, between data referring to equipment of the same type but implemented, installed and used in slightly different ways. However, it was immediately noted that obtaining reliability databases created for this specific purpose is extremely hard and expensive, This paper shows how it is possible to obtain reliable information from data collections not having been directly created for this purpose. It is stressed that it is necessary to carefully assess the repercussions that the specific purpose for which the data have been collected may have on the validity of the very data. Through this type of investigation it is at times possible to process the data so that they may be used for reliability purposes.<<ETX>>","PeriodicalId":197013,"journal":{"name":"Proceedings of Industrial and Commercial Power Systems Conference","volume":"82 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126175772","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 : 1900-01-01DOI: 10.1109/ICPS.1994.303585
The purpose of this paper is to provide information that can be used to evaluate the compatibility between the electric power supply system voltage sags and electronic control devices integrated into industrial processes. Example sag data and equipment sensitivities are presented and it is shown how to combine the data to determine the economic loss due to voltage sags. Tradeoffs and alternatives in the power system, equipment design, and process design are discussed to minimize the impact of sag induced disruptions.<>
{"title":"Electric power system compatibility with industrial process equipment. I. Voltage sags","authors":"","doi":"10.1109/ICPS.1994.303585","DOIUrl":"https://doi.org/10.1109/ICPS.1994.303585","url":null,"abstract":"The purpose of this paper is to provide information that can be used to evaluate the compatibility between the electric power supply system voltage sags and electronic control devices integrated into industrial processes. Example sag data and equipment sensitivities are presented and it is shown how to combine the data to determine the economic loss due to voltage sags. Tradeoffs and alternatives in the power system, equipment design, and process design are discussed to minimize the impact of sag induced disruptions.<<ETX>>","PeriodicalId":197013,"journal":{"name":"Proceedings of Industrial and Commercial Power Systems Conference","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124897401","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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