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In this presentation we address the special features and advantages of the gas turbine, and the single shaft turbine in particular, as a driver for standby generating sets. A few words about the expression "Gas Turbine." Many think that a gas turbine, as the expression implies, solely burns gaseous fuels. This is not correct. It is true that gaseous fuels of different qualities are excellent...
As indicated in the title this paper deals with the experience attained from operation of hybrid power systems (i.e. systems relying on multiple sources of energy to ascertain continuous operation of telecom equipment with one or more inactive power sources), incorporating wind generators in remote telecom stations located in an arctic environment. Although the functional layout of such systems will...
Remote hybrid power systems, including renewable power sources, are for long term safe operation, depending on the correspondence between the actual powers of nature on site and the estimations made when designing the system. Two options are available to secure safe operation, either costly oversizing or long term monitoring for later corrections. The alternative of long term monitoring of remote...
The review of the fundamental ideas on which the linear dynamic analysis of switched-mode power-processing cells is based shows that the low-frequency and the small-amplitude restrictions combined which the notion of the controlled quantity permit the establishment of a truly general linear model of these structures with time-varying topology. The model obtained comprises two dependent generators...
A buck-type converter is modeled for continuos conduction mode, simulated, analysed and measured with emphasis on loop gain to be able to design for stability. As a result of this "Structured Analog Design" process, a new SPICE2 model for current-mode programming plus a useful formula for control voltage to output voltage transfer function has been derived. The theoretical background is...
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...
A two-transistor flyback-converter, originally built to be used as a measure object for measuring electromagnetic interference is thoroughly analyzed by using the circuit analysis programme KREAN. the flyback converter is operated in current-mode using the switchmode control-IC UC3842. Input voltage is 230 V mains. The output is on multiple windings with a total power of 260 W. The analysis is split...
This paper presents the EMC specifications for the supplying of UPS (uninterruptible power supply) for district energy distribution control centres and the proper immunity test procedures developed by the ENEL (Italian Electricity Board) to qualify the UPS electromagnetically, by type tests that reproduce the different types of interference, caused by different possible sources. A UPS designed to...
Voltage disturbances of all types occur in different geographic areas of the United States. The effects of these disturbances on large computers and data processing centers have been published in studies over the last two decades. This paper will evaluate power line disturbances as they affect today's trends toward distributed power, the proliferation smaller computers and lower operating voltages...
In the course of current technological progress, the power ratings of minicomputer systems which require an uninterruptible power supply have been generally decreasing. At the same time, the computing capacity of the units has greatly increased. Consequently the demand for computer-aided systems for development, design, manufacturing and management has risen enormously, even for applications in smaller...
The different blocks (rectifier, inverter, static bypass switch) in the three phase UPS model B312 are briefly discussed. The input characteristics of the commonly used diode/capacitor rectifier are discussed by analysing the input current waveform with and without a small inductor in the circuit. The source impedance influence on the total performance is stressed separately. In a three phase system...
This paper describes a basic, adaptive ac-input algorithm applied to a microprocessor-controlled parallel-processing Uninterruptible Power Supply (UPS) with a short battery holdover. The algorithm dynamically modifies the ac-input line switch operating-thresholds, which are based an the UPS output load current and ac-input voltage, ensuring that battery-energy is preserved for periods in whtch the...
A small UPS using phase control has been developed. The isolation transformer used in the phase-controlled inverter is extremely minimized by the high frequency switching. This inverter is of simple construction and allows bidirectional power flow. The basic operation of the phase-controlled inverter and its applications to UPS are presented with some experimental results.
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.
This paper proposes a high performance multi-functional inverter and its several applications for UPS systems. High frequency PWM voltage source inverter using high speed switching devices such as BIMOS are adopted as the multi-functional inverter. The inverter has current minor control loop and functions as a sinusoidal wave voltage source, an active harmonic suppressor and a high power factor charger...
This paper describes some aspects in utilizing GTO's in a new UPS-convertor. Comparasion is made between convertors based on conventional thyristors. An unique protection system and a new snubber circuit are also described.
In the power range of 10 to 80 kVA, remarkable progress in the use of new technologies is modifying deeply the performances, the installation and the use of U.P.S equipment. New power and control electronic devices, manufacturing processes and Computer Aided Design (C.A.D) offer opportunities for a new generation of U.P.S to the greatest benefit of the user.
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