Showing papers in "Canadian Electrical Engineering Journal in 1979"
TL;DR: In this article, it is shown that it is possible to construct scaled physical models in which the electromagnetic and thermal phenomena of the full scale system can be modelled simultaneously, by simulating electromagnetic frequency and thermal events on different time scales.
Abstract: Maxwell's equations and the thermal equation for heat flow are examined and scaling criteria are developed which show that it is possible to construct scaled physical models in which the electromagnetic and thermal phenomena of the full scale system can be modelled simultaneously. Simultaneous modelling is made possible by simulating electromagnetic frequency and thermal events on different time scales. It is also shown that simultaneous modelling of electromagnetic and thermal phenomena can be carried out when the electrical conductivity of the medium of the full scale system is temperature dependent. The electrical and thermal properties of oil sand and the general problem of in-situ recovery of oil the reform have been used to guide the development of the modelling criteria. The results obtained can be applied to a large class of other problems as well as the electromagnetic heating of food stuffs and biological tissue.
17 citations
TL;DR: In this paper, a systematic study and analysis of the various modulation strategies for three phase pulse width modulated (PWM) inverters is presented, where analytical expressions are derived to obtain harmonic components of output voltages for duty ratio, sine, triangular and step modulation.
Abstract: Presents a systematic study and analysis of the various modulation strategies for three phase pulse width modulated (PWM) inverters. Analytical expressions are derived to obtain harmonic components of output voltages for duty ratio, sine, triangular and step modulation. A comparative study of the merits and demerits of the various modulation technique is presented. The effects of ratios of carrier and reference frequencies, and the instant of synchronisation are investigated. Use of a particular modulation strategy for a particular application is discussed.
15 citations
TL;DR: A forecasting model for discrete approximations to the load duration curve is developed using Box-Jenkins time series analysis and results are extremely good, indicating that while a larger number of approximation perform marginally better, there is nothing to lessen the advantage of using only a six-step approximation.
Abstract: The load duration curve is a primary tool used in the economic analysis of electric utility operations and for the purpose of planning new construction. In general equilibrium models and also in other models using linear programming, piecewise linear approximations to the load duration curve are required. This paper endeavors to develop a forecasting model for such discrete approximations using Box-Jenkins time series analysis. A model is structured and estimated for six, twenty, and fifty discrete approximations for two utility regions in the United States. The forecast results are extremely good, indicating that while a larger number of approximations perform marginally better, there is nothing to lessen the advantage of using only a six-step approximation.
8 citations
TL;DR: The main purpose of this paper is to report on the implementation of the error locator polynomial, and the Chien's search for finding the error locations, using the table look-up technique suitable to a microprocessor based decoder.
Abstract: Presents some preliminary results on the implementation of a binary BCH decoder involving a combination of specially designed hardware for some operations and a software implementation on a microprocessor for the remaining operations. With such a microprocessor based decoder, a large number of different BCH codes can be accommodated with little or no hardware changes. The decoding task is a function of the software and thus allows common hardware to support a wide range of functions. The main purpose of this paper is to report on the implementation of the error locator polynomial, and the Chien's search for finding the error locations, using the table look-up technique suitable to a microprocessor based decoder.
5 citations
TL;DR: A load flow technique which provides an approximate solution of the bus voltage magnitudes and phase angles in a single iteration is described and the effectiveness of this technique for contingency evaluation is investigated.
Abstract: In power system reliability applications, an approximate load flow solution of each contingency state is normally sufficient to determine if the desired limits of bus voltages and line ratings have been violated. The total possible line outage states to be investigated for a practical system are very large. A.C. load flow techniques are computationally expensive whereas a d.c. load flow technique does not provide the bus voltage magnitudes. In this paper, a load flow technique which provides an approximate solution of the bus voltage magnitudes and phase angles in a single iteration is described. The suitability of this approach for obtaining load flow solutions of test systems ranging from 5 to 118 buses is briefly discussed. The effectiveness of this technique for contingency evaluation is also investigated.
5 citations
TL;DR: In this paper, transient stability evaluation of a power system from a probabilistic viewpoint is discussed, and the random nature of the basic factor such as the type, location, and clearance of faults which affect the transient stability performance is demonstrated.
Abstract: Discusses transient stability evaluation of a power system from a probabilistic viewpoint. The random nature of the basic factor such as the type, location, and clearance of faults which affect the transient stability performance is demonstrated. Consideration of these aspects for simple single machine-infinite bus and multimachine systems is illustrated using two example systems. Methods of extending the basic approach to practical systems together with the difficulties and possible methods of solution in a comprehensive analysis are indicated.
5 citations
TL;DR: In this paper, the principle of operation and physical details of a device for measuring electric fields and ionic currents caused by very high voltage d.c. transmission lines are described.
Abstract: Describes the principle of operation and the physical details of a device for measuring electric fields and ionic currents caused by very high voltage d.c. transmission lines. The authors present results of measurements made under different conditions, and compare them with theoretical results. The measuring apparatus was subjected to testing for a period of about a year and a half, under different climatic conditions, under the experimental line at IREQ. The results obtained show the suitability of this equipment for long-term tests under all climatic conditions.
4 citations
3 citations
TL;DR: In this paper, the authors present some results of the Bay of Fundy tidal power potential reassessment studies carried out during 1976-77, and a brief description is given of the analytical approach to energy production modelling and optimization studies for the three most attractive sites.
Abstract: Presents some results of the Bay of Fundy tidal power potential reassessment studies carried out during 1976-77. A brief description is given of the analytical approach to energy production modelling and optimization studies for the three most attractive sites. The system modelling used for studying integration of tidal generation into the Maritime Integrated Power Systems is reviewed and some preliminary results of the economic evaluation of tidal power sites are presented.
3 citations
TL;DR: In this article, a research and development program leading to the demonstration of safe, permanent disposal of immobilized wastes deep underground in stable rock formations is outlined, and the program is designed to maintain the option of disposing of the used fuel itself or of processing wastes should Canada decide to recover and recycle the fissile material to extend fuel resources.
Abstract: Used fuel from the CANDU-PHW reactor is safely stored in water-filled pools at the reactor site. Methods have been developed for long-term storage if this is required. The research and development program leading to the demonstration of safe, permanent disposal of immobilized wastes deep underground in stable rock formations is outlined. The program is designed to maintain the option of disposing of the used fuel itself or of disposing of processing wastes should Canada decide to recover and recycle the fissile material to extend fuel resources.
2 citations
TL;DR: In this paper, the feasibility of extracting the energy commodities from coal, oil sand, and heavy oil, heating the deposits by electric and magnetic fields, was investigated and the tentative conclusions drawn are that all these solid fossil fuels can successfully be processed underground.
Abstract: A study has been made to determine the feasibility of extracting the energy commodities-electricity, gas, petroleum, coke, and chemical feedstocks-from coal, oil sand, and heavy oil, heating the deposits by electric and magnetic fields. Available electrical and chemical data indicate that this process may be technically and economically feasible. Some basic data are missing, and it has been necessary to indicate possible ranges of values for some parameters. The tentative conclusions drawn are: all these solid fossil fuels can successfully be processed underground. All five energy commodities can be produced economically in adequate quantities for a period of a century or more, without recourse to any other major energy source. The development and construction time required is short enough to permit an uninterrupted supply of energy commodities as present sources decline.
TL;DR: The problem of implementation of two-dimensional infinite impulse-response digital filters is considered and an algorithm is proposed for filters which are factorable into bilinear second-order sections with complex coefficients.
Abstract: A brief tutorial background on the design of two-dimensional digital filters is presented. A technique for designing stable two-dimensional recursive filters is summarized and an algorithm useful for controlling the cutoff frequencies is discussed. The problem of implementation of two-dimensional infinite impulse-response digital filters is then considered and an algorithm is proposed for filters which are factorable into bilinear second-order sections with complex coefficients. Computational errors due to the finite wordlength of the filters are analyzed. These errors can be represented by a set of error sequences additively contaminating the output of an ideal realization. The transfer functions relating these error sequences to simple roundoff errors are derived. The problems of data management when large matrices are stored in auxiliary storage are also discussed and a solution is proposed.
TL;DR: The theoretical concept of applying matching primary feed devices to illuminate offset parabolic reflectors is studied in this paper, where the physical interpretation of how this new class of feeds compensates for the geometric asymmetry of the offset system is explained.
Abstract: The theoretical concept of applying matching primary feed devices to illuminate offset parabolic reflectors is studied. The physical interpretation of how this new class of feeds compensates for the geometric asymmetry of the offset system is explained. An economical technique to investigate the corresponding improvements in the near-axis radiation is given by suitably extending the modified stationary phase method, suggested in the literature, to the added modal behaviour of these feeds. The analytical developments and their respective novel results are accumulated relative to the main and basic parameters of offset antenna systems. The presentation is given in some detail so that it may be a useful paper for a wider group of readers.
TL;DR: In this article, the effect of ice-covered elements on the pattern and impedance characteristics of a UHF Yagi antenna was investigated and design guidelines to minimize the detrimental effects of the ice were proposed.
Abstract: Results of an experimental study to determine the effect of ice-covered elements on the pattern and impedance characteristics of a UHF Yagi antenna are given. Practical design guidelines to minimize the detrimental effects of the ice are proposed.
TL;DR: The relative freedom of the Canadian Arctic from environmental effects due to human activities and the presence of many small isolated communities dependent on their own electric power generating systems provides an interesting opportunity for a comparative cost/benefit study of possible electrochemical energy storage systems as mentioned in this paper.
Abstract: The relative freedom of the Canadian Arctic from environmental effects due to human activities and the presence of many small isolated communities dependent on their own electric power generating systems provides an interesting opportunity for a comparative cost/benefit study of possible electrochemical energy storage systems. The high cost of fuels in the Arctic encourages the design and operation of maximum efficiency energy delivery systems. The elimination of waste at each step is environmentally and economically desirable.
TL;DR: In this paper, a digital signal processor, operating at baseband, is described for the scanning of a Mills' cross array antenna, which uses time modulation to scan the pencil beam produced by the array.
Abstract: A digital signal processor, operating at baseband, is described for the scanning of a Mills' cross array antenna. The processor uses time modulation to scan the pencil beam produced by the array. The principles of time modulation scanning are reviewed. Experimental results are included to demonstrate the practical feasibility of the digital baseband processor for scanning the array along prescribed look directions inside the region of interest.
TL;DR: In this paper, the authors review and discuss developments in optimal excitation control of synchronous generators, taking non-linear aspects of the power system into account, and assess various methods of solution for practical application purposes.
Abstract: Reviews and discusses developments in optimal excitation control of synchronous generators. The control problem is stated, taking non-linear aspects of the power system into account. Various methods of solution are described and assessed for practical application purposes. An approach in which the control is formulated by a first order term plus a set of higher order terms, representing non-linear components, appears to offer distinct advantages with respect to computing effort and application. Some results of system studies, incorporating optimal excitation control by this approach, are presented and discussed briefly in the paper.
TL;DR: In this article, the authors present the results of an investigation made with Canadian electrical companies in order to evaluate the needs and applications of fiber optics, and show the system, giving certain technical details about the physical installation, equipment and its functioning.
Abstract: First sums up the results of an investigation made with Canadian electrical companies in order to evaluate the needs and applications of fiber optics. The paper defines the structure of an experimental installation which uses fiber optics, and then shows the system, giving certain technical details about the physical installation, equipment and on its functioning. Finally some results are given.
TL;DR: By means of these non-linear filters (Feher's processor) it is possible to approach the Nyquist channel shaping without any intersymbol interference and without jitter.
Abstract: The principle of operation and the implementation of a new bandwidth-efficient family of non-linear filters is presented. By means of these non-linear filters (Feher's processor) it is possible to approach the Nyquist channel shaping without any intersymbol interference and without jitter. An application of this filter (processor) is in digital Single Channel Per Carrier (SCPC) Satellite Systems in which the random NRZ data stream is severely filtered prior to modulation. Measured results show that the integrated out-of-band power is 20 dB below the in-band power.
TL;DR: In this article, the basic ingredients of some fundamental scheduling problems are highlighted and a discussion of potential directions for theoretical research aimed at improvements in the currently available methodology and algorithms are also outlined.
Abstract: Deals with some Canadian research and development needs in the area of optimum scheduling of hydro and thermal plants in integrated electric energy systems. The basic ingredients of some fundamental scheduling problems are highlighted first. This is followed by a discussion of potential directions for theoretical research aimed at improvements in the currently available methodology and algorithms. Opportunities for hardware development for on-line and off-line implementation are also outlined.