Pub Date : 1995-05-07DOI: 10.1109/ICPS.1995.527002
U. Grasselli
A general purpose Emergency Generator Set (EGS) is considered for a methodological study and related reliability behaviour is analyzed. In particular in a procedure of reliability and availability analysis of a EGS, dependent failure events need a complex mathematical model as “state-space model” to be a accurately evaluated. Furthermore these dependent failure events are one of the most important reliability characteristic of EGS. This paper suggests a procedure for reliability calculations in presence of dependent failure based on the evaluation of a equivalent failure rate that can be fitted to a network reduction method by simple mathematical calculations. The simplified models analyzed show a good accuracy for a wide range of variation of main reliability characteristics of EGS and utility. The advantages obtained are very useful on reliability evaluation because the possibility of use of network approach provides a shorter route to calculation and it is applicable by a larger number of power system designers.
{"title":"Comparison between different procedures of reliability analysis for emergency and stand-by power systems","authors":"U. Grasselli","doi":"10.1109/ICPS.1995.527002","DOIUrl":"https://doi.org/10.1109/ICPS.1995.527002","url":null,"abstract":"A general purpose Emergency Generator Set (EGS) is considered for a methodological study and related reliability behaviour is analyzed. In particular in a procedure of reliability and availability analysis of a EGS, dependent failure events need a complex mathematical model as “state-space model” to be a accurately evaluated. Furthermore these dependent failure events are one of the most important reliability characteristic of EGS. This paper suggests a procedure for reliability calculations in presence of dependent failure based on the evaluation of a equivalent failure rate that can be fitted to a network reduction method by simple mathematical calculations. The simplified models analyzed show a good accuracy for a wide range of variation of main reliability characteristics of EGS and utility. The advantages obtained are very useful on reliability evaluation because the possibility of use of network approach provides a shorter route to calculation and it is applicable by a larger number of power system designers.","PeriodicalId":138670,"journal":{"name":"Proceedings of 1995 Industrial and Commercial Power Systems Conference","volume":"188 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117284373","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 : 1995-05-07DOI: 10.1109/ICPS.1995.526995
H. Sarmiento, C. Tovar, E. Molero
In relatively weak electrical networks, that is, those with sparse interconnection between them; a fault occurring in any part of the network causes voltage sags to appear in different nodes, more severely in those adjacent to the fault. This occurs at every voltage level in an electrical network. Particularly so in distribution systems, when radial feeders originate from a same substation. In this case, a fault in one of the feeders will produce a voltage sag at the substation bus, thus affecting adjacent feeders. If any of these feeders supplies sensitive loads, like adjustable speed drives, PLC`S, computer systems, etc.; problems may arise at the customer loads where these voltage sags are seen as interruptions. It is suggested that a way to reduce these voltage sags to acceptable values can be achieved by limiting the fault current in the distribution feeders. A fault current limiter is defined as a series device that presents a low impedance to steady state currents, but acts quickly to limit the instantaneous magnitude of a fault current to a predetermined value. Many new fault current limiters (FCL) have been proposed lately in the literature but for this feasibility study a FCL of the LC resonantmore » link type was chosen for its simplicity.« less
{"title":"A feasibility study for a fault current limiter to reduce voltage sags at sensible loads","authors":"H. Sarmiento, C. Tovar, E. Molero","doi":"10.1109/ICPS.1995.526995","DOIUrl":"https://doi.org/10.1109/ICPS.1995.526995","url":null,"abstract":"In relatively weak electrical networks, that is, those with sparse interconnection between them; a fault occurring in any part of the network causes voltage sags to appear in different nodes, more severely in those adjacent to the fault. This occurs at every voltage level in an electrical network. Particularly so in distribution systems, when radial feeders originate from a same substation. In this case, a fault in one of the feeders will produce a voltage sag at the substation bus, thus affecting adjacent feeders. If any of these feeders supplies sensitive loads, like adjustable speed drives, PLC`S, computer systems, etc.; problems may arise at the customer loads where these voltage sags are seen as interruptions. It is suggested that a way to reduce these voltage sags to acceptable values can be achieved by limiting the fault current in the distribution feeders. A fault current limiter is defined as a series device that presents a low impedance to steady state currents, but acts quickly to limit the instantaneous magnitude of a fault current to a predetermined value. Many new fault current limiters (FCL) have been proposed lately in the literature but for this feasibility study a FCL of the LC resonantmore » link type was chosen for its simplicity.« less","PeriodicalId":138670,"journal":{"name":"Proceedings of 1995 Industrial and Commercial Power Systems Conference","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131347758","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 : 1995-05-07DOI: 10.1109/ICPS.1995.526986
Haozhong Cheng, H. Sasaki, N. Yorino
This paper proposes a new method for designing a group of single tuned filters for both harmonic current injection suppression and harmonic voltage distortion reduction and power factor correction. The proposed method is based on three purposes: (1) reduction of harmonic voltage distortion in the source terminals to an acceptable level, (2) suppression of harmonic current injection in the source terminals to an acceptable level, (3) improvement of power factor at the source terminals. To determine the size of the capacitor in a group of single tuned filters, three new NLP mathematical formulations will be introduced. The first is to suppress harmonic current injection within an acceptable level. The second is to minimize the fundamental reactive power output while reducing harmonic voltage distortion to an acceptable level. The third is to determine an optimal assignment of reactive power output based on the results of harmonic voltage reduction and power factor correction. This new method has been demonstrated for designing a group of single tuned filters and its validity has been successfully confirmed through numerical simulation in a 35 KV industrial power system. The proposed method can efficiently provide an optimal coordination in a group of single tuned filters relating tomore » suppressing harmonic current injection, reducing harmonic voltage distortion and improving power factor.« less
{"title":"A new method for both harmonic voltage and harmonic current suppression and power factor correction in industrial power systems","authors":"Haozhong Cheng, H. Sasaki, N. Yorino","doi":"10.1109/ICPS.1995.526986","DOIUrl":"https://doi.org/10.1109/ICPS.1995.526986","url":null,"abstract":"This paper proposes a new method for designing a group of single tuned filters for both harmonic current injection suppression and harmonic voltage distortion reduction and power factor correction. The proposed method is based on three purposes: (1) reduction of harmonic voltage distortion in the source terminals to an acceptable level, (2) suppression of harmonic current injection in the source terminals to an acceptable level, (3) improvement of power factor at the source terminals. To determine the size of the capacitor in a group of single tuned filters, three new NLP mathematical formulations will be introduced. The first is to suppress harmonic current injection within an acceptable level. The second is to minimize the fundamental reactive power output while reducing harmonic voltage distortion to an acceptable level. The third is to determine an optimal assignment of reactive power output based on the results of harmonic voltage reduction and power factor correction. This new method has been demonstrated for designing a group of single tuned filters and its validity has been successfully confirmed through numerical simulation in a 35 KV industrial power system. The proposed method can efficiently provide an optimal coordination in a group of single tuned filters relating tomore » suppressing harmonic current injection, reducing harmonic voltage distortion and improving power factor.« less","PeriodicalId":138670,"journal":{"name":"Proceedings of 1995 Industrial and Commercial Power Systems Conference","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114357978","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 : 1995-05-07DOI: 10.1109/ICPS.1995.527001
L. Tolbert, J. Cleveland, L. Degenhardt
An assessment of the 32 year historical reliability of the 13.8 kV electrical distribution system at the Oak Ridge National Laboratory (ORNL) in Tennessee has yielded several conclusions useful In the planning of Industrial power Systems. The system configuration at ORNL has essentially remained unchanged in the last 32 years which allows a meaningful comparison of reliability trends for the plant`s eight overhead distribution lines, two of which were built in the 1960`s with lightning resistant construction techniques. Meticulous records indicating the cause, duration, and location of 135 electric outages in the plant`s distribution system have allowed a reliability assessment to be performed. The assessment clearly shows how differences in voltage construction class, length, age, and maximum elevation above a reference elevation influence the reliability of overhead power distribution lines. Comparisons are also made between the ORNL historical data and predicted failure rates from ANSI and IEEE industry surveys.
{"title":"Reliability of lightning resistant overhead power distribution lines","authors":"L. Tolbert, J. Cleveland, L. Degenhardt","doi":"10.1109/ICPS.1995.527001","DOIUrl":"https://doi.org/10.1109/ICPS.1995.527001","url":null,"abstract":"An assessment of the 32 year historical reliability of the 13.8 kV electrical distribution system at the Oak Ridge National Laboratory (ORNL) in Tennessee has yielded several conclusions useful In the planning of Industrial power Systems. The system configuration at ORNL has essentially remained unchanged in the last 32 years which allows a meaningful comparison of reliability trends for the plant`s eight overhead distribution lines, two of which were built in the 1960`s with lightning resistant construction techniques. Meticulous records indicating the cause, duration, and location of 135 electric outages in the plant`s distribution system have allowed a reliability assessment to be performed. The assessment clearly shows how differences in voltage construction class, length, age, and maximum elevation above a reference elevation influence the reliability of overhead power distribution lines. Comparisons are also made between the ORNL historical data and predicted failure rates from ANSI and IEEE industry surveys.","PeriodicalId":138670,"journal":{"name":"Proceedings of 1995 Industrial and Commercial Power Systems Conference","volume":"467 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128401892","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 : 1995-05-07DOI: 10.1109/ICPS.1995.526994
G. Parise, F. Ferranti, R. Colozza
This paper discusses the need to study the criteria for the design and installation of electrical power systems in buildings subject to seismic hazards. Nowadays, all the recommended seismic requirements (according to the Uniform Building Code [UBC], Structural Engineers Association of California [SEAOC] and National Earthquake Hazards Reduction Program [NEHRP]) do not specifically take into account the electrical or technological power systems. This paper analyzes the problems an earthquake can cause with regard to the functional reliability and continuity of supply of electrical power systems. Therefore, it proposes design and installation requirements, to be graduated according to building occupancy categories. Basically, the criteria relative to the installation of the electrical equipment are an appropriate extension of those general static ones for nonstructural components. Their consideration is essential for the settlement of the design criteria, which, as far as the configuration and the size of the electrical power system are concerned, aim at limiting the same installation problems. Other general design criteria, designed as a guarantee for supply continuity and power system reliability, have a particular use in these appliances.
{"title":"Tentative criteria for the design and installation of electrical power systems subject to seismic hazard","authors":"G. Parise, F. Ferranti, R. Colozza","doi":"10.1109/ICPS.1995.526994","DOIUrl":"https://doi.org/10.1109/ICPS.1995.526994","url":null,"abstract":"This paper discusses the need to study the criteria for the design and installation of electrical power systems in buildings subject to seismic hazards. Nowadays, all the recommended seismic requirements (according to the Uniform Building Code [UBC], Structural Engineers Association of California [SEAOC] and National Earthquake Hazards Reduction Program [NEHRP]) do not specifically take into account the electrical or technological power systems. This paper analyzes the problems an earthquake can cause with regard to the functional reliability and continuity of supply of electrical power systems. Therefore, it proposes design and installation requirements, to be graduated according to building occupancy categories. Basically, the criteria relative to the installation of the electrical equipment are an appropriate extension of those general static ones for nonstructural components. Their consideration is essential for the settlement of the design criteria, which, as far as the configuration and the size of the electrical power system are concerned, aim at limiting the same installation problems. Other general design criteria, designed as a guarantee for supply continuity and power system reliability, have a particular use in these appliances.","PeriodicalId":138670,"journal":{"name":"Proceedings of 1995 Industrial and Commercial Power Systems Conference","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123337009","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.1995.527003
J. Fischer
Due to a misapplication of low-voltage power circuit breakers on high-cycling motor-starting services, the electrically operated mechanisms failed due to the large number of spring-charging, closing and opening cycles. Various options for correcting the problem were evaluated, and a vacuum contactor retrofit of the circuit breaker was selected for some of them. The vacuum starter units are electrically and mechanically interchangeable with the power circuit breakers. The paper discusses the design considerations and operating differences resulting from the technology conversion. It also discusses the differences in rating, function, and application
{"title":"Vacuum contactor retrofit of a low-voltage power circuit breaker","authors":"J. Fischer","doi":"10.1109/ICPS.1995.527003","DOIUrl":"https://doi.org/10.1109/ICPS.1995.527003","url":null,"abstract":"Due to a misapplication of low-voltage power circuit breakers on\u0000high-cycling motor-starting services, the electrically operated\u0000mechanisms failed due to the large number of spring-charging, closing\u0000and opening cycles. Various options for correcting the problem were\u0000evaluated, and a vacuum contactor retrofit of the circuit breaker was\u0000selected for some of them. The vacuum starter units are electrically and\u0000mechanically interchangeable with the power circuit breakers. The paper\u0000discusses the design considerations and operating differences resulting\u0000from the technology conversion. It also discusses the differences in\u0000rating, function, and application","PeriodicalId":138670,"journal":{"name":"Proceedings of 1995 Industrial and Commercial Power Systems Conference","volume":"20 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":"123759223","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.1995.526984
D. Shipp, W. Vilcheck
{"title":"Power quality and line considerations for variable speed AC drives","authors":"D. Shipp, W. Vilcheck","doi":"10.1109/ICPS.1995.526984","DOIUrl":"https://doi.org/10.1109/ICPS.1995.526984","url":null,"abstract":"","PeriodicalId":138670,"journal":{"name":"Proceedings of 1995 Industrial and Commercial Power Systems Conference","volume":"1 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":"120954194","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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