Pub Date : 1989-10-15DOI: 10.1109/INTLEC.1989.88361
R. Prudhoe, L. Doukas
Recently, Telecom Australia has pioneered practical cost-effective methods for using the relatively high latent heat of fusion of phase-change chemicals (PCC) to provide thermal storage reserve cooling and conservation of energy in the building environment. The authors identify and outline performance characteristics of currently used PCC systems. They also introduce a novel passive building-cooling system for special high-reliability applications in remote-area communication sites. Such a low-cost minimum-maintenance system combines a thermally transparent equipment room that will maintain equipment within satisfactory environmental limits for most of the year with a special PCC thermal storage unit to give additional reserve cooling on hot days. The cool PCC storage may be provided through either a small air-conditioner or a fresh-air cycle during times of cooler weather. Mention is made of PCCs that are currently available in Australia and their suitability for application in PCC systems. PCC systems that are successfully being used by Telecom as well as exploratory PCC systems that are being investigated are briefly reviewed.<>
{"title":"Temperature limiting systems for environmental reliability of telecommunication equipment enclosures","authors":"R. Prudhoe, L. Doukas","doi":"10.1109/INTLEC.1989.88361","DOIUrl":"https://doi.org/10.1109/INTLEC.1989.88361","url":null,"abstract":"Recently, Telecom Australia has pioneered practical cost-effective methods for using the relatively high latent heat of fusion of phase-change chemicals (PCC) to provide thermal storage reserve cooling and conservation of energy in the building environment. The authors identify and outline performance characteristics of currently used PCC systems. They also introduce a novel passive building-cooling system for special high-reliability applications in remote-area communication sites. Such a low-cost minimum-maintenance system combines a thermally transparent equipment room that will maintain equipment within satisfactory environmental limits for most of the year with a special PCC thermal storage unit to give additional reserve cooling on hot days. The cool PCC storage may be provided through either a small air-conditioner or a fresh-air cycle during times of cooler weather. Mention is made of PCCs that are currently available in Australia and their suitability for application in PCC systems. PCC systems that are successfully being used by Telecom as well as exploratory PCC systems that are being investigated are briefly reviewed.<<ETX>>","PeriodicalId":272740,"journal":{"name":"Conference Proceedings., Eleventh International Telecommunications Energy Conference","volume":"138 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":"123277426","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.1989.88323
H. Kiehne
The authors consider what is to be done with used batteries that contain hazardous substances. It is emphasized that an international standard on types of cells and batteries that have to be returned to the manufacturer is necessary for batteries that are used by the common public. The International Recycling Symbol ISO 7000-1135 has been proposed for the marking; a coming EEC directive will specify the marking of certain batteries with this symbol. In parallel, IEC-TC 21, Secondary Batteries, and IEC-TC 35, Primary Batteries, are preparing standards for a method of marking of certain batteries with the ISO symbol. In some European countries the battery industry has already started to mark such batteries as starter batteries, sealed nickel-cadmium batteries, small portable valve-regulated lead-acid batteries, and mercury button cells. In addition, regulations will be prepared to mark devices and equipment containing built-in batteries.<>
{"title":"What is to do with used batteries within telecommunications services?","authors":"H. Kiehne","doi":"10.1109/INTLEC.1989.88323","DOIUrl":"https://doi.org/10.1109/INTLEC.1989.88323","url":null,"abstract":"The authors consider what is to be done with used batteries that contain hazardous substances. It is emphasized that an international standard on types of cells and batteries that have to be returned to the manufacturer is necessary for batteries that are used by the common public. The International Recycling Symbol ISO 7000-1135 has been proposed for the marking; a coming EEC directive will specify the marking of certain batteries with this symbol. In parallel, IEC-TC 21, Secondary Batteries, and IEC-TC 35, Primary Batteries, are preparing standards for a method of marking of certain batteries with the ISO symbol. In some European countries the battery industry has already started to mark such batteries as starter batteries, sealed nickel-cadmium batteries, small portable valve-regulated lead-acid batteries, and mercury button cells. In addition, regulations will be prepared to mark devices and equipment containing built-in batteries.<<ETX>>","PeriodicalId":272740,"journal":{"name":"Conference Proceedings., Eleventh International Telecommunications Energy Conference","volume":"64 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":"131808862","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.1989.88254
M. Robins
Mitsubishi Electric UK Limited and British Telecom Power & Building Services have combined their local resources to develop an integrated and highly flexible system using programmable logic controllers and computers using an interactive graphic package (MING). The main feature of the system is that either a local engineer or an engineer at a remote maintenance location can interrogate the complete standby installation, including each generator control system and the synchronizing system, to check all fault status and availability of equipment data. A major factor is that this operation can be carried out via modem over the Public Service Telephone Network, thereby allowing one centralized maintenance controller to monitor and interrogate a number of different installations in his geographical domain. Any faults or error conditions can be logged locally if required, so that when a scheduled maintenance visit takes place the previous faults can be investigated and acted upon. By operating in a real-time environment, this allows the central maintenance controller to initiate any urgent remedial activity should he find that an alarm condition at one of his sites demand immediate attention. In addition to the access by local and remote operators, each site has a similar configuration of programmable controllers.<>
{"title":"Standby power systems, remote control and monitoring","authors":"M. Robins","doi":"10.1109/INTLEC.1989.88254","DOIUrl":"https://doi.org/10.1109/INTLEC.1989.88254","url":null,"abstract":"Mitsubishi Electric UK Limited and British Telecom Power & Building Services have combined their local resources to develop an integrated and highly flexible system using programmable logic controllers and computers using an interactive graphic package (MING). The main feature of the system is that either a local engineer or an engineer at a remote maintenance location can interrogate the complete standby installation, including each generator control system and the synchronizing system, to check all fault status and availability of equipment data. A major factor is that this operation can be carried out via modem over the Public Service Telephone Network, thereby allowing one centralized maintenance controller to monitor and interrogate a number of different installations in his geographical domain. Any faults or error conditions can be logged locally if required, so that when a scheduled maintenance visit takes place the previous faults can be investigated and acted upon. By operating in a real-time environment, this allows the central maintenance controller to initiate any urgent remedial activity should he find that an alarm condition at one of his sites demand immediate attention. In addition to the access by local and remote operators, each site has a similar configuration of programmable controllers.<<ETX>>","PeriodicalId":272740,"journal":{"name":"Conference Proceedings., Eleventh International Telecommunications Energy Conference","volume":"14 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":"124701837","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.1989.88349
D. McMenamin
There has been much interest expressed regarding the reduction of the expense associated with the maintenance of telecommunications power plants. Technological advances have drastically reduced the numbers of technicians in the central office. Since the smaller switches used less power, smaller plants were needed, and dedicated power room technicians were the first to be eliminated when the budget for technicians was cut. The switch technician must now maintain the power plant. In similar fashion, when the office workload is high, power maintenance is a lower priority and is usually postponed, sometimes indefinitely. Frequently, this leads to catastrophic failures. It is argued that the cost of maintenance plus the cost of neglect must be considered. Modern equipment and tooling is capable of reducing the risk for the power plant. The author explores products and techniques which may reduce the need (or frequency) for periodic maintenance, while reducing the risk of plant failure. Techniques relating to battery maintenance, battery stands, and engine sets are examined.<>
{"title":"Power maintenance reduction-a mixed blessing","authors":"D. McMenamin","doi":"10.1109/INTLEC.1989.88349","DOIUrl":"https://doi.org/10.1109/INTLEC.1989.88349","url":null,"abstract":"There has been much interest expressed regarding the reduction of the expense associated with the maintenance of telecommunications power plants. Technological advances have drastically reduced the numbers of technicians in the central office. Since the smaller switches used less power, smaller plants were needed, and dedicated power room technicians were the first to be eliminated when the budget for technicians was cut. The switch technician must now maintain the power plant. In similar fashion, when the office workload is high, power maintenance is a lower priority and is usually postponed, sometimes indefinitely. Frequently, this leads to catastrophic failures. It is argued that the cost of maintenance plus the cost of neglect must be considered. Modern equipment and tooling is capable of reducing the risk for the power plant. The author explores products and techniques which may reduce the need (or frequency) for periodic maintenance, while reducing the risk of plant failure. Techniques relating to battery maintenance, battery stands, and engine sets are examined.<<ETX>>","PeriodicalId":272740,"journal":{"name":"Conference Proceedings., Eleventh International Telecommunications Energy Conference","volume":"35 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":"127602383","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.1989.88294
E. Lombardini, G. Cariani
After describing the fundamental concepts of electromagnetic compatibility (EMC) and nuclear electromagnetic pulses (NEMP), the authors report on the engineering, construction, and test data for a NEMP-protected diesel power plant used as a power source for TLC systems. The test results indicate that the average attenuation (47 dB) of the electric field obtained from the CW test for f=100 MHz, the frequency below which 99.9% of the NEMP energy is concentrated, involves an average interfering signal level of 223 V/m, which cannot compromise the proper operation of the most sensitive electronic circuits since they are housed in the innermost zones. The attenuation of electric field in the NEMP susceptibility test varies markedly according to the geometric configuration of the gen set.<>
{"title":"EMC/NEMP technology from military applications to telecommunications","authors":"E. Lombardini, G. Cariani","doi":"10.1109/INTLEC.1989.88294","DOIUrl":"https://doi.org/10.1109/INTLEC.1989.88294","url":null,"abstract":"After describing the fundamental concepts of electromagnetic compatibility (EMC) and nuclear electromagnetic pulses (NEMP), the authors report on the engineering, construction, and test data for a NEMP-protected diesel power plant used as a power source for TLC systems. The test results indicate that the average attenuation (47 dB) of the electric field obtained from the CW test for f=100 MHz, the frequency below which 99.9% of the NEMP energy is concentrated, involves an average interfering signal level of 223 V/m, which cannot compromise the proper operation of the most sensitive electronic circuits since they are housed in the innermost zones. The attenuation of electric field in the NEMP susceptibility test varies markedly according to the geometric configuration of the gen set.<<ETX>>","PeriodicalId":272740,"journal":{"name":"Conference Proceedings., Eleventh International Telecommunications Energy Conference","volume":"20 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":"133877783","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.1989.88337
A. Mclennan
Some of the problems that can be caused by high crest factor (HCF) in UPSs (uninterruptible power supply systems) are outlined. It is noted that the effect of a high crest factor load on a UPS will depend on the technique used to generate the UPS output voltage. Ways to avoid problems with HCF are discussed, including load balancing, the use of a fully rated neutral conductor, the measurement of voltages at the UPS and the load, the correct rating of the UPS, and the use of a third-harmonic filter.<>
{"title":"High crest factor loads on UPS systems","authors":"A. Mclennan","doi":"10.1109/INTLEC.1989.88337","DOIUrl":"https://doi.org/10.1109/INTLEC.1989.88337","url":null,"abstract":"Some of the problems that can be caused by high crest factor (HCF) in UPSs (uninterruptible power supply systems) are outlined. It is noted that the effect of a high crest factor load on a UPS will depend on the technique used to generate the UPS output voltage. Ways to avoid problems with HCF are discussed, including load balancing, the use of a fully rated neutral conductor, the measurement of voltages at the UPS and the load, the correct rating of the UPS, and the use of a third-harmonic filter.<<ETX>>","PeriodicalId":272740,"journal":{"name":"Conference Proceedings., Eleventh International Telecommunications Energy Conference","volume":"25 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":"133919235","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.1989.88293
B. Gray
The author explains some of the factors which need to be considered by designers, specifiers, and buyers when choosing battery back-up systems for telecommunication equipment. An awareness of the battery requirements will ensure the maximum predictable lifetime when using a reliable, maintenance-free battery. These factors will help the designer obtain the best, safest, and most cost-effective battery possible. Particular consideration is given to the choice of rectifier, power calculations, and space savings.<>
{"title":"Factors to be considered when choosing a back up battery for telecommunications","authors":"B. Gray","doi":"10.1109/INTLEC.1989.88293","DOIUrl":"https://doi.org/10.1109/INTLEC.1989.88293","url":null,"abstract":"The author explains some of the factors which need to be considered by designers, specifiers, and buyers when choosing battery back-up systems for telecommunication equipment. An awareness of the battery requirements will ensure the maximum predictable lifetime when using a reliable, maintenance-free battery. These factors will help the designer obtain the best, safest, and most cost-effective battery possible. Particular consideration is given to the choice of rectifier, power calculations, and space savings.<<ETX>>","PeriodicalId":272740,"journal":{"name":"Conference Proceedings., Eleventh International Telecommunications Energy Conference","volume":"8 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":"130944329","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.1989.88306
G. I. Kenney, M.W.G. Whittall, M. Larocque
The authors report on the planning and implementation of a solar refit program on part of the Panaftel microwave system in West Africa, linking Senegal, Mali, Burkina Faso, Niger, and Benin. It is concluded that in spite of the high initial capital cost, conversion from fuel-dependent power systems to photovoltaic (PV) systems on major microwave routes can be economically sound. The main saving is in fuel cost. Although routine and emergency maintenance will in all probability be reduced, overall maintenance expenditures may not be very different between fuel-dependent systems and PV systems. This is due to the high cost of periodic replacement of aging batteries that is necessary. The effect of conversion on telecommunication system availability is positive, although it was not possible to quantify this factor due to other improvements being introduced during the same time frame. A simplification of maintenance power requirements is foreseeable with the introduction of PV systems.<>
{"title":"Refitting a major microwave radio system with photovoltaic power supplies","authors":"G. I. Kenney, M.W.G. Whittall, M. Larocque","doi":"10.1109/INTLEC.1989.88306","DOIUrl":"https://doi.org/10.1109/INTLEC.1989.88306","url":null,"abstract":"The authors report on the planning and implementation of a solar refit program on part of the Panaftel microwave system in West Africa, linking Senegal, Mali, Burkina Faso, Niger, and Benin. It is concluded that in spite of the high initial capital cost, conversion from fuel-dependent power systems to photovoltaic (PV) systems on major microwave routes can be economically sound. The main saving is in fuel cost. Although routine and emergency maintenance will in all probability be reduced, overall maintenance expenditures may not be very different between fuel-dependent systems and PV systems. This is due to the high cost of periodic replacement of aging batteries that is necessary. The effect of conversion on telecommunication system availability is positive, although it was not possible to quantify this factor due to other improvements being introduced during the same time frame. A simplification of maintenance power requirements is foreseeable with the introduction of PV systems.<<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":"132912438","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.1989.88343
B. Assow
It is demonstrated that it is possible to manufacture a very compact high-power switch-mode power supply based on the flyback technique using standard components, with no sacrifice in performance and operation at 80 kHz. A superior flyback converter can be designed on the basis of the following criteria: (1) choosing a pulse ratio to optimize the switching transistor/diode; (2) assuring low leakage inductance in the transformer and a way of taking care of the energy stored in it; (3) choosing a turns ratio in the transformer that will ensure a low leakage inductance and low output ripple; (4) choosing the airgap and number of turns depending on transformer and output voltage; (5) always having one higher-frequency secondary winding (tightly coupled to the primary) and one 'lower frequency' winding for the main part of the current; and (6) tuning the leakage inductance to maximum efficiency.<>
{"title":"A 400 W flyback converter","authors":"B. Assow","doi":"10.1109/INTLEC.1989.88343","DOIUrl":"https://doi.org/10.1109/INTLEC.1989.88343","url":null,"abstract":"It is demonstrated that it is possible to manufacture a very compact high-power switch-mode power supply based on the flyback technique using standard components, with no sacrifice in performance and operation at 80 kHz. A superior flyback converter can be designed on the basis of the following criteria: (1) choosing a pulse ratio to optimize the switching transistor/diode; (2) assuring low leakage inductance in the transformer and a way of taking care of the energy stored in it; (3) choosing a turns ratio in the transformer that will ensure a low leakage inductance and low output ripple; (4) choosing the airgap and number of turns depending on transformer and output voltage; (5) always having one higher-frequency secondary winding (tightly coupled to the primary) and one 'lower frequency' winding for the main part of the current; and (6) tuning the leakage inductance to maximum efficiency.<<ETX>>","PeriodicalId":272740,"journal":{"name":"Conference Proceedings., Eleventh International Telecommunications Energy Conference","volume":"14 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":"132849826","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.1989.88330
S. Muroyama, T. Aoki, K. Yotsumoto
The authors describe a novel control method for a high-frequency link inverter using cycloconverter techniques and discuss its output voltage characteristics. In this method, the cycloconverter converts a high-frequency voltage to a low-frequency voltage by operating in three modes: positive rectifying mode, negative rectifying mode, and free-wheeling mode. Pulse-width-modulation control is performed at the cycloconverter. Numerical analysis and experiments show that the output voltage can be proportionally controlled by a reference voltage and that the output harmonics can be decreased to a sufficiently low level. A surge reduction circuit is presented for the inverter. This circuit can effectively reduce the switching surge. A conversion efficiency of over 90% is obtained with an output power of 1 kW.<>
{"title":"A control method for a high frequency link inverter using cycloconverter techniques","authors":"S. Muroyama, T. Aoki, K. Yotsumoto","doi":"10.1109/INTLEC.1989.88330","DOIUrl":"https://doi.org/10.1109/INTLEC.1989.88330","url":null,"abstract":"The authors describe a novel control method for a high-frequency link inverter using cycloconverter techniques and discuss its output voltage characteristics. In this method, the cycloconverter converts a high-frequency voltage to a low-frequency voltage by operating in three modes: positive rectifying mode, negative rectifying mode, and free-wheeling mode. Pulse-width-modulation control is performed at the cycloconverter. Numerical analysis and experiments show that the output voltage can be proportionally controlled by a reference voltage and that the output harmonics can be decreased to a sufficiently low level. A surge reduction circuit is presented for the inverter. This circuit can effectively reduce the switching surge. A conversion efficiency of over 90% is obtained with an output power of 1 kW.<<ETX>>","PeriodicalId":272740,"journal":{"name":"Conference Proceedings., Eleventh International Telecommunications Energy Conference","volume":"42 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":"123813546","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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