Pub Date : 2000-05-07DOI: 10.1109/REPCON.2000.848042
W. Kersting
A common requirement of a distribution system is to serve a combination of single-phase lighting loads and three-phase induction motors. Two transformer connections for providing this combination service are the ungrounded wye-delta and the open wye-open delta. Each connection has its good points and bad points. Of concern are the three-phase voltages provided the induction motor. If the voltages are unbalanced, depending upon the degree of unbalance, the induction motor is subject to overheating. Sources of the voltage unbalance can be the unequal spacing between conductors of the primary and secondary lines, the transformer ratings and connection and the amount of single-phase load relative to the three-phase load. This paper utilizes previously published models of the primary and secondary lines, transformer connections and induction motors. A simple system is developed to demonstrate the voltage unbalance created by these components under normal and abnormal conditions and the effect of the resulting unbalances on the induction motor. The system model also provides an insight into the voltages that can appear across the transformer terminals during abnormal operating conditions.
{"title":"Causes and effects of unbalanced voltages serving an induction motor","authors":"W. Kersting","doi":"10.1109/REPCON.2000.848042","DOIUrl":"https://doi.org/10.1109/REPCON.2000.848042","url":null,"abstract":"A common requirement of a distribution system is to serve a combination of single-phase lighting loads and three-phase induction motors. Two transformer connections for providing this combination service are the ungrounded wye-delta and the open wye-open delta. Each connection has its good points and bad points. Of concern are the three-phase voltages provided the induction motor. If the voltages are unbalanced, depending upon the degree of unbalance, the induction motor is subject to overheating. Sources of the voltage unbalance can be the unequal spacing between conductors of the primary and secondary lines, the transformer ratings and connection and the amount of single-phase load relative to the three-phase load. This paper utilizes previously published models of the primary and secondary lines, transformer connections and induction motors. A simple system is developed to demonstrate the voltage unbalance created by these components under normal and abnormal conditions and the effect of the resulting unbalances on the induction motor. The system model also provides an insight into the voltages that can appear across the transformer terminals during abnormal operating conditions.","PeriodicalId":306493,"journal":{"name":"2000 Rural Electric Power Conference. Papers Presented at the 44th Annual Conference (Cat. No.00CH37071)","volume":"83 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128012489","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 : 2000-05-07DOI: 10.1109/REPCON.2000.848054
J.S. Scaffer
Current limiting fuses have been commonly applied in protective systems for decades. They are effective for controlling peak currents and for limiting fault energy. Triggered current limiters (TCLs) are higher continuous current, electronically controlled variants of the more conventional technology. They are applied in the traditional current limiting fuse roles, but in addition, adapt readily to unique applications such as bypassing (shunting) current limiting reactors and closing system ties between adjacent buses. Bypassing reactors with TCLs can eliminate the continual losses and regulating voltage drop associated with current limiting reactors. This application provides full protection during a fault and load continuity following a fault. By closing system ties through a TCL the user may improve switching flexibility, better balance transformer loads, and/or start large motors with less system voltage sag. This paper investigates the practicality, the benefits and the limitations of TCLs in these specialized applications. It also introduces the concept of using TCLs for power quality enhancements on critical circuits where a bus fault may cripple an adjacent unfaulted bus.
{"title":"Triggered current limiters for closing bus ties, bypassing reactors and improving power quality","authors":"J.S. Scaffer","doi":"10.1109/REPCON.2000.848054","DOIUrl":"https://doi.org/10.1109/REPCON.2000.848054","url":null,"abstract":"Current limiting fuses have been commonly applied in protective systems for decades. They are effective for controlling peak currents and for limiting fault energy. Triggered current limiters (TCLs) are higher continuous current, electronically controlled variants of the more conventional technology. They are applied in the traditional current limiting fuse roles, but in addition, adapt readily to unique applications such as bypassing (shunting) current limiting reactors and closing system ties between adjacent buses. Bypassing reactors with TCLs can eliminate the continual losses and regulating voltage drop associated with current limiting reactors. This application provides full protection during a fault and load continuity following a fault. By closing system ties through a TCL the user may improve switching flexibility, better balance transformer loads, and/or start large motors with less system voltage sag. This paper investigates the practicality, the benefits and the limitations of TCLs in these specialized applications. It also introduces the concept of using TCLs for power quality enhancements on critical circuits where a bus fault may cripple an adjacent unfaulted bus.","PeriodicalId":306493,"journal":{"name":"2000 Rural Electric Power Conference. Papers Presented at the 44th Annual Conference (Cat. No.00CH37071)","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125138397","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 : 2000-05-07DOI: 10.1109/REPCON.2000.848053
J. Burr, H. James, C. Hamon
Resistivity measurements determine the number of chemically enhanced grounding rods needed to provide protection from lightning strikes and mechanical heating of electrical equipment. Soil physical properties such as texture, rock content, soil thickness, and water content determine resistivity and grounding potential. A study was initiated to (1) establish a database of electrical resistivity properties for several soil series in southwest Missouri, (2) correlate several soil properties to electrical resistivity, and (3) gather data to aid in determining the number of enhanced grounding rods needed at each site with electrical equipment. Recommendations made regarding installation of grounding rods have resulted in protection of electrical equipment at all sites.
{"title":"Soil properties, GPS, arcview, and soil resistivity provide tools for protecting electrical equipment from lightning and heat","authors":"J. Burr, H. James, C. Hamon","doi":"10.1109/REPCON.2000.848053","DOIUrl":"https://doi.org/10.1109/REPCON.2000.848053","url":null,"abstract":"Resistivity measurements determine the number of chemically enhanced grounding rods needed to provide protection from lightning strikes and mechanical heating of electrical equipment. Soil physical properties such as texture, rock content, soil thickness, and water content determine resistivity and grounding potential. A study was initiated to (1) establish a database of electrical resistivity properties for several soil series in southwest Missouri, (2) correlate several soil properties to electrical resistivity, and (3) gather data to aid in determining the number of enhanced grounding rods needed at each site with electrical equipment. Recommendations made regarding installation of grounding rods have resulted in protection of electrical equipment at all sites.","PeriodicalId":306493,"journal":{"name":"2000 Rural Electric Power Conference. Papers Presented at the 44th Annual Conference (Cat. No.00CH37071)","volume":"141 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115207937","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 : 2000-05-07DOI: 10.1109/REPCON.2000.848041
R. Morash, D. Friesen, R. Knick
Written-Pole(R) brand motors, generators and motor-generator sets have use of special interest for rural applications where single-phase distribution is predominant. These are based primarily on the large horsepower (10 to 75 or 100 hp) single-phase Written-Pole(R) motors. A number of advancements have been made in other areas also but this paper discusses three projects: (1) the internal rotor motor; (2) remote three-phase power sources; and (3) a power unit for center pivot irrigation systems.
{"title":"Advancements in Written-Pole(R) products for rural applications","authors":"R. Morash, D. Friesen, R. Knick","doi":"10.1109/REPCON.2000.848041","DOIUrl":"https://doi.org/10.1109/REPCON.2000.848041","url":null,"abstract":"Written-Pole(R) brand motors, generators and motor-generator sets have use of special interest for rural applications where single-phase distribution is predominant. These are based primarily on the large horsepower (10 to 75 or 100 hp) single-phase Written-Pole(R) motors. A number of advancements have been made in other areas also but this paper discusses three projects: (1) the internal rotor motor; (2) remote three-phase power sources; and (3) a power unit for center pivot irrigation systems.","PeriodicalId":306493,"journal":{"name":"2000 Rural Electric Power Conference. Papers Presented at the 44th Annual Conference (Cat. No.00CH37071)","volume":"120 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114499440","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 : 2000-05-07DOI: 10.1109/REPCON.2000.848046
M. S. Moore, S. Monemi, Jianfeng Wang, J. Marble, S. Jones
This paper presents a new decision support system that has been developed to aid electrical utilities in diagnosing, evaluating, and planning repairs of faults during service outages. The system, called the Integrated Distribution Management System (IDMS), provides both a diagnostics component and an easily configurable integration framework. The IDMS is a cost-effective solution for fault management in small to medium sized utilities.
{"title":"Diagnostics and integration in electric utilities","authors":"M. S. Moore, S. Monemi, Jianfeng Wang, J. Marble, S. Jones","doi":"10.1109/REPCON.2000.848046","DOIUrl":"https://doi.org/10.1109/REPCON.2000.848046","url":null,"abstract":"This paper presents a new decision support system that has been developed to aid electrical utilities in diagnosing, evaluating, and planning repairs of faults during service outages. The system, called the Integrated Distribution Management System (IDMS), provides both a diagnostics component and an easily configurable integration framework. The IDMS is a cost-effective solution for fault management in small to medium sized utilities.","PeriodicalId":306493,"journal":{"name":"2000 Rural Electric Power Conference. Papers Presented at the 44th Annual Conference (Cat. No.00CH37071)","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129963845","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 : 2000-05-07DOI: 10.1109/REPCON.2000.848035
B. D. Coate, D. Wareham
This paper presents a cost-effective method of reducing momentary interruptions. Two main concepts are discussed. The first is targeting selected zones with increased maintenance to improve overall reliability of the entire feeder, and the second is overcurrent coordination for trip saving on the substation feeder circuit breaker. Trip saving is the intentional coordination of tap fuses off main feeders so that a fault on the tap will not cause a fast operation of the main breaker. Other topics discussed are the re-setting of instantaneous tripping of the substation breaker, use of tap reclosers, and increasing lightning/animal protection on key parts of the feeder.
{"title":"Decreasing momentary outages with specific distribution feeder improvements","authors":"B. D. Coate, D. Wareham","doi":"10.1109/REPCON.2000.848035","DOIUrl":"https://doi.org/10.1109/REPCON.2000.848035","url":null,"abstract":"This paper presents a cost-effective method of reducing momentary interruptions. Two main concepts are discussed. The first is targeting selected zones with increased maintenance to improve overall reliability of the entire feeder, and the second is overcurrent coordination for trip saving on the substation feeder circuit breaker. Trip saving is the intentional coordination of tap fuses off main feeders so that a fault on the tap will not cause a fast operation of the main breaker. Other topics discussed are the re-setting of instantaneous tripping of the substation breaker, use of tap reclosers, and increasing lightning/animal protection on key parts of the feeder.","PeriodicalId":306493,"journal":{"name":"2000 Rural Electric Power Conference. Papers Presented at the 44th Annual Conference (Cat. No.00CH37071)","volume":"436 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133175116","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 : 2000-05-07DOI: 10.1109/REPCON.2000.848049
B. Maurhoff, G. Wood
In 1997, the management of a local golf resort/residential development asked for a meeting with Central Virginia Electric Cooperative (CVEC) to discuss power quality and reliability problems. The multi-million dollar development was located at the end of a 7 mile cross-country radial overhead distribution line. The line extended through a heavily wooded area for several miles before reaching the resort property. Three times in the previous twelve months, the resort had endured outages lasting longer than four hours, twice lasting longer than eight hours. Our standard 40 foot wide right-of-way was well maintained; the towering pine trees outside the right of way were the culprits. The property owners with pines would not allow wider clearing. The solution was to get a power source in close proximity to the development, but it was too close to the edge of the service territory and the load was too small to consider a new substation. The only good fit was an independent source that would be available quickly on loss of utility feed and could be used for periods of up to twenty-four hours. A standby diesel engine generator set was the answer, but the cost was prohibitive for CVEC to install one. The solution CVEC suggested was for the development to provide their own generator. If they were willing to operate it to offset peak power purchases for CVEC, they would receive monthly credits for its output that would offset the cost of ownership. This paper describes how the solution to the problem benefits all concerned.
{"title":"Dispersed generation-reduce power costs and improve service reliability","authors":"B. Maurhoff, G. Wood","doi":"10.1109/REPCON.2000.848049","DOIUrl":"https://doi.org/10.1109/REPCON.2000.848049","url":null,"abstract":"In 1997, the management of a local golf resort/residential development asked for a meeting with Central Virginia Electric Cooperative (CVEC) to discuss power quality and reliability problems. The multi-million dollar development was located at the end of a 7 mile cross-country radial overhead distribution line. The line extended through a heavily wooded area for several miles before reaching the resort property. Three times in the previous twelve months, the resort had endured outages lasting longer than four hours, twice lasting longer than eight hours. Our standard 40 foot wide right-of-way was well maintained; the towering pine trees outside the right of way were the culprits. The property owners with pines would not allow wider clearing. The solution was to get a power source in close proximity to the development, but it was too close to the edge of the service territory and the load was too small to consider a new substation. The only good fit was an independent source that would be available quickly on loss of utility feed and could be used for periods of up to twenty-four hours. A standby diesel engine generator set was the answer, but the cost was prohibitive for CVEC to install one. The solution CVEC suggested was for the development to provide their own generator. If they were willing to operate it to offset peak power purchases for CVEC, they would receive monthly credits for its output that would offset the cost of ownership. This paper describes how the solution to the problem benefits all concerned.","PeriodicalId":306493,"journal":{"name":"2000 Rural Electric Power Conference. Papers Presented at the 44th Annual Conference (Cat. No.00CH37071)","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131879212","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 : 2000-05-07DOI: 10.1109/REPCON.2000.848044
C.C. Landinger
The superior service reliability of aerial spacer cable systems in congested and heavily treed urban areas is a matter of record. Electric cooperatives having portions of their systems include such areas, either by territory acquisition or development, should be prepared to use covered wire systems to achieve the high degree of reliability demanded by today's customers. Even cooperatives remaining essentially rural at this time are seeing exclusive developments, such as lake shore property, which demand a high level of service reliability while minimizing environmental impact via massive tree removal. This paper describes the basic principles that confer superior reliability on aerial spacer cable systems and gives specific applications where they can be used to increase service reliability and quality. This increased reliability over that of bare wire systems can both reduce life cost and minimize impact on the local environment.
{"title":"Spacer cable systems for rural electric cooperatives","authors":"C.C. Landinger","doi":"10.1109/REPCON.2000.848044","DOIUrl":"https://doi.org/10.1109/REPCON.2000.848044","url":null,"abstract":"The superior service reliability of aerial spacer cable systems in congested and heavily treed urban areas is a matter of record. Electric cooperatives having portions of their systems include such areas, either by territory acquisition or development, should be prepared to use covered wire systems to achieve the high degree of reliability demanded by today's customers. Even cooperatives remaining essentially rural at this time are seeing exclusive developments, such as lake shore property, which demand a high level of service reliability while minimizing environmental impact via massive tree removal. This paper describes the basic principles that confer superior reliability on aerial spacer cable systems and gives specific applications where they can be used to increase service reliability and quality. This increased reliability over that of bare wire systems can both reduce life cost and minimize impact on the local environment.","PeriodicalId":306493,"journal":{"name":"2000 Rural Electric Power Conference. Papers Presented at the 44th Annual Conference (Cat. No.00CH37071)","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129842038","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 : 2000-05-07DOI: 10.1109/REPCON.2000.848040
Yingju Ren, Qijun Su
The Liu Chou Power Supply Bureau is a publicly owned rural electric distribution organization providing retail electric service to over 200,000 residential, irrigation and industrial customers in Southern China. A state-of-the-art load management information system, using the latest network technology, such as fast Ethernet and VLAN, is used to replace the old ones. This system not only retains compatibility with the original system, but also provides other specialties such as easy centralized management, performance optimization, system configuration, counting management, error recovery and security management. This paper describes the rural electrical bureau network architecture design, its information flow among the 150 nodes, 16 remote stations, network performance, configuration and counting management, with rich examples of SCADA.
{"title":"Network management system design for a large rural electric power bureau","authors":"Yingju Ren, Qijun Su","doi":"10.1109/REPCON.2000.848040","DOIUrl":"https://doi.org/10.1109/REPCON.2000.848040","url":null,"abstract":"The Liu Chou Power Supply Bureau is a publicly owned rural electric distribution organization providing retail electric service to over 200,000 residential, irrigation and industrial customers in Southern China. A state-of-the-art load management information system, using the latest network technology, such as fast Ethernet and VLAN, is used to replace the old ones. This system not only retains compatibility with the original system, but also provides other specialties such as easy centralized management, performance optimization, system configuration, counting management, error recovery and security management. This paper describes the rural electrical bureau network architecture design, its information flow among the 150 nodes, 16 remote stations, network performance, configuration and counting management, with rich examples of SCADA.","PeriodicalId":306493,"journal":{"name":"2000 Rural Electric Power Conference. Papers Presented at the 44th Annual Conference (Cat. No.00CH37071)","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121805263","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/REPCON.2000.848045
N. McCollough
Many rural electric co-operatives do not have extensive SCADA systems and some have none at all. Up front costs are often the primary deterrent to implementing such SCADA systems. As the number and type of remote communication devices on the market expand, new cost-effective solutions are becoming available to provide limited SCADA capability at a fraction of the cost. Such systems often use passive devices, which report by exception, rather than continuous two-way communication. These systems still allow immediate report and control on demand. Communication devices are only one leg of the SCADA program. Components on the system must be designed to collect the type of information needed by the utility. Fault location information, remote switch open and close operation, minimum/maximum feeder voltage readings, capacitor bank trip and close control, device status monitoring and load management information are examples of applications which are performed remotely.
{"title":"Remote communication devices for electric utility applications","authors":"N. McCollough","doi":"10.1109/REPCON.2000.848045","DOIUrl":"https://doi.org/10.1109/REPCON.2000.848045","url":null,"abstract":"Many rural electric co-operatives do not have extensive SCADA systems and some have none at all. Up front costs are often the primary deterrent to implementing such SCADA systems. As the number and type of remote communication devices on the market expand, new cost-effective solutions are becoming available to provide limited SCADA capability at a fraction of the cost. Such systems often use passive devices, which report by exception, rather than continuous two-way communication. These systems still allow immediate report and control on demand. Communication devices are only one leg of the SCADA program. Components on the system must be designed to collect the type of information needed by the utility. Fault location information, remote switch open and close operation, minimum/maximum feeder voltage readings, capacitor bank trip and close control, device status monitoring and load management information are examples of applications which are performed remotely.","PeriodicalId":306493,"journal":{"name":"2000 Rural Electric Power Conference. Papers Presented at the 44th Annual Conference (Cat. No.00CH37071)","volume":"164 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":"122053992","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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