Pub Date : 1987-06-14DOI: 10.1109/INTLEC.1987.4794619
K. Ohshima, M. Nakao, Hirosi Jitukawa
When the compressor of a packaged air-conditioner for cooling a containerized station stops operating, the relative humidity of the room exceeds the upper limit of the specified range. The high relative humidity phenomenon is caused by water forming on the cooling coil of the air-conditioner. This water condenses, while the compressor is running, and is vaporized by the fan airflow which continuously operates, even after the compressor stops operating. As a result of this the water is not expelled to the outside but remains in the room, and the relative humidity increases. Several experiments are conducted to find a way of reducing the relative humidity in containerized stations. One way involves reducing the draft air volume, which contains a high level of moisture. Experiments and field tests indicated that the most effective method for maintaining the specified temperature range and relative humidity in a room, is to control the compressor by the room air temperature and the room fan by the relative humidity when the compressor stops operating.
{"title":"Humidity Control in a Containerized Station","authors":"K. Ohshima, M. Nakao, Hirosi Jitukawa","doi":"10.1109/INTLEC.1987.4794619","DOIUrl":"https://doi.org/10.1109/INTLEC.1987.4794619","url":null,"abstract":"When the compressor of a packaged air-conditioner for cooling a containerized station stops operating, the relative humidity of the room exceeds the upper limit of the specified range. The high relative humidity phenomenon is caused by water forming on the cooling coil of the air-conditioner. This water condenses, while the compressor is running, and is vaporized by the fan airflow which continuously operates, even after the compressor stops operating. As a result of this the water is not expelled to the outside but remains in the room, and the relative humidity increases. Several experiments are conducted to find a way of reducing the relative humidity in containerized stations. One way involves reducing the draft air volume, which contains a high level of moisture. Experiments and field tests indicated that the most effective method for maintaining the specified temperature range and relative humidity in a room, is to control the compressor by the room air temperature and the room fan by the relative humidity when the compressor stops operating.","PeriodicalId":129305,"journal":{"name":"INTELEC '87 - The Ninth International Telecommunications Energy Conference","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1987-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134234420","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 : 1987-06-14DOI: 10.1109/INTLEC.1987.4794626
K. Lundqvist
This paper deals with experience from comparative laboratory tests, carried out by Televerket - Swedish Telecommunications Administration - on different types of stationary lead-acid batteries for telecommunications applications. Examples are given on how experience has been used to increase quality and reliability in batteries. The test batteries have been kept under verified charge conditions for many years. Capacity tests have been carried out regularly. Water consumption, deviations in cell voltages etc have been checked during the test period. Differences between batteries, expected to be equivalent, have been found. Experience from the testing has also given valuable reference to batteries in service at telecommunication plants.
{"title":"Experience from Long-Term Laboratory Testing of Stationary Lead-Acid Batteries","authors":"K. Lundqvist","doi":"10.1109/INTLEC.1987.4794626","DOIUrl":"https://doi.org/10.1109/INTLEC.1987.4794626","url":null,"abstract":"This paper deals with experience from comparative laboratory tests, carried out by Televerket - Swedish Telecommunications Administration - on different types of stationary lead-acid batteries for telecommunications applications. Examples are given on how experience has been used to increase quality and reliability in batteries. The test batteries have been kept under verified charge conditions for many years. Capacity tests have been carried out regularly. Water consumption, deviations in cell voltages etc have been checked during the test period. Differences between batteries, expected to be equivalent, have been found. Experience from the testing has also given valuable reference to batteries in service at telecommunication plants.","PeriodicalId":129305,"journal":{"name":"INTELEC '87 - The Ninth International Telecommunications Energy Conference","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1987-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132595765","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 : 1987-06-14DOI: 10.1109/INTLEC.1987.4794635
T. Suntio
Methods used to evaluate reliability and availability performance of telecom power systems are described. The models are based on Markov chains in steady-state conditions assuming expotential distributions. The models and methods normally used have been developed further in order to obtain more numerical information on the effects of monitoring systems and operating practices of maintenance staff on power system reliability and availability performance. In addition, a telecom power system is analyzed, and results together with their dependence on various system parameters are discussed.
{"title":"Evaluation of Power Systems Availability using Simplified Methods based on Markov Chains","authors":"T. Suntio","doi":"10.1109/INTLEC.1987.4794635","DOIUrl":"https://doi.org/10.1109/INTLEC.1987.4794635","url":null,"abstract":"Methods used to evaluate reliability and availability performance of telecom power systems are described. The models are based on Markov chains in steady-state conditions assuming expotential distributions. The models and methods normally used have been developed further in order to obtain more numerical information on the effects of monitoring systems and operating practices of maintenance staff on power system reliability and availability performance. In addition, a telecom power system is analyzed, and results together with their dependence on various system parameters are discussed.","PeriodicalId":129305,"journal":{"name":"INTELEC '87 - The Ninth International Telecommunications Energy Conference","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1987-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115753893","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 : 1987-06-14DOI: 10.1109/INTLEC.1987.4794608
F. Barzegar, M. J. Model
This paper introduces a new ac Uninterruptible Power Supply (UPS) that has high efficiency, ac-input voltage regulation, and continuity of output power during any type of commercial ac-input power disturbance. These features are achieved in this UPS without the ac line-frequency energy storage components utilized in other UPSs to maintain output continuity during an ac-input power failure.
{"title":"A Novel AC Uninterruptible Power Supply","authors":"F. Barzegar, M. J. Model","doi":"10.1109/INTLEC.1987.4794608","DOIUrl":"https://doi.org/10.1109/INTLEC.1987.4794608","url":null,"abstract":"This paper introduces a new ac Uninterruptible Power Supply (UPS) that has high efficiency, ac-input voltage regulation, and continuity of output power during any type of commercial ac-input power disturbance. These features are achieved in this UPS without the ac line-frequency energy storage components utilized in other UPSs to maintain output continuity during an ac-input power failure.","PeriodicalId":129305,"journal":{"name":"INTELEC '87 - The Ninth International Telecommunications Energy Conference","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1987-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115303463","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 : 1987-06-14DOI: 10.1109/INTLEC.1987.4794523
J. Horzepa, M. E. Jacobs
This paper describes the impact of the rapidly evolving telecommunications network on power and powering arrangements, paying close attention to the confluence of telecommunications and computer systems. Fundamental features of powering strategies are addressed, including reserve energy systems, interconnect, thermal, and distributed architectures.
{"title":"Critical Issues in Powering Emerging Telecommunications Systems","authors":"J. Horzepa, M. E. Jacobs","doi":"10.1109/INTLEC.1987.4794523","DOIUrl":"https://doi.org/10.1109/INTLEC.1987.4794523","url":null,"abstract":"This paper describes the impact of the rapidly evolving telecommunications network on power and powering arrangements, paying close attention to the confluence of telecommunications and computer systems. Fundamental features of powering strategies are addressed, including reserve energy systems, interconnect, thermal, and distributed architectures.","PeriodicalId":129305,"journal":{"name":"INTELEC '87 - The Ninth International Telecommunications Energy Conference","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1987-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123428986","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 : 1987-06-14DOI: 10.1109/INTLEC.1987.4794542
T. Matsushima, M. Ichimura, T. Take
Lead-acid batteries used in telecommunications systems as a standby power sources play an important role in providing power in the event of commercial power failures. However, these batteries require numerous inspections and a great deal of manpower to maintain them. Therefore, reduction of labor involved in those maintenance has been requested. Sealed lead-acid batteries with a large capacity and a long life have been developed for telecommunications applications. They are safe and easily maintained. They have a maximum capacity of 3,000 Ah and are designed to have a life of over 10 years. Parameters such as plate thickness and electrolyte specific gravity were determined to attain the specified performance and life. Adhesives and rubber valves are made of reliable materials. Flame-retardant resin is applied to the battery container. Performance tests in laboratory and in telephone offices have confirmed that the sealed lead-acid batteries exhibit satisfactory characteristics and are sufficiently suited to telecommunications applications.
{"title":"Large-Capacity and Long-Life Sealed Lead-Acid Batteries for Telecommunications Systems","authors":"T. Matsushima, M. Ichimura, T. Take","doi":"10.1109/INTLEC.1987.4794542","DOIUrl":"https://doi.org/10.1109/INTLEC.1987.4794542","url":null,"abstract":"Lead-acid batteries used in telecommunications systems as a standby power sources play an important role in providing power in the event of commercial power failures. However, these batteries require numerous inspections and a great deal of manpower to maintain them. Therefore, reduction of labor involved in those maintenance has been requested. Sealed lead-acid batteries with a large capacity and a long life have been developed for telecommunications applications. They are safe and easily maintained. They have a maximum capacity of 3,000 Ah and are designed to have a life of over 10 years. Parameters such as plate thickness and electrolyte specific gravity were determined to attain the specified performance and life. Adhesives and rubber valves are made of reliable materials. Flame-retardant resin is applied to the battery container. Performance tests in laboratory and in telephone offices have confirmed that the sealed lead-acid batteries exhibit satisfactory characteristics and are sufficiently suited to telecommunications applications.","PeriodicalId":129305,"journal":{"name":"INTELEC '87 - The Ninth International Telecommunications Energy Conference","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1987-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123777062","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 : 1987-06-14DOI: 10.1109/INTLEC.1987.4794586
N. Thuan
To cater for increasingly sophisticated and discerning major businesses and corporations, modern office buildings have become more complex and their many services integrated. Integrated Building Services (IBS) can be defined generally as an array of facilities and services (sub-systems) which are provided for an office complex, a telecommunications centre, a data processing centre etc. and which are connected to, controlled, monitored and managed by a computerised system. In the last ten years, Telecom Australia has provided and installed several computer controlled building Automation systems for a number of large telecommunications centres in Australia. The systems are given the name of Local Monitoring and Control Systems (LMCS) and provide primary control and monitoring services in a localised area. The basic purpose of the LMCS is to monitor and control air conditioning systems, power supply and distribution including emergency generating systems, fire detection, security and other systems in the building complex. Telecom Australia has taken steps to meet the challenge of the new trend in this field and is particularly interested in the design of and innovation in intelligent buildings. A system specification to serve as functional briefing for building developers has been developed for use in deliberations on requirements for Telecom Australia's proposed corporate Head Office complex in Melbourne and other major office accommodation complexes.
{"title":"Integrated Building Services","authors":"N. Thuan","doi":"10.1109/INTLEC.1987.4794586","DOIUrl":"https://doi.org/10.1109/INTLEC.1987.4794586","url":null,"abstract":"To cater for increasingly sophisticated and discerning major businesses and corporations, modern office buildings have become more complex and their many services integrated. Integrated Building Services (IBS) can be defined generally as an array of facilities and services (sub-systems) which are provided for an office complex, a telecommunications centre, a data processing centre etc. and which are connected to, controlled, monitored and managed by a computerised system. In the last ten years, Telecom Australia has provided and installed several computer controlled building Automation systems for a number of large telecommunications centres in Australia. The systems are given the name of Local Monitoring and Control Systems (LMCS) and provide primary control and monitoring services in a localised area. The basic purpose of the LMCS is to monitor and control air conditioning systems, power supply and distribution including emergency generating systems, fire detection, security and other systems in the building complex. Telecom Australia has taken steps to meet the challenge of the new trend in this field and is particularly interested in the design of and innovation in intelligent buildings. A system specification to serve as functional briefing for building developers has been developed for use in deliberations on requirements for Telecom Australia's proposed corporate Head Office complex in Melbourne and other major office accommodation complexes.","PeriodicalId":129305,"journal":{"name":"INTELEC '87 - The Ninth International Telecommunications Energy Conference","volume":"96 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1987-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126114303","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 : 1987-06-14DOI: 10.1109/INTLEC.1987.4794557
F. Tsai, Y. Chin, F. Lee
A novel constant-frequency, clamped-mode parallel-resonant converter is proposed and analyzed. Employing graphical state-plane techniques, five circuit operating modes together with their operating regions are defined, regions for natural and forced commutation are specified, and the dc control-to-output characteristics are derived. The predicted operating modes are experimentally verified using a 105kHz prototype circuit.12
{"title":"State-Plane Analysis of Clamped-Mode Parallel-Resonant Converter","authors":"F. Tsai, Y. Chin, F. Lee","doi":"10.1109/INTLEC.1987.4794557","DOIUrl":"https://doi.org/10.1109/INTLEC.1987.4794557","url":null,"abstract":"A novel constant-frequency, clamped-mode parallel-resonant converter is proposed and analyzed. Employing graphical state-plane techniques, five circuit operating modes together with their operating regions are defined, regions for natural and forced commutation are specified, and the dc control-to-output characteristics are derived. The predicted operating modes are experimentally verified using a 105kHz prototype circuit.12","PeriodicalId":129305,"journal":{"name":"INTELEC '87 - The Ninth International Telecommunications Energy Conference","volume":"89 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1987-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124602634","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 : 1987-06-14DOI: 10.1109/INTLEC.1987.4794553
H. Dolezal
The discription of the various system shows that the problems of each individual requirement will decide in favour of one or other UPS system. Computer systems with a frequency tolerances of +/- 1 % will definitely demand the use of NO-BREAK sets with static converter controlled synchronous motor drive. Space requirements are compartitively modest, as no battery equipment is needed for energy storage. These storage batteries alone would require considerable installation space, and here the size of the battery equipment will naturally depend on the power supply in connection with the transient battery operation. UPS generating sets, on the other hand, are not influenced by the time of mains failure which theoretically could last indefinitely The system with reversible machine and additional intigrated mains failure supply will be availible without extension of the installation space. Now and again, questions will arise with regard to the safty standard of such plants, in particular with a view on the performance of the heavy flywheel with possible faults or failure of the pedestal bearings.
{"title":"UPS - Dynamic-Rotary Systems with Flywheel and Diesel Engine","authors":"H. Dolezal","doi":"10.1109/INTLEC.1987.4794553","DOIUrl":"https://doi.org/10.1109/INTLEC.1987.4794553","url":null,"abstract":"The discription of the various system shows that the problems of each individual requirement will decide in favour of one or other UPS system. Computer systems with a frequency tolerances of +/- 1 % will definitely demand the use of NO-BREAK sets with static converter controlled synchronous motor drive. Space requirements are compartitively modest, as no battery equipment is needed for energy storage. These storage batteries alone would require considerable installation space, and here the size of the battery equipment will naturally depend on the power supply in connection with the transient battery operation. UPS generating sets, on the other hand, are not influenced by the time of mains failure which theoretically could last indefinitely The system with reversible machine and additional intigrated mains failure supply will be availible without extension of the installation space. Now and again, questions will arise with regard to the safty standard of such plants, in particular with a view on the performance of the heavy flywheel with possible faults or failure of the pedestal bearings.","PeriodicalId":129305,"journal":{"name":"INTELEC '87 - The Ninth International Telecommunications Energy Conference","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1987-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124182469","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 : 1987-06-14DOI: 10.1109/INTLEC.1987.4794598
Bjorn Rydland
The power supply division at Standard Telefon og Kabelfabrik A/S (STK) has developed a range of primary switched power supplies for 48V telecommunication equipment. The design of the largest rectifier, HFC 48/200, a 200A unit, was presented on INTELEC -83 in Tokyo by Mr. I. Narvhus. This paper deals with the experiences gained from the development and operation of this unit. The HFC 48/200 has been in production since 1985. Approx. 120 units are in operation as per March-87, feeding ITT1240 digital exchanges in Norway. The largest plant installed consists of 18 rectifiers, i.e. 3600A. The main subjects discussed are as follows: Design and specifications. Experiences with the chosen design, presented at INTELEC-83, emphasizing the transistor chopper, internal noise problems and the control circuits for ripple regulation and parallel operation. The HFC 48/200 meets or exceeds all the Norwegian Telecommunications Administration (NTA)s requirements. EMC. General considerations about EMI problems in switch mode power supplies (SMPS). Mains and output EMI filtering of SMPSs feeding telecommunication equipment. Measurements of EMI on the HFC 48/200 and HFC 48/33. Operational experience. The designs chosen for the transistor chopper and base drive circuits have proven its reliability. Both experiences concerning harmonic distortion on the mains and parallel operation are discussed.
{"title":"Experiences from Development and Operation of Switch Mode Power Supplies for Feeding of Electronic Telecommunication Equipment and Charging of Stationary Pb-Batteries","authors":"Bjorn Rydland","doi":"10.1109/INTLEC.1987.4794598","DOIUrl":"https://doi.org/10.1109/INTLEC.1987.4794598","url":null,"abstract":"The power supply division at Standard Telefon og Kabelfabrik A/S (STK) has developed a range of primary switched power supplies for 48V telecommunication equipment. The design of the largest rectifier, HFC 48/200, a 200A unit, was presented on INTELEC -83 in Tokyo by Mr. I. Narvhus. This paper deals with the experiences gained from the development and operation of this unit. The HFC 48/200 has been in production since 1985. Approx. 120 units are in operation as per March-87, feeding ITT1240 digital exchanges in Norway. The largest plant installed consists of 18 rectifiers, i.e. 3600A. The main subjects discussed are as follows: Design and specifications. Experiences with the chosen design, presented at INTELEC-83, emphasizing the transistor chopper, internal noise problems and the control circuits for ripple regulation and parallel operation. The HFC 48/200 meets or exceeds all the Norwegian Telecommunications Administration (NTA)s requirements. EMC. General considerations about EMI problems in switch mode power supplies (SMPS). Mains and output EMI filtering of SMPSs feeding telecommunication equipment. Measurements of EMI on the HFC 48/200 and HFC 48/33. Operational experience. The designs chosen for the transistor chopper and base drive circuits have proven its reliability. Both experiences concerning harmonic distortion on the mains and parallel operation are discussed.","PeriodicalId":129305,"journal":{"name":"INTELEC '87 - The Ninth International Telecommunications Energy Conference","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1987-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130109965","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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