Pub Date : 1990-10-21DOI: 10.1109/INTLEC.1990.171305
B. Ulrich
Availability of a modern telecommunications system as a function of correct operation of its power supply, heat transfer, and cooling is addressed. Two projects were carried out: one was a powered and cooled cabinet for outdoor applications and the second was a liquid-cooled MS 2000-300A/C power supply system with an energy saving heat transfer and cooling system. The infrastructure supplied with the cabinet consists of an uninterruptible power supply system, cooling system and other equipment necessary for operation in a telecommunications environment. Liquid cooling of the second project is based on a consistent heat evacuation from heat dissipating devices through a low thermal resistance, primarily metallic pad (eg, advanced PCBs) on the device and module level, to the liquid thermal bus on the rack, room, and building level. The concept of the two projects and the results of the operational test are presented.<>
{"title":"Electronic packaging for indoor and outdoor applications-the economic aspects of two pilot projects","authors":"B. Ulrich","doi":"10.1109/INTLEC.1990.171305","DOIUrl":"https://doi.org/10.1109/INTLEC.1990.171305","url":null,"abstract":"Availability of a modern telecommunications system as a function of correct operation of its power supply, heat transfer, and cooling is addressed. Two projects were carried out: one was a powered and cooled cabinet for outdoor applications and the second was a liquid-cooled MS 2000-300A/C power supply system with an energy saving heat transfer and cooling system. The infrastructure supplied with the cabinet consists of an uninterruptible power supply system, cooling system and other equipment necessary for operation in a telecommunications environment. Liquid cooling of the second project is based on a consistent heat evacuation from heat dissipating devices through a low thermal resistance, primarily metallic pad (eg, advanced PCBs) on the device and module level, to the liquid thermal bus on the rack, room, and building level. The concept of the two projects and the results of the operational test are presented.<<ETX>>","PeriodicalId":264940,"journal":{"name":"12th International Conference on Telecommunications Energy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1990-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129202922","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 : 1990-10-21DOI: 10.1109/INTLEC.1990.171260
A. Kislovski
A measuring system of output characteristics of photovoltaic panels is described. This system is implemented as a maximum power point monitor (MPPM) that quasi-instantaneously determines the photovoltaic generator. This information is then used to compute the overall efficiency of the plant defined as the ratio of its output power to the maximum available photovoltaic power. In this way the performance of the maximum power point tracker and of the entire plant can be precisely evaluated under widely varying operating conditions. The MPPM is an efficient development and control tool, particularly useful when different maximum power point tracking strategies are being compared. It is intended primarily for battery chargers and, generally, for DC-DC power converters but can easily be adapted for use with inverters.<>
{"title":"Maximum power point monitor","authors":"A. Kislovski","doi":"10.1109/INTLEC.1990.171260","DOIUrl":"https://doi.org/10.1109/INTLEC.1990.171260","url":null,"abstract":"A measuring system of output characteristics of photovoltaic panels is described. This system is implemented as a maximum power point monitor (MPPM) that quasi-instantaneously determines the photovoltaic generator. This information is then used to compute the overall efficiency of the plant defined as the ratio of its output power to the maximum available photovoltaic power. In this way the performance of the maximum power point tracker and of the entire plant can be precisely evaluated under widely varying operating conditions. The MPPM is an efficient development and control tool, particularly useful when different maximum power point tracking strategies are being compared. It is intended primarily for battery chargers and, generally, for DC-DC power converters but can easily be adapted for use with inverters.<<ETX>>","PeriodicalId":264940,"journal":{"name":"12th International Conference on Telecommunications Energy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1990-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122610681","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 : 1990-10-21DOI: 10.1109/INTLEC.1990.171283
K. Sakamoto, M. Nagao, T. Katayama
This system consists of the following equipment: diesel engine-generators (800 kW*2), an absorption chiller, and a system controller. Electric power is generated from 8 AM to 10 PM. The two diesel engine-generators operate alternately for one week. The reduction in energy cost from February 1989 to January 1990 was approximately 36 million yen. The cogeneration system generated 3700 MWh (the total energy used in the Okayama Network Center was 7000 MWh) and reduced contract power by 900 kW (1700 kW to 800 kW) during this period. The energy efficiency was approximately 65% (generation efficiency was 40%, heat recovery efficiency was 25%).<>
{"title":"Cogeneration systems for telecommunication power plants","authors":"K. Sakamoto, M. Nagao, T. Katayama","doi":"10.1109/INTLEC.1990.171283","DOIUrl":"https://doi.org/10.1109/INTLEC.1990.171283","url":null,"abstract":"This system consists of the following equipment: diesel engine-generators (800 kW*2), an absorption chiller, and a system controller. Electric power is generated from 8 AM to 10 PM. The two diesel engine-generators operate alternately for one week. The reduction in energy cost from February 1989 to January 1990 was approximately 36 million yen. The cogeneration system generated 3700 MWh (the total energy used in the Okayama Network Center was 7000 MWh) and reduced contract power by 900 kW (1700 kW to 800 kW) during this period. The energy efficiency was approximately 65% (generation efficiency was 40%, heat recovery efficiency was 25%).<<ETX>>","PeriodicalId":264940,"journal":{"name":"12th International Conference on Telecommunications Energy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1990-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115185497","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 : 1990-10-21DOI: 10.1109/INTLEC.1990.171311
E. Rhyne, R. Bennett
A method is proposed for producing precise single or multi-frequency tones for telephone office ringing generators, tone generators, and general purpose inverters, by using microprocessors and digital technology. The system comprises microcontrollers, counters, timers, random access memory (RAM), analog to digital converters (A/D), and digital to analog converters (D/A), which are combined to produce tone signals. These signals are then amplified to produce the required ringing or tone power. The microcontroller is programmed with a mathematical equation to derive timing and voltage levels for the output signal. This equation is converted to digital words that are passed to the data portion of RAM and is converted to a digital word that sets a timer controlling the address portion to RAM. The RAM output is converted to an analog signal by the D/A converter. This signal is used by a power amplifier to condition the signal for use on the telephone lines. By using a microcontroller, the terms of the equation (ie frequencies and the voltage levels of each frequency independently) are input as variables, thus giving the user complete control of the output signal.<>
{"title":"A novel use for microprocessors in designing single and multi-tone generators, ringing generators and inverters","authors":"E. Rhyne, R. Bennett","doi":"10.1109/INTLEC.1990.171311","DOIUrl":"https://doi.org/10.1109/INTLEC.1990.171311","url":null,"abstract":"A method is proposed for producing precise single or multi-frequency tones for telephone office ringing generators, tone generators, and general purpose inverters, by using microprocessors and digital technology. The system comprises microcontrollers, counters, timers, random access memory (RAM), analog to digital converters (A/D), and digital to analog converters (D/A), which are combined to produce tone signals. These signals are then amplified to produce the required ringing or tone power. The microcontroller is programmed with a mathematical equation to derive timing and voltage levels for the output signal. This equation is converted to digital words that are passed to the data portion of RAM and is converted to a digital word that sets a timer controlling the address portion to RAM. The RAM output is converted to an analog signal by the D/A converter. This signal is used by a power amplifier to condition the signal for use on the telephone lines. By using a microcontroller, the terms of the equation (ie frequencies and the voltage levels of each frequency independently) are input as variables, thus giving the user complete control of the output signal.<<ETX>>","PeriodicalId":264940,"journal":{"name":"12th International Conference on Telecommunications Energy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1990-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115724527","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 : 1990-10-21DOI: 10.1109/INTLEC.1990.171294
G. Marchetti, M. Piccolo
In order to develop renewable energy sources technology in power supply plants, it is necessary to provide designers with tools capable of recognizing at short notice any areas of convenience in its utilization, either as a stand-alone or as a hybrid (with generator back-up) project. Typical renewable sources considered are solar and wind energy, but the results are applicable to any other energy source. The block diagram of the plant includes renewable generator(s), storage battery, and standby diesel engine generator. At first, the authors developed an analysis based on a mathematical model that included only one renewable random source. This model related environmental statistical factors to the sizing parameters and consequently to the costs of each block. However, since the sizing is not univocally defined, the model takes the battery autonomy as 'variable' and executes on it an optimization process finalized to minimum overall cost. In conclusion, the resulting output gives either the optimized sizing parameters or the costs of each block. A step-by-step optimization procedure is described including: annual cost vs battery autonomy function consideration; mathematical approach to the environmental influence; sizing criteria of the renewable generator; the database utilized and its analysis; model algorithms; comparison between experimental and theoretical results; and the two renewable generators model.<>
{"title":"Mathematical models for the construction of a renewable energy hybrid plant","authors":"G. Marchetti, M. Piccolo","doi":"10.1109/INTLEC.1990.171294","DOIUrl":"https://doi.org/10.1109/INTLEC.1990.171294","url":null,"abstract":"In order to develop renewable energy sources technology in power supply plants, it is necessary to provide designers with tools capable of recognizing at short notice any areas of convenience in its utilization, either as a stand-alone or as a hybrid (with generator back-up) project. Typical renewable sources considered are solar and wind energy, but the results are applicable to any other energy source. The block diagram of the plant includes renewable generator(s), storage battery, and standby diesel engine generator. At first, the authors developed an analysis based on a mathematical model that included only one renewable random source. This model related environmental statistical factors to the sizing parameters and consequently to the costs of each block. However, since the sizing is not univocally defined, the model takes the battery autonomy as 'variable' and executes on it an optimization process finalized to minimum overall cost. In conclusion, the resulting output gives either the optimized sizing parameters or the costs of each block. A step-by-step optimization procedure is described including: annual cost vs battery autonomy function consideration; mathematical approach to the environmental influence; sizing criteria of the renewable generator; the database utilized and its analysis; model algorithms; comparison between experimental and theoretical results; and the two renewable generators model.<<ETX>>","PeriodicalId":264940,"journal":{"name":"12th International Conference on Telecommunications Energy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1990-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126851541","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 : 1990-10-21DOI: 10.1109/INTLEC.1990.171279
H. Yamashita
A decentralized power system for an AC power system and a DC power system has been developed. In this system, the uninterruptible power supply (UPS) system is installed in telecommunications rooms, and is aimed at peripheral equipment in switching systems. This UPS system consists of 1 kVA add-on type inverter units, and has a maximum capacity of 5 kVA through parallel operation of 5 units. The inverter unit operates at a switching frequency of 25 kHz and weighs 14 kg per unit. The UPS system can supply the rated capacity of power even for equipment employing a rectifier circuit and a capacitor input filter. In addition, it can operate in both off-line mode and on-line mode. The UPS system can supply uninterruptible AC power even in the off-line mode. The author describes the configuration and the operation of the UPS system, and discusses the techniques for the off-line mode and high crest factor loads.<>
{"title":"Uninterruptible power supply systems in NTT","authors":"H. Yamashita","doi":"10.1109/INTLEC.1990.171279","DOIUrl":"https://doi.org/10.1109/INTLEC.1990.171279","url":null,"abstract":"A decentralized power system for an AC power system and a DC power system has been developed. In this system, the uninterruptible power supply (UPS) system is installed in telecommunications rooms, and is aimed at peripheral equipment in switching systems. This UPS system consists of 1 kVA add-on type inverter units, and has a maximum capacity of 5 kVA through parallel operation of 5 units. The inverter unit operates at a switching frequency of 25 kHz and weighs 14 kg per unit. The UPS system can supply the rated capacity of power even for equipment employing a rectifier circuit and a capacitor input filter. In addition, it can operate in both off-line mode and on-line mode. The UPS system can supply uninterruptible AC power even in the off-line mode. The author describes the configuration and the operation of the UPS system, and discusses the techniques for the off-line mode and high crest factor loads.<<ETX>>","PeriodicalId":264940,"journal":{"name":"12th International Conference on Telecommunications Energy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1990-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123169128","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 : 1990-10-21DOI: 10.1109/INTLEC.1990.171282
J. White
In the early 1980s British Telecom embarked upon a program to introduce small packaged automatic standby AC power plant at small rural telephone exchanges. This development extended the operational reserve from 24 hours to 10 days. The background to the design and development of a new room sealed engine alternator set using a balanced flue arrangement is described. The balanced flue unit is ventilated independently of the environment in which it is sited, so that it is no longer necessary to have separate power rooms. Cooling and aspiration air are drawn through louvers from outside the building, through an acoustic pod and into the acoustically treated engine alternator cubicle. The air is then circulated around the engine set and then deposited with the exhaust out through the same acoustic pod and louvers to atmosphere. Initially the sets are rated between 6 kVA and 20 kVA for single and three-phase applications.<>
{"title":"Development and introduction of the room sealed packaged engine alternator set","authors":"J. White","doi":"10.1109/INTLEC.1990.171282","DOIUrl":"https://doi.org/10.1109/INTLEC.1990.171282","url":null,"abstract":"In the early 1980s British Telecom embarked upon a program to introduce small packaged automatic standby AC power plant at small rural telephone exchanges. This development extended the operational reserve from 24 hours to 10 days. The background to the design and development of a new room sealed engine alternator set using a balanced flue arrangement is described. The balanced flue unit is ventilated independently of the environment in which it is sited, so that it is no longer necessary to have separate power rooms. Cooling and aspiration air are drawn through louvers from outside the building, through an acoustic pod and into the acoustically treated engine alternator cubicle. The air is then circulated around the engine set and then deposited with the exhaust out through the same acoustic pod and louvers to atmosphere. Initially the sets are rated between 6 kVA and 20 kVA for single and three-phase applications.<<ETX>>","PeriodicalId":264940,"journal":{"name":"12th International Conference on Telecommunications Energy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1990-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125274871","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 : 1990-10-21DOI: 10.1109/INTLEC.1990.171229
T. Chandler
Research and engineering for a new development in small emergency power systems are described. Insight is provided into the problems and solutions of providing clean stable power for small telephone and computer systems from small emergency generators. While large telephone systems have carefully engineered emergency power systems, the small user has had very few choices in powering a PABX or key system in the event of a long-term power outage. An alternative to very large battery back-up systems is discussed. This is an interruptible transfer switch that provides an interface to a small inexpensive generator.<>
{"title":"A new development in emergency power for small to mid sized CPE telephone systems","authors":"T. Chandler","doi":"10.1109/INTLEC.1990.171229","DOIUrl":"https://doi.org/10.1109/INTLEC.1990.171229","url":null,"abstract":"Research and engineering for a new development in small emergency power systems are described. Insight is provided into the problems and solutions of providing clean stable power for small telephone and computer systems from small emergency generators. While large telephone systems have carefully engineered emergency power systems, the small user has had very few choices in powering a PABX or key system in the event of a long-term power outage. An alternative to very large battery back-up systems is discussed. This is an interruptible transfer switch that provides an interface to a small inexpensive generator.<<ETX>>","PeriodicalId":264940,"journal":{"name":"12th International Conference on Telecommunications Energy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1990-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114679130","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 : 1990-10-21DOI: 10.1109/INTLEC.1990.171242
Y. Nagai, K. Ozaki
Lead-acid batteries used in the power supplied for communication and information-processing equipment are considered. In the event of commercial power failures, such batteries are useful in providing a stable supply of power to the load, and providing for uninterruptible power. Recently valve regulated sealed lead-acid batteries have come to be used often in such applications, but there are some attendant difficulties to be considered. The authors present their views, based upon experimental data about how to deal with the design of battery boxes to give the batteries long life, charging voltage control, and temperature rises due to ripple currents. Additionally, when many batteries are connected in parallel, the individual batteries in each string tend to develop imbalances in characteristics and service life, and how these should be dealt with is examined.<>
{"title":"Problems and solutions pertaining to the use of lead-acid batteries used in power supplies for electronic equipment","authors":"Y. Nagai, K. Ozaki","doi":"10.1109/INTLEC.1990.171242","DOIUrl":"https://doi.org/10.1109/INTLEC.1990.171242","url":null,"abstract":"Lead-acid batteries used in the power supplied for communication and information-processing equipment are considered. In the event of commercial power failures, such batteries are useful in providing a stable supply of power to the load, and providing for uninterruptible power. Recently valve regulated sealed lead-acid batteries have come to be used often in such applications, but there are some attendant difficulties to be considered. The authors present their views, based upon experimental data about how to deal with the design of battery boxes to give the batteries long life, charging voltage control, and temperature rises due to ripple currents. Additionally, when many batteries are connected in parallel, the individual batteries in each string tend to develop imbalances in characteristics and service life, and how these should be dealt with is examined.<<ETX>>","PeriodicalId":264940,"journal":{"name":"12th International Conference on Telecommunications Energy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1990-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114420335","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 : 1990-10-21DOI: 10.1109/INTLEC.1990.171273
J. Feret
One key alternate energy area under development within the Westinghouse Electric Corporation is the air-cooled phosphoric acid fuel cell (PAFC). Air-cooling was selected because of its inherent reliability and maintainability features. These features, along with the modular power plant approach, are expected to make this technology attractive to both commercial and utility customers. After over a decade of development, Westinghouse is nearing completion of its PAFC technology development program, with up to 3 MW on-site demonstrations. Operational principles of fuel cells, overview of the PAFC program, Westinghouse prototype plant design, cell technology, small and large stack test results, and the commercialization program are outlined.<>
{"title":"An overview of the Westinghouse air-cooled phosphoric acid fuel cell program","authors":"J. Feret","doi":"10.1109/INTLEC.1990.171273","DOIUrl":"https://doi.org/10.1109/INTLEC.1990.171273","url":null,"abstract":"One key alternate energy area under development within the Westinghouse Electric Corporation is the air-cooled phosphoric acid fuel cell (PAFC). Air-cooling was selected because of its inherent reliability and maintainability features. These features, along with the modular power plant approach, are expected to make this technology attractive to both commercial and utility customers. After over a decade of development, Westinghouse is nearing completion of its PAFC technology development program, with up to 3 MW on-site demonstrations. Operational principles of fuel cells, overview of the PAFC program, Westinghouse prototype plant design, cell technology, small and large stack test results, and the commercialization program are outlined.<<ETX>>","PeriodicalId":264940,"journal":{"name":"12th International Conference on Telecommunications Energy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1990-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124066935","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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