Showing papers by "Hydro-Québec published in 1980"

Modeling and Resolution of the Medium Term Energy Generation Planning Problem for a Large Hydro-Electric System

Abstract: This paper is concerned with the modeling and resolution of the energy generation planning problem of a large hydroelectric system for a horizon up to two years, with emphasis on hydro plant generation, hydro system aggregation, and objective function modeling. The problem has been formulated as a deterministic discrete-time optimal control problem, with linear transition equations, a highly nonlinear objective, and bounds on both the state and the control variables. The solution algorithm is of the reduced gradient type, with the control variables nonbasic to provide good conditioning. Because of the linear relationship between the state and control variables, the set of feasible directions at a point is a polyhedral convex cone and the bounds both on the state and control variables can be accounted for by means of an algorithm for the orthogonal projection of the gradient on the cone. Some computational experience with this large-scale non-linear program is given, followed by a discussion of implementation.

Electrode Design for Testing in Uniform Field Gaps

Abstract: The efficiency of producing uniform fields in the test gap was evaluated for practical electrode configurations corresponding to the plane, the Rogowski and the Bruce profiles. The field intensity was calculated using the known charge simulation method and the calculated distributions of the field intensity at the surface of different electrode configurations were compared. The results obtained show a pronounced end effect at plane-profile electrodes. With the Rogowski profile, the effective uniform-field region is dependent on the gap spacing. The Bruce profile was found to be a good compromise, with a negligible end effect and a nearly constant uniform field region. Practical considerations are also presented together with the limitations of various profile configurations in the design of uniform field electrodes.

Measurement of Bus Voltage Angle Between Montreal and SEPT-ILES

Abstract: A new and precise measurement of bus voltage phase angle is described. We will show how the use of two adequately synchronized clocks allows an accurate measurement to be made of a bus voltage angle in real time. We describe the method used for synchronizing the clocks by means of LORAN C signals. We give experimental results of the bus voltage angle which was measured every second with a precision better than one degree.

Lateral Weir Flow Model

Abstract: The theory of flow through a lateral conduit outlet has been adopted to derive an expression for the discharge coefficient of the flow through a lateral weir set in a rectangular channel. The theoretical expressions hold good for subcritical flow in the channel upstream of the weir. The experimental data obtained in a test flume provide a verification of the theoretical relationships between the geometric and fluid dynamic parameters of the weir flow. The proposed relationships are valid for flow through lateral weirs that can be as wide as the parent channel.

The Influence of Spacer Dynamic Properties in the Control of Bundle Conductor Motion

Abstract: This paper presents the results of a field investigation on systems of either damping or non-damping articulated spacers with regards to aeolian vibrations, wake-induced oscillations and rain vibrations. Each test out of a program of five was systematically carried out on a comparative basis at the Magdalen Islands test line. It is shown that a low stiffness is desirable in spacer-dampers but that damping capacity is not a must for the attenuation of subspan oscillation.

Device for detecting and measuring the concentration of gaseous hydrogen dissolved in a fluid

Abstract: Discloses is an improved device to facilitate detecting and measuring the concentration of gaseous hydrogen dissolved in a fluid. A polymeric membrane is in contact with the fluid and permeable to the hydrogen gas. An electrolyte is provided which is capable of producing oxidation of the hydrogen diffused through the membrane at a first electrode, and reduction of an oxygen-containing gas such as air, at a second electrode. The connection of a measuring device across the electrodes measures the intensity of the current generated by the electrochemical reaction of oxidation of the hydrogen gas. The electrodes and the electrolyte are mounted in an electrode mounting unit which includes a first, tightly sealed enclosure encased within a second, tightly sealed enclosure. The mounting unit is tightly mounted into a hollow housing. This housing is fixed to a base across one extremity of which extends the polymeric membrane.

Microwave Repeater Power Supply Tapped From the Overhead Ground Wire on 735 kV Transmission Lines

Abstract: The presence of electrical energy in the overhead ground wire on transmission lines has been known for many years. Its possible utilization in remote areas offers many advantages but unfortunately due to technological problems, the access to this source was very difficult. Hydro-Quebec, as a utility interested in this energy source, asked its Research Institute to carry out studies of its possible applications. Very encouraging results have been obtained and this paper describes the various solutions examined with a view to make use of such available power at low cost together with the solution adopted for building an operational 35 kW prototype; this prototype was developed for the microwave repeaters of James Bay project.

System for sensing current in high voltage transmission lines utilizing the transmission of digital information by optical fibers

Abstract: A system and a method for sensing and reproducing a measured current value on a high voltage transmission line. An input shunt means (11) senses a current to be measured. A transmitter circuit transmits a sampled current value of the current passing through the shunt means. The transmitter has converter circuits (21, 22) for reproducing a composite output digital coded signal representative of the sample current value. A light transmitting output means (28, 29) is provided for transmission of the composite output digital coded signal on an optical fiber transmission line (12) to a receiver circuit. The receiver circuit has decoding circuit means for decoding and reconstituting the coded signal to a usable form to determine the sampled current value.

Electrostatic-Field Optimization of the Profile of Epoxy Spacers for compressed SF6-Insulated Cables

Abstract: Electrostatic-field optimization of the profile of the gas-dielectric interface was studied as a means of improving the dielectric performance of epoxy spacers. An optimum disc-shaped spacer was defined with a dielectric cone angle of 750, assuming a dielectric constant of the epoxy resin of 5 or higher. The dielectric performance of the optimum disc-shaped spacer is found to be limited, however, to about 85% of that of the conductor system without spacer.

Digital Impulse Recorder for High-Voltage Laboratories

Abstract: A digital recorder has been developed for use in HV laboratories as a prospective replacement for conventional impulse oscilloscopes. The new apparatus has a sufficiently high time resolution to record the fastest microsecond impulses used for HV testing and also allows slower switching transients to be monitored.

Gain limitations in TE CO 2 laser amplifiers

Abstract: The factors which limit the small-signal gain of TE CO 2 laser amplifiers are investigated with a novel technique based on gain measurements of the sequence, hot, and regular CO 2 laser bands. This new technique enables us, for the first time, to determine accurately and independently the rotational and vibrational temperatures characterizing the CO 2 laser system. The gain ratio of the sequence band (00° 2) to the regular band (00° 1) provides a simple and accurate determination of the ν 3 mode vibrational temperature. It is found experimentally that the ν 3 mode vibrational temperature saturates at a high input discharge energy. This saturation sets an upper limitation to the gain attainable in TE CO 2 laser amplifiers. As we can measure all the characteristic temperatures relevant to the gain medium, a detailed comparison between the calculated and experimental gain can be carried out with no variable parameters. The result of such a direct comparison confirms both the validity of the conventional "mode temperature" model for CO 2 laser dynamics and the validity of our measurement technique for vibrational temperatures.

Survey on Power System Grounding Design Practices

Abstract: This paper describes the results of a survey conducted among various Electric Utilities around the world. This survey was sponsored by IEEE working group 78.1 which is presently in charge of revising and updating IEEE guide No. 80 [1]. The intend of the survey is to get acquainted with the actual international practices and methodology followed by the utilities for the design of Power System grounding electrodes, and to determine the main disadvantages or drawbacks, if any, which are beli, eved to exist in the present edition of IEEE guide No. 80, when it is used by the electric utility.

Creating stable tokamak reactor equilibria by supplemental heating

Abstract: It is shown that temperature-dependent supplemental heating can be used to prevent thermal runaway in a tokamak reactor by creating stable equilibria at desired operating points with temperatures below ignition. HFCTR is used as an example, and it is shown that large Q (>20) can be obtained at modest temperatures (< 13 keV) by using power inputs of the order of 3–30 MW. The effect of thermal fluctuations is addressed, and it is shown that a control time delay of ~ 0.5 – 1.5 s can still maintain stable operation.

Effect of impurity particles on transformer oil under normal operating conditions

Abstract: A systematic survey was conducted of transformer oil samples taken from operating transformers and reactors used in Hydro-Quebec's transmission system. It was found that the particle content in the oil follows a distribution of the power function type and that it can be related to the dielectric strength of the oil and constitutes a good indication of the overall performance of the apparatus. Filtering the oil reduces the particle content and improves its dielectric strength.

Fast Steady-State Solution for HVDC Analysis

Abstract: A novel method for finding the steady-st4te solution in HVDC analysis is reported. The method is fast, economical and accurate because it exploits fully the properties of periodicity-in-T, transposed periodicity-in-T/6, balanced 3-phase symmetry in the ac circuit, and the properties of linear circuit theory. The method contributes towards making the digital computer a working tool for HVDC analysis.

Influence of a conducting particle attached to an epoxy resin spacer on the breakdown voltage of compressed-gas insulation

Abstract: The paper constitutes a systematic experimental investigation into the influence of a conducting wire particle attached to an epoxy resin spacer on the breakdown voltage of a coaxial electrode system. The work comprised tests in compressed SF 6 , N 2 and SF 6 -N 2 mixtures in the pressure range of 0.1 - 0.4 MPa abs. The position or the particle on the spacer with regard to the high-voltage electrode and its orientation were varied systematically. The tests were carried out under 60 Hz and lightning impulse voltages. The results shed light on the relative severity of particles attached to electrodes and spacers, and on the sensitivity of gas mixtures to particle contamination.

Statistical Significance of Test Methods for Low Probability Breakdown and Withstand Voltages

Abstract: A systematic evaluation of the statistical significance of different test methods currently used for the determination of the breakdown and withstand voltages was made. The breakdown probability of the test voltages was evaluated by both direct calculation and computer simulation of the test methods, assuming a known intrinsic breakdown probability in a single voltage application (or one cycle ac). The latter was assumed to be of either normal, smallest values or Weibull type, and to be unaffected by the event occurring in the pre- ceding voltage applications (or ac cycles).

Electron Energy Transport into Layered Targets Irradiated by C O 2 -Laser Light

Abstract: Inward energy transport ranges in layered targets have been measured as a function of the irradiance of short-pulse C${\mathrm{O}}_{2}$-laser light. As electromagnetic ponderomotive effects become important, the penetration of thermal electrons is sharply reduced and the penetration of suprathermal electrons increases much more slowly with irradiance. These results are discussed in the context of target implosions driven by suprathermal electrons.

Method and system for measuring frequency deviation of low frequency signals

Abstract: A method and a system for frequency measuring or monitoring and particularly suitable for power system frequencies in the range of approximately 0-2 KHz is disclosed. The technique is suitable for single-phase or three-phase periodic signals. Synchronism of sampling to power systems waveform and zero crossing detection are not required. The method is particularly attractive when used in conjunction with other on-line digital processing/control tasks since the interface between the power network and the computer may be shared and the fast and accurate detection of frequency variation can be beneficially used by the rapid digital processors.

Variable ratio transformer and static balance compensator

Abstract: Variable ratio transformer constructed around a control transformer comprising: two closed magnetic circuits each constructed around a ferromagnetic core. An alternating current magnetic field circulates in the first core and a direct current magnetic field circulates in the second core. The two circuits are located so as to define at least two common magnetic spaces in which the fields are superposed orthogonally. Around the first core is wound a primary winding, a secondary winding and, for a specific application in a three-phase circuit, a tertiary winding. A conventional transformer can be associated with the control transformer to reduce the load supported by the control transformer. The variable ratio transformer according to the invention can be used as a static balance compensator.

In Situ and Powder Metallurgy Multifilamentary Superconductors: Fabrication and Properties

Abstract: In recent years there has been an increased interest in alteranate technologies for producing multifilamentary composite super-conducting materials for large scale applications. We will discuss our development of both the in situ and the powder metallurgy processes which have involved a collaboration with a number of sicentists from several countries. Both processes show promise. Some highlights will be presented here; further details can be found in the references. Examples of Cu-Nb-Sn and Cu-V-Ga multifilamentary materials prepared by the in situ process and Cu-Nb-Sn using the powder metallurgy technique, are discussed here.

Interlaboratory Comparison of EHV Shunt Reactor Loss Measurements

Abstract: A comparison of loss measurements on a 0.002 power factor, 110 MVA, 735 kV shunt reactor at the Hydro-Quebec Institute of Research using four different bridges from three independent laboratories, is described. The special features of the bridges, which were all basically of the three-winding transformer (current comparator) type, are discussed and their estimated uncertainties are given. In the region where all bridges were judged to be operable, the measured values lie within ±3% of the mean. For the two bridges which were specifically adapted for shunt reactor loss measurements, the measured values are within ±1% of the mean. The test conditions, results, and some of the problems encountered are discussed and recommendations for future comparisons are made.

Supplying Fixed and Stroboscopic Light Beacons From the Overhead Ground Wire on 735 kV Transmission Lines

Abstract: The increased use of fixed and stroboscopic light beacons to mark the location of Transmission Line Towers forced Hydro-Quebec as utility to look upon an economic system for supplying those beacons, especially in remote areas. Electrical energy induced capacitively in an insulated section of overhead ground wire was an interesting approach and so a system was devised for supplying both fixed and stroboscopic light beacons with power derived directly from the overhead ground wire of the transmission line itself. This paper describes then a low cost solution adopted for building operational prototypes to energize beacon lights on Hydro-Quebec 735 kV system.

The Effects of Mechanical Stresses on the High Field Critical Current Density of in Situ Multifilamentary Nb3Sn Wires

Abstract: Progress in the development of Nb3Sn in situ multifilamentary superconductors has demonstrated that these materials compare favorably with the best commercial multifilamentary Nb3Sn [1–3] wires. Overall critical current densities in excess of 10 kAJcm2 at 14 T have been achieved [4]. Furthermore, results presented in these conference proceedings [5] and earlier results [6,7] all indicate that the mechanical properties of in situ multifilamentary superconductors are better than those of conventional materials; e.g., the degradation of the critical current density with uniaxial tension is displaced towards a larger stress value. This paper summarizes and analyzes the stress-strain results at 4.2 K for a number of composites and discusses the applicability of the simple prestrain model to explain quantitatively the peak in J c vs. e based on the latest results.

A Study of Morphology in Polyethylene Filled with 3-Percent Carbon

Abstract: Samples of polyethylene filled with 3-percent carbon were cooled from the melt at rates ranging from 104 to 10-1 C/min. The resulting degree of crystallinity, as measured from wide angle X-ray diffraction and density, was studied. Variations in the degree of crystallinity between 46 and 68% were observed. The role of morphology on the conduction properties of partially crystalline polymers is discussed.