Pub Date : 1989-10-15DOI: 10.1109/INTLEC.1989.88301
F. Schneider
After discussing basic ideas concerning the reliability of UPS (uninterruptible power supply) systems, the authors present reliability parameters and formulae, reliability formulae for down-times of short mains, reliability formulae for down-times for long mains, and reliability formulae for the entire power supply system. To give an idea of the reliability values that can be reached in uninterruptible power supply systems and of the factors by which these values are affected, a number of examples are calculated by means of the derived formulae.<>
{"title":"Reliability of uninterruptible power supply systems","authors":"F. Schneider","doi":"10.1109/INTLEC.1989.88301","DOIUrl":"https://doi.org/10.1109/INTLEC.1989.88301","url":null,"abstract":"After discussing basic ideas concerning the reliability of UPS (uninterruptible power supply) systems, the authors present reliability parameters and formulae, reliability formulae for down-times of short mains, reliability formulae for down-times for long mains, and reliability formulae for the entire power supply system. To give an idea of the reliability values that can be reached in uninterruptible power supply systems and of the factors by which these values are affected, a number of examples are calculated by means of the derived formulae.<<ETX>>","PeriodicalId":272740,"journal":{"name":"Conference Proceedings., Eleventh International Telecommunications Energy Conference","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129851101","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 : 1989-10-15DOI: 10.1109/INTLEC.1989.88297
J. M. Castellanos
The author traces the origin, development, and technical features of protection devices for transient overvoltages that come in through the power distribution line to remote and unattended small-capacity commutating power plants of the Telefonica system. The currently used devices are a reliable solution of the AC continuous supply to telephone power plants which, because of their geographical location, are exposed to line unbalances, primarily as the result of storms.<>
{"title":"Protections for remote and unattended small capacity commutating power plants at 'Telefonica'","authors":"J. M. Castellanos","doi":"10.1109/INTLEC.1989.88297","DOIUrl":"https://doi.org/10.1109/INTLEC.1989.88297","url":null,"abstract":"The author traces the origin, development, and technical features of protection devices for transient overvoltages that come in through the power distribution line to remote and unattended small-capacity commutating power plants of the Telefonica system. The currently used devices are a reliable solution of the AC continuous supply to telephone power plants which, because of their geographical location, are exposed to line unbalances, primarily as the result of storms.<<ETX>>","PeriodicalId":272740,"journal":{"name":"Conference Proceedings., Eleventh International Telecommunications Energy Conference","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129977534","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 : 1989-10-15DOI: 10.1109/INTLEC.1989.88356
A.S. Kislovski
The author describes an LVI (linear variable inductor) current sensor proposed for high-reliability solar-powered telecommunication battery chargers. Its design principle and implementation are discussed. In the proposed LVI sensor, high sensitivity at low current has been achieved by applying a prepolarization field to the sensor core structure. This sensor is shown to be superior to the other possible candidates with respect to the decisive qualities in the particular application considered, i.e. simplicity, reliability, high efficiency, and low cost.<>
{"title":"Linear variable inductor in DC current sensors utilized in telecom solar battery chargers","authors":"A.S. Kislovski","doi":"10.1109/INTLEC.1989.88356","DOIUrl":"https://doi.org/10.1109/INTLEC.1989.88356","url":null,"abstract":"The author describes an LVI (linear variable inductor) current sensor proposed for high-reliability solar-powered telecommunication battery chargers. Its design principle and implementation are discussed. In the proposed LVI sensor, high sensitivity at low current has been achieved by applying a prepolarization field to the sensor core structure. This sensor is shown to be superior to the other possible candidates with respect to the decisive qualities in the particular application considered, i.e. simplicity, reliability, high efficiency, and low cost.<<ETX>>","PeriodicalId":272740,"journal":{"name":"Conference Proceedings., Eleventh International Telecommunications Energy Conference","volume":"78 2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116583822","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 : 1989-10-15DOI: 10.1109/INTLEC.1989.88273
J. A. O'Connor
The author describes a new small DC power system that employs an aluminum air battery as an emergency standby reserve, in a dual reserve configuration. The background to the development is presented along with a simplified description of the system operation. Also considered are the influence of the aluminum air battery on the converter and the system efficiency and reliability.<>
{"title":"A new dual reserve power system for small telephone exchanges","authors":"J. A. O'Connor","doi":"10.1109/INTLEC.1989.88273","DOIUrl":"https://doi.org/10.1109/INTLEC.1989.88273","url":null,"abstract":"The author describes a new small DC power system that employs an aluminum air battery as an emergency standby reserve, in a dual reserve configuration. The background to the development is presented along with a simplified description of the system operation. Also considered are the influence of the aluminum air battery on the converter and the system efficiency and reliability.<<ETX>>","PeriodicalId":272740,"journal":{"name":"Conference Proceedings., Eleventh International Telecommunications Energy Conference","volume":"94 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124263180","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 : 1989-10-15DOI: 10.1109/INTLEC.1989.88326
A. Ascoli
As part of a wide on-site fuel-cell generator demonstration, 40 kW fuel cell systems were installed in 49 installations, including a telephone central office building in Connecticut. The authors describe the Connecticut installation and summarize the results of the demonstration project. The average operating time of the power plants was 6500 hours. One-third of the plants exceeding 8000 hours of operation, with the longest running unit operating for over 11000 hours. Total operating experience exceeded 300000 hours. Overall and electrical efficiencies were outstandingly stable over 8000 hours of operation with electrical at (40+or-1)% and overall at (70+or-10)%, with no visible performance degradation. This field test successfully demonstrated the features of utilities to host, operate, and maintain the equipment. High efficiency, low environmental impact quick load-variation response, performance stability, and suitability to power telephone switching equipment were demonstrated.<>
{"title":"Fuel cell generator for telephone switching equipment","authors":"A. Ascoli","doi":"10.1109/INTLEC.1989.88326","DOIUrl":"https://doi.org/10.1109/INTLEC.1989.88326","url":null,"abstract":"As part of a wide on-site fuel-cell generator demonstration, 40 kW fuel cell systems were installed in 49 installations, including a telephone central office building in Connecticut. The authors describe the Connecticut installation and summarize the results of the demonstration project. The average operating time of the power plants was 6500 hours. One-third of the plants exceeding 8000 hours of operation, with the longest running unit operating for over 11000 hours. Total operating experience exceeded 300000 hours. Overall and electrical efficiencies were outstandingly stable over 8000 hours of operation with electrical at (40+or-1)% and overall at (70+or-10)%, with no visible performance degradation. This field test successfully demonstrated the features of utilities to host, operate, and maintain the equipment. High efficiency, low environmental impact quick load-variation response, performance stability, and suitability to power telephone switching equipment were demonstrated.<<ETX>>","PeriodicalId":272740,"journal":{"name":"Conference Proceedings., Eleventh International Telecommunications Energy Conference","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125121011","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 : 1989-10-15DOI: 10.1109/INTLEC.1989.88261
M. Cadre, A. Viault
The THEBES software package was especially written to simulate air flows in electronic devices cooled by natural or forced convection, such as telecommunication racks, computers, or large electrical equipment. THEBES consists of four modules. The first module deals with management of the printed-circuit-board databank and of the fan databank while the second module is used to enter the geometrical, thermal, and hydraulic data for the equipment under study. The third module computes the 3-D Napier-Stokes equations, and the mass and energy equations, while the last module deals with the visualization of the results of simulation such as air velocity and temperature. The equipment under study is automatically meshed during the preprocessing of the data. The geometry is entered interactively through the description of 'objects' such as printed circuits boards, metal sheets, openings, fans, and 3-D obstacles. The description of the air flow in the electronic device is useful not only for comparison between different designs but also to locate hot spots or to study the impact of the modification on mechanical parts. The authors describe the capabilities of the software and its field of application. Examples of thermal optimization studies are given for a 19 inch rack and for a transmission slimrack.<>
{"title":"Thermal simulations for electronic equipment using the software package THEBES","authors":"M. Cadre, A. Viault","doi":"10.1109/INTLEC.1989.88261","DOIUrl":"https://doi.org/10.1109/INTLEC.1989.88261","url":null,"abstract":"The THEBES software package was especially written to simulate air flows in electronic devices cooled by natural or forced convection, such as telecommunication racks, computers, or large electrical equipment. THEBES consists of four modules. The first module deals with management of the printed-circuit-board databank and of the fan databank while the second module is used to enter the geometrical, thermal, and hydraulic data for the equipment under study. The third module computes the 3-D Napier-Stokes equations, and the mass and energy equations, while the last module deals with the visualization of the results of simulation such as air velocity and temperature. The equipment under study is automatically meshed during the preprocessing of the data. The geometry is entered interactively through the description of 'objects' such as printed circuits boards, metal sheets, openings, fans, and 3-D obstacles. The description of the air flow in the electronic device is useful not only for comparison between different designs but also to locate hot spots or to study the impact of the modification on mechanical parts. The authors describe the capabilities of the software and its field of application. Examples of thermal optimization studies are given for a 19 inch rack and for a transmission slimrack.<<ETX>>","PeriodicalId":272740,"journal":{"name":"Conference Proceedings., Eleventh International Telecommunications Energy Conference","volume":"75 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124452288","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 : 1989-10-15DOI: 10.1109/INTLEC.1989.88262
B. Ulrich
The author describes a modular liquid-cooled packaging design based primarily on heat conduction principles (abandonment of natural air convection). It is being used both in an existing Telex exchange design and in trials with a pilot AC/DC power supply system (MS 2000 with water-cooled rectifiers) using a water chiller designed according to the Ascom concept. Energy consumption measurements using the water chiller prototype show even at this early stage that this cooling concept can achieve energy savings that are far from trivial.<>
{"title":"An advanced telecom packaging concept ensuring higher reliability and low cooling energy costs","authors":"B. Ulrich","doi":"10.1109/INTLEC.1989.88262","DOIUrl":"https://doi.org/10.1109/INTLEC.1989.88262","url":null,"abstract":"The author describes a modular liquid-cooled packaging design based primarily on heat conduction principles (abandonment of natural air convection). It is being used both in an existing Telex exchange design and in trials with a pilot AC/DC power supply system (MS 2000 with water-cooled rectifiers) using a water chiller designed according to the Ascom concept. Energy consumption measurements using the water chiller prototype show even at this early stage that this cooling concept can achieve energy savings that are far from trivial.<<ETX>>","PeriodicalId":272740,"journal":{"name":"Conference Proceedings., Eleventh International Telecommunications Energy Conference","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130081853","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 : 1989-10-15DOI: 10.1109/INTLEC.1989.88353
D. Heinemann, J. Luther, W. Wiesner
The authors report on simulation calculations carried out to determine the system configuration of an autonomous renewable power supply for a remote ecological station monitoring concentrations of O/sub 3/ and NO/sub 2/. The system has a mean electric load of 100-120 W, is powered by photovoltaics and a wind-energy converter, and includes a Pb-battery storage. No backup energy source is used. The same system design should be valid for telecommunication stations having a power demand in the same range. Although the given site is characterized by a rather poor wind climate (v/sub 10m/=3.7 m/s), the utilization of two to-some-extent complementary energy sources leads to a considerable saving in hardware investments. the levelling of the energy production is beneficial for the system's battery. Only 30-35% of the load is supplied by the battery, thus yielding a low effective cycling rate which extends the lifetime of the battery. Load management strategies may improve the matching of load profile and renewable energy production considerably. Reductions in system hardware up to a factor of 2 (depending on the applied strategy) are possible.<>
{"title":"Design of a solar/wind power supply for a remote data acquisition station","authors":"D. Heinemann, J. Luther, W. Wiesner","doi":"10.1109/INTLEC.1989.88353","DOIUrl":"https://doi.org/10.1109/INTLEC.1989.88353","url":null,"abstract":"The authors report on simulation calculations carried out to determine the system configuration of an autonomous renewable power supply for a remote ecological station monitoring concentrations of O/sub 3/ and NO/sub 2/. The system has a mean electric load of 100-120 W, is powered by photovoltaics and a wind-energy converter, and includes a Pb-battery storage. No backup energy source is used. The same system design should be valid for telecommunication stations having a power demand in the same range. Although the given site is characterized by a rather poor wind climate (v/sub 10m/=3.7 m/s), the utilization of two to-some-extent complementary energy sources leads to a considerable saving in hardware investments. the levelling of the energy production is beneficial for the system's battery. Only 30-35% of the load is supplied by the battery, thus yielding a low effective cycling rate which extends the lifetime of the battery. Load management strategies may improve the matching of load profile and renewable energy production considerably. Reductions in system hardware up to a factor of 2 (depending on the applied strategy) are possible.<<ETX>>","PeriodicalId":272740,"journal":{"name":"Conference Proceedings., Eleventh International Telecommunications Energy Conference","volume":"71 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129087470","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 : 1989-10-15DOI: 10.1109/INTLEC.1989.88334
H. Mickal, H. Tappeiner
The concept referred to as a triport of a utility-interactive UPS (uninterruptible power supply) is explained. It has a simple and cost-effective structure and enables a low-cost UPS to be designed with all required UPS features, particularly for single-phase UPSs in the 1-10 kVA power range. The different features in comparison to traditional UPSs are briefly discussed, e.g. voltage and frequency tolerance and utility failures. Results and experience with field operation are illustrated by oscillograms and diagrams.<>
{"title":"Experiences with UPSes in active stand-by operation","authors":"H. Mickal, H. Tappeiner","doi":"10.1109/INTLEC.1989.88334","DOIUrl":"https://doi.org/10.1109/INTLEC.1989.88334","url":null,"abstract":"The concept referred to as a triport of a utility-interactive UPS (uninterruptible power supply) is explained. It has a simple and cost-effective structure and enables a low-cost UPS to be designed with all required UPS features, particularly for single-phase UPSs in the 1-10 kVA power range. The different features in comparison to traditional UPSs are briefly discussed, e.g. voltage and frequency tolerance and utility failures. Results and experience with field operation are illustrated by oscillograms and diagrams.<<ETX>>","PeriodicalId":272740,"journal":{"name":"Conference Proceedings., Eleventh International Telecommunications Energy Conference","volume":"87 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122468125","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 : 1989-10-15DOI: 10.1109/INTLEC.1989.88271
J. Perho, N. Hoglund, P. Taskinen
Fault connections and leakages often occur in the TN-S partly due to the network itself and partly due to defective devices. These faults do not cause disturbances in the energy supply but do cause other disturbing influences, e.g. large potential differences between distinct equipment earths, electromagnetic disturbances, and the possibility that high-frequency disturbance voltages in the neutral conductor may penetrate into the protective earthing. By the continuous supervision of the TN-S network the disturbances mentioned before can be eliminated and a fault connection or a faulty device located easily. For the continuous supervision of the TN-S network, several supervising devices have been developed, which use sum current transformers. Good results have been achieved by the correct placement of the supervising devices and a detailed analysis of the network.<>
{"title":"AC network as a TN-S system and its supervising","authors":"J. Perho, N. Hoglund, P. Taskinen","doi":"10.1109/INTLEC.1989.88271","DOIUrl":"https://doi.org/10.1109/INTLEC.1989.88271","url":null,"abstract":"Fault connections and leakages often occur in the TN-S partly due to the network itself and partly due to defective devices. These faults do not cause disturbances in the energy supply but do cause other disturbing influences, e.g. large potential differences between distinct equipment earths, electromagnetic disturbances, and the possibility that high-frequency disturbance voltages in the neutral conductor may penetrate into the protective earthing. By the continuous supervision of the TN-S network the disturbances mentioned before can be eliminated and a fault connection or a faulty device located easily. For the continuous supervision of the TN-S network, several supervising devices have been developed, which use sum current transformers. Good results have been achieved by the correct placement of the supervising devices and a detailed analysis of the network.<<ETX>>","PeriodicalId":272740,"journal":{"name":"Conference Proceedings., Eleventh International Telecommunications Energy Conference","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123168684","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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