Showing papers on "Electric power published in 1974"

Electric power converter

Abstract: A programmed switching system for converting direct current into alternating current or some other variable current, or for converting alternating current of one frequency into alternating current of another frequency. The system employs a number of stages connected in cascade. Each stage includes an electrical energy source or an electrical energy storage unit and switch means adapted to bypass the energy source or storage unit, to interconnect the source or storage unit with other electrical energy source or storage units across a load in a programmed fashion, and to reverse the direction of current flow in the load to apply, for example, a quasi-sinusoidal voltage across the load.

Power system modeling

Abstract: A discussion of the philosophy of modeling of three-phase transmission lines, three-phase transformers, three-phase generators, and power system loads is presented. Although the topic is very basic, the material covered is not all conventional. Single-phase representation of a three-phase power system is discussed in detail. Assumptions usually employed in the power industry are stated. Also discussed is the mathematical representation of a non-symmetrical three-phase power system in which the symmetrical-component method is not applied. An important aspect is the study of the models used in present-day problems as well as the models that may be required in the near future.

Real-time computer control of power systems

Abstract: A dramatic transformation in system monitoring and control is taking place in the electric utility industry. New control centers are being equipped with multiprocessor real-time computers scanning and controlling the generation and transmission system via high-speed data-acquisition subsystems and interacting with the human operator via dynamic, color, graphic displays. Within the computer as many as a hundred or more programs are available to run in a multiprogramming environment in response to changing power-system conditions and to operator's demands. The main objective of this new development in on-line control is the enhancement of the security of the power system in order to maintain a high reliability of electric power service. The concept of security control is discussed and the noteworthy features of its present state of development in recently designed and installed control centers are described.

Apparatus for starting aircraft engines and for operating auxiliary on-board power generating equipment

Abstract: Two aircraft jet engines are associated respectively with two sub-systems each comprised of a gas turbine for starting one of the engines and driving a set of secondary power generators such as hydraulic pump and electric generator and an air conditioning unit. The two sub-systems are drivingly cross-linked so that either gas turbine can drive both sets. The air conditioning units as well as the gas turbines receive tapped air from the engine compressors, whereby the gas turbines may run with or without combustion. An emergency power pack may be provided, preferably in selective driving connection to one of the sub-systems to provide for the possibility of starting a gas turbine and driving, if necessary, the power generators of that sub-systems or furnishing hydraulic and electric power on a emergency basis when all sub-systems have failed.

Bicycle with electric motor assist

Abstract: A pedal-operable bicycle is provided with supplemental electric power means to assist the operator in traversing hilly terrain. The electric power means comprises a storage battery, a wheel-hub mounted direct current motor operated either as a motor or a generator, and handle bar actuated electronic control means for applying power to energize the motor or to connect it as a generator to recharge the battery when traveling downgrade and/or to brake the vehicle to a slower speed. An alternate arrangement using a separate motor and generator is also disclosed.

Digital Wattmeter Using a Sampling Method

Abstract: Average electric power can be measured by a system that samples voltages and currents at predetermined intervals. The sampled signals are digitized and the result is computed by numerical integration. The response of the system agrees with that of a standard electrodynamic wattmeter within 0.02 percent from dc to 1 kHz, with the possible exception of zero power factor measurements. Measurements up to 5 kHz can be made with somewhat greater uncertainties.

Stability of large electric power systems

Abstract: Fifty-nine papers on the stability of electric power systems selected from various conferences and other sources are presented A separate abstract was prepared for each of 58 papers One paper has been previously included in the DOE Energy Data Base (LCL)

Electric traction transportation system with storage battery powered vehicles and fast recharge at the vehicle stops

Abstract: An urban mass transportation system is disclosed which makes use of storage battery powered vehicles. In view of the specific use which implies pre-established routing of the vehicles and preestablished stops at frequent intervals, the capacity of the batteries installed in each vehicle is commensurate to the capability of running for a limited distance. The vehicles are further provided with contact means, such as trolleys, for performing a fast recharge of the batteries at the stop stations, without removing the batteries. The stop stations are equipped with devices mating with the contact means and suitable for allowing a fast recharge. Electrical power is taken from an electrical distribution network independently from the routing of the vehicles.

Protection device for objects included in electrical power supply networks

Abstract: A protection device for lines, bus bars, transformers and the like in electrical networks includes for each object a directional wave detector arrangement with one detector unit per phase for sensing current and voltage transients occurring in the object in case of faults in the network. Each wave detector unit includes directional detecting devices and a plurality of level detectors connected with an output for tripping signals and an output for blocking signals. One directional wave detector unit is arranged for each connection to an object which is to be protected and is connected through level detectors to the logic system which compares the output signal from the directional wave detector for the object and disconnects the object in response to a tripping signal from any of the directional wave detectors only if none of the wave detectors has emitted a blocking signal.

Flow tubes for producing electric energy

Abstract: An apparatus for producing electrical energy from unused, wasted, running rivers, ocean tides, and the like without creating any air pollution or harming the environment; the apparatus consisting of large tubes sunken below the water so that the water can flow through, and turbine or impeller blades inside the tubes being turned by the water movement, the impellers driving electric generators which are connected by electric cables to power plants on shore from where the electrical power is distributed for consumption.

Technical change and scale economies in an engineering production function: the case of steam electric power

Abstract: An engineering approach can be used to analyze the economics of production processes in many industries in terms of the impact of technical and scale changes. In addition to statistical cross section and time-series studies made by observation, the engineering approach includes all physically feasible combinations of inputs. The steam-electric power industry is used as an engineering model to demonstrate processes (e.g., steam electric generation, oil refining, metal fabrication, etc.) on the basis of different machine characteristics. Results indicate that changes in prices of fuel and capital have an impact on design efficiency but not machine capacity in these industries. (38 references) (DCK)

Solar heat pump

Abstract: A heating and cooling system which uses heat derived from solar collectors to operate a heat engine which provides operating power to drive a heat pump/air conditioning system and including capability to operate either partly or wholly on supplementary energy sources such as an oil or gas furnace or electric power, and employing positive displacement heat engine and compressor units.

Communicating over power network within a building or other user location

Abstract: Power lines within a building or other user location are connected through a fuse and a filter to an external power grid that supplies power at the usual 50 Hz or 60 Hz. Communications apparatus such as a central computer and a number of typewriters is connected to the power lines within the building at at least two locations and transmits communications signals over the power lines. The communications signals have a frequency different from the frequency of the electrical power supplied by the external power grid and preferably in the audio range. The filter is tuned to pass the electrical power but substantially to block passage of the communications signals. Two important advantages are that the power lines within the building double as communications lines and that the building presents a purely resistive load to the external power grid, so that the grid has an improved power factor.

System and method for generation and distribution of electrical and thermal energy, and automatic control apparatus suitable for use therein

Abstract: Instead of supplying all electrical current for residences or similar buildings from a single central station by way of distribution power lines, each building is also provided with its own engine-driven electrical generator the output terminals of which are connected to the power lines. The heat from the engine in each building is used in satisfying the thermal load for that building, for example to heat the building and the domestic hot water, and/or to supply heat for heat-input forms of air conditioners or refrigerators. Thermostatic control is used to turn the engine on and off as needed to perform its heating function. The electrical current generated while the engine is running is used to supply part or all of the electrical load in the building, and any excess is supplied to the distribution power lines. A two-way watt-hour meter registers the net electrical power flow in or out of the building to enable securing of credit for the current delivered to the power lines from each building. The local generators are enabled by their connection to centrally-activated power lines, so that upon a shutdown of the central station or a break in the lines to central, any local generator connected to the then-deactivated power lines will automatically be prevented from delivering current to the power lines, as a protection to persons who may be working with the supposedly "dead" lines. This system produces significant improvements in the efficiency of use of fuel in producing electrical and thermal energy, and reduces thermal pollution of the environment.

Electric utility fuel choice behavior in the United States

Abstract: The views expressed herein are the authors' sole responsibility and do not reflect those of the Department of Economics or the Massachusetts Institute of Technology.

Assessment of the security of operating electric power systems using probability methods

Abstract: A review is given of probability methods which have been proposed for the assessment of the security of operating electric power systems. The goal of all the methods presented is to provide the system operator with a consistent, on-line, indication of system security in the near-term future as a guide for operating decisions. Mathematical models used in the various methods are described and data requirements are discussed. Finally, areas of desirable future investigation are outlined.

Tool carrying case

Abstract: There is disclosed an improved tool carrying case, specifically designed to accommodate equipment employed by electrical power supply line maintenance personnel for use as when ''''jumping'''' a power supply line around an electrical device requiring surveillance/replacement, or the like. The carrying case of the present invention is constructed to accommodate in improved manner a number of differently sized fuses, as well as the test tool parts per se.

Nuclear eclectic power.

Abstract: The uranium and thorium resources, the technology, and the social impacts all seem to presage an even sharper increase in nuclear power for electric generation than had hitherto been predicted. There are more future consequences. The "hydrogen economy." Nuclear power plants operate best at constant power and full load. Thus, a largely nuclear electric economy has the problem of utilizing substantial off-peak capacity; the additional energy generation can typically be half the normal daily demand. Thus, the option of generating hydrogen as a nonpolluting fuel receives two boosts: excess nuclear capacity to produce it, plus much higher future costs for oil and natural gas. However, the so-called "hydrogen economy" must await the excess capacity, which will not occur until the end of the century. Nonelectric uses. By analyses similar to those performed here, raw nuclear heat can be shown to be cheaper than heat from many other fuel sources, especially nonpolluting ones. This will be particularly true as domestic natural gas supplies become more scarce. Nuclear heat becomes attractive for industrial purposes, and even for urban district heating, provided (i) the temperature is high enough (this is no problem for district heating, but could be for industry; the HTGR's and breeders, with 600 degrees C or more available, have the advantage); (ii) there is a market for large quantities (a heat rate of 3800 Mw thermal, the reactor size permitted today, will heat Boston, with some to spare); and (iii) the social costs become more definitely resolved in favor of nuclear power. Capital requirements. Nuclear-electric installations are very capital-intensive. One trillion dollars for the plants, backup industry, and so forth is only 2 percent of the total gross national product (GNP) between 1974 and 2000, at a growth rate of 4 percent per year. But capital accumulation tends to run at about 10 percent of the GNP, so the nuclear requirements make a sizable perturbation. Also increasing the electric share of energy provision means increasing electric power utilization, which has a high technological content and demands yet more capital. Thus, provision of capital is a major problem ahead, especially for electric utilities. The need for people. The supply of available trained technologists, environmental engineers, and so on, especially in the architect-engineer profession, is insufficient for the task ahead, especially since the same categories of people will be in demand to build up a synthetic fuels industry and do other new things. Beyond these specific items and beyond the technological discussion, one can feel deeper currents running in this debate. Issues that started out seeming technological ended up being mainly societal: prevention of clandestine use, either by vigilance or by public spirit; a determination to maintain quality and to safeguard wastes that transcends narrow interests; a perception of social benefits and damage much more holistic than before; the need to manage programs more openly and better than before. Questions and doubts become more acute, answers and methods less sure. Here is a final question. We have never before been given a virtually infinite resource of something we craved. So far, increasingly large amounts of energy have been used to turn resources into junk, from which activity we derive ephemeral benefit and pleasure; the track record is not too good. What will we do now?

Energy policy in the u.s.

Abstract: THE ENERGY SHORTAGE IN THE U. S. WAS PREDICTABLE TWO YEARS AGO WHEN THE DOMESTIC SUPPLY OF FUELS BEGAN TO FALL SHARPLY BEHIND THE RISING TOTAL DEMAND FOR ENERGY. DOMESTIC PRODUCTION OF NATURAL GAS AND CRUDE OIL REACHED AN ALL-TIME HIGH IN 1972 AND HAS BEEN FALLING SINCE. GRAPHS ARE PRESENTED WHICH ILLUSTRATE THE U. S. DEPENDENCE ON IMPORTS AND THE AVAILABILITY OF LIMITED QUANTITIES OF SYNTHETIC GAS AND OIL AND HYDROELECTRIC POWER. IN ANY ATTEMPT TO FIND SOLUTIONS TO FIND SOLUTIONS TO THE PROBLEM, THE NEED IS INDICATED FOR AN OVERALL TAXONOMY OF ENERGY. THIS MUST CONSIST OF A LISTING OF THE OPTIONS IN A LOGICAL HIERACHY, SO THAT NATIONAL DEBATE LEADS TO PUBLIC ILLUMINATION AND EVENTUALLY TO SATISFACTORY CHOICES. THE ANALYSIS OF ALTERNATIVE SOLUTIONS TO TECHNICAL PROBLEMS IS REVIEWED AND THE PROCESS OF TECHNOLOGICAL DISCUSSION IS CONSIDERED. THE COMPARISON OF VARIOUS NUCLEAR METHODS FOR GENERATING NUCLEAR POWER IS CONSIDERED AS AN EXAMPLE. IMBALANCES IN THE FISSION PROGRAM ARE DETAILED. THE SERIOUS IMBALANCE IN THE BREEDER-REACTOR PROGRAM (WITH ITS BUDGET OF $320 MILLION) IS DISCUSSED. SIMILAR ASSESSMENTS ARE MADE WITH RESPECT TO ELECTRIC POWER AND SOLAR ENERGY. THE ALLOCATION OF PRIMARY ENERGY RESOURCES AMONG USERS IS CONSIDERED IN DETAIL. POSSIBLE INTERNATINAL IMPACTS ARE REVIEWED. ENERGY PROVISION VERSUS ENERGY UTILIZATION AND CONSERVATION IS NEXT DISCUSSED AND SEVERAL SUGGESTIONS ARE MADE FOR AMELIORATING FUTURE ENERGY DIFFICULTIES.

Temperature control system

Abstract: A temperature control system comprises a heat sink heatable upon application of electric power thereto, an AC power source for heating the heat sink, temperature detector means for detecting the temperature of the heat sink, and control means for controlling the electric power applied to the heat sink in accordance with an output signal from the detector means so that the heat sink maintains its required temperature. The control means is operable to cause application of a full power of the power source to the heat sink at the initial heating stage thereof and application of a partial power of the power source to the heat sink when the temperature thereof is in the vicinity of the required temperature.

Battery charging circuit

Abstract: Batteries in locations such as unattended telephone buildings are kept in a good and reliable condition by a circuit which provides a normal charge periodically, which provides a normal charge each time the primary electrical power fails and is restored, and which provides an equalizing charge for a predetermined length of time in response to a manual or automatic operation.

Electrical system for automotive vehicles and the like

Abstract: An electric power distribution system for automotive vehicles is disclosed. The system employs a bus bar which is connected to an electric power source and positioned within the vehicle in such a way as to provide a ready source of power near each power consuming device. Power control switches are coupled to control power transmission over relatively heavy conductors between the bus bar and each power consuming device. Light weight conductors are connected to the power control switches or power controllers to operate them in response to control signals provided over additional switch devices such as manually operated switches on the dashboard of the vehicle.

Uninterruptible electric power supply

Abstract: An electric power supply system for a load wherein two prime movers, a gas turbine and a synchronous electric motor receiving its motive energy from a source of electric power, such as a public utility, are utilized to simultaneously drive an electric generator. A fuel controller, which is responsive to the output of the generator, operates in an isochronous mode and regulates the supply of fuel to the gas turbine from a fuel source to bring the turbine, generator, and motor up to operating speed. A paralleling controller, which is responsive to both the output of the generator and the output of the utility power source connects the motor to the utility when the outputs of the generator and utility are of equal frequency and phase so that the motor shares the load in driving the generator. A power sensor compares the flow of electric energy to the motor with a fixed reference signal, and generates a resultant difference signal which is used to trim the turbine fuel controller to speed up or slow down the turbine so that constant power flows through the power sensor and motor, resulting in the motor always providing a fixed or predetermined amount of driving force to the generator while the turbine provides the rest. Additionally provided is a reverse current sensor, which detects interruption of current flow from the utility, and immediately disconnects the motor from the utility. The fuel controller now operates in an isochronous mode without trimming signals from the power sensor, and the turbine is thus controlled to provide all the needed driving force to drive the generator to maintain constant generator frequency and phase output. An overrunning clutch is utilized between the turbine and generator which allows easy disconnection of the turbine from the generator in the event the turbine becomes disabled, while all the driving force needed by the generator is supplied by the synchronous motor. In the event the entire electric system is disabled, a switch connects the load directly to the utility source.

Alarm device for continually indicating the state of air pressure in a plurality of tires

Abstract: An alarm device for informing reduction of pneumatic pressure of tires comprises a group of oscillators each consisting of an oscillator circuit, an electric power supply source thereof, a switch for closing an electric power supply circuit when the internal pressure of the tire is lowered to less than a prescribed value and radiation antenna, a group of receiver tuning circuits having a receiver antenna, a sweep generator, a comparison circuit for generating the gate control signal, a gate circuit for sequentially gating the output of a ratio detection circuit, pulse noise elimination circuits consisting of monostable circuits and smoothing filters, comparators for comparing the smoothed DC signal with reference signals which discriminate the operation of an oscillator, and alarm devices for generating alarm information.

Short-circuit protection circuit

Abstract: A short-circuit protection circuit for use in an arrangement in which a load is connected to a source of electrical power by way of switch, operates to open the switch only when a true short circuit condition exists, the circuit discrminating between a true short circuit condition and short duration high current surges caused, for example, by bouncing of the contacts of the switch or transient characteristics of the load