Showing papers on "Electric power published in 1981"

Applying Power System Stabilizers Part I: General Concepts

Abstract: The general concepts associated with applying power system stabilizers utilizing shaft speed, ac bus frequency, and electrical power inputs are developed in this first part of a three-part paper. This lays the foundation for discussion of the tuning concepts and practical aspects of stabilizer application in Parts II and III. The characteristics of the "plant" through which the power system stabilizer must operate are discussed and the implications upon stabilizer tuning and performance are noted. A general approach for analyzing stabilizers utilizing an arbitrary input signal is described and applied to the frequency and electrical power input signals.

Optimum Size and Location of Shunt Capacitors for Reduction of Losses on Distribution Feeders

Abstract: New generalized procedures are developed for optimizing the net savings associated with reduction of power and energy losses through shunt capacitor placement on primary distribution feeders. These procedures are applied to realistic problems to facilitate their immediate use by the electric utility distribution system designer. It is shown that a basic principle, called here "The Equal Area Criterion", offers significant computational and physical insight into numerous problems outside the bounds of studies previously reported and widely accepted in industry

Device for conversion of light power to electric power

Abstract: This invention relates to a high efficiency device for the direct conversion of light power to electrical power. Present photocells for accomplishing this purpose are well known to the art and have a theoretical efficiency not exceeding about 20%. In practice, realization of efficiency of about 10% has been achieved, but ultimately the theoretical limitation is an upper limit which cannot be exceeded by devices utilizing known construction. The present device differs from the prior art devices in that it utilizes a plurality of dipole antennae for absorbing light photons, employing an alternating electrical field of said photons to cause electrons in the dipole antenna to resonate therewith and absorb electrical power therefrom, with means for rectifying said AC power to DC, said DC being accumulated on conducting busbars from the plurality of antennae and associated rectifying circuits.

Wind power electrical generator system

Abstract: A wind power electrical generator system having improved efficiency including a wind mill which activates an air compressor to generate a supply of pressurized air. An air motor activated by the supply of pressurized air drives a generator to produce electrical power. A waste air recovery mechanism, activated by the waste air from the air motor produces rotary energy assisting the wind mill in activating the air compressor.

System Restoration Plan Development for a Metropolitan Electric System

Abstract: The extended duration of recent major power system disturbances have indicated the need for development of system restoration plans (SRP), which would minimize the time required for restoration of service. This paper presents an efficient approach to SRP, from a complete collapse under peak-and light-load conditions, developed at Potomac Electric Power Company (PEPCo). The method is based on: (a) the combined effort of operating personnel and system analysts, (b) the access to data available from the on-line computer facilities, and (c) the use of an interactive load flow program. The SRP development procedure and the results described in this paper are of general interest in that they can be adopted and applied to the other electric systems.

A Power System Stabilixer Using Speed and Electrical Power Inputs-Design and Field Experience

Abstract: Further development of a power system stabilizer based on measurement of unit accelerating power, where the mechanical power component is derived from speed and electrical power signals, is described. Techniques to facilitate the implementation of such a controller are discussed and the ability of this type of stabilizer to remove some of the limitations inherent in other stabilizer designs is demonstrated. The design, testing and commissioning of this stabilizers is covered and field experience with it on large fossil-fired and nuclear units is documented.

Computer-aided dispatch for electric power systems

Abstract: This paper provides a review of the subject of electric power dispatching. In Section I we show where dispatching fits into the hierarchy of power system operating and planning problems. Section II provides an overview of the issues, concerns and practices of dispatching. Sections III-V are devoted to the algorithmic aspects of dispatching. Finally, in Section VI we highlight the conclusions reached in the proceeding sections and identify a number of research needs.

Microprocessor based energy consumption meter

Abstract: This invention relates to an electricity meter mainly intended for measuring, registration and reading of one or more consumers' electricity power consumption and/or energy consumption. To the electricity meter a display (12) is connected which is adapted to indicate momentary power consumption, present electricity tariff and accumulated energy consumption expressed in monentary units. The electricity meter is an electronic construction and includes a central processing unit (1) with a microprocessor, one sensor(2) intended for detecting of a consumer's power consumption and a number of memory cells (1a-52d) adapted in a predetermined manner to consecutively receive and store information, calculated and transferred by the central processing unit (1). The electricity meter is also adapted to be connected to a read unit (5) by which stored information and electricity tariffs can be transferred to a central computer, located at, for example, an electrical power producer.

Solid state watt-hour meter

Abstract: A watt-hour meter is disclosed which includes: a microprocessor coupled to a solid-state Hall-Effect sensor; an electrically alterable ROM coupled to the microprocessor; a power supply; a power outage timing means using the discharge characteristic of a capacitor; apparatus for supplying a 60 Hz clock signal to the microprocessor; a readout device coupled to the microprocessor to provide an indication of the power consumed; an output on the microprocessor for controlling a circuit breaker; and a switch for overriding the microprocessor controlled circuit breaker. The microprocessor and the electrically alterable ROM are connected and programmed: to sense the time of day as determined from an initial time of day and setting the 60 Hz clock signal; to sense and compute the power used by the consumer; to automatically open the circuit breaker when power demand on the electric power source is high and/or the cost per kilowatt hour is high; to automatically close the circuit breaker when the power demand on the source of electric power is low and/or the cost per kilowatt power is low; and to allow a consumer to override the microprocessor's control of the circuit breaker.

The Effects of Distribution Voltage Reduction on Power and Energy Consumption

Abstract: Voltage reduction is a practice which has long been used by electric power companies during emergencies to reduce peak demand. Since 1973, some have suggested that it can also be an effective energy conservation method. Others disagree. The purposes of this paper are to: 1) present what is known about the effects of voltage reductions on real power, reactive power, and energy, for individual and composite loads; 2) discuss the problems associated with conservation voltage reduction proposals; and 3) suggest promising approaches for further study. Tests were conducted to determine the real and reactive power dependencies on voltage of a three-phase 5 hp induction motor. The following conclusions are derived from the information presented in this paper. 1) Appliances, motors, and feeders generally show initial reductions of power consumption at reduced voltage, but little reliable information concerning energy exists. 2) Because of the lack of hard evidence and the problems associated with conservation voltage reduction programs, it would be premature for any regulatory agency to mandate such programs at the present time.

Induction generator system with switched capacitor control

Abstract: An electric power generator system including a switched capacitor controlled induction generator adapted to provide power at a regulated voltage and frequency. The system is adapted for autonomous operation for delivery of power with unity power factor to an external power grid.

Control of electric power systems

Abstract: commercial and industrial type. It must withstand with reasonable security the capricious forces of nature. In an age of high energy costs it is called upon to transform the prime energy resources into electric form with an optimum overall efficiency. The control functions are obviously many and varied. Some control and decision processes, exemplified by the optimal utilization of the controlled flow of river systems involve dynamics with month-long time constants. Other phenomena, like the transients on the transmission lines following lightning strikes, run their course in a few milliseconds. The slower control processes are normally handled by computer-assisted human operators. The faster control functions are trusted to fully automatic control systems of either open or closed-loop nature. The objective of this article is first to outline briefly the basic functional features of a power system and, secondly, describe some of the more important controls required for its satisfactory operation. Finally some of the more relevant research and development areas are identified and discussed. Fig. 1 shows a one-fine diagram of a section of a larger system. The electric power is produced in the generators. transformed to an appropriate voltage level in the transformers and then via the buses sent out on the transmission fines for final distribution to the loads. Via tie-lines the system is connected to neighboring systems belonging to the same pool. Fig. 1 does not show the low-voltage distribution portion of the system, which contains the majority of the load objects. For most important system studies it is sufficient to use lumped or composite representations of the loads. The load symbols in Fig. 1 are of the latter type. The circuir breakers permit the tripping of faulty components and also sectionalizing of the system. High voltage dc (HVDC) is being used in special cases. However, the vast majority of the world's electric power is being generated, transformed, transmitted and distributed as high voltage ac (HVAC) of the threephase variety. Collectively the generators, transformers, buses, lines and loads constitute the power network or grid.

Generalized theory of electric power

Abstract: The paper presents the generalized theory of electric power, which makes it possible to estimate the operation of complex electric circuits. Use has been made of the correlation analysis and new definitions have been found for various kinds of power occurring in such systems. It has been shown that both the active and the reactive power depend on the voltage-current correlation of the system. A new definition has been found for the distortion power, together with the condition which leads to its minimization.

Automatic temperature control device for an electric appliance such as an electric blanket

Abstract: The automatic temperature control device for an electric appliance such as an electric blanket comprises a heater element, a sensor made of a thermosensitive material having an impedance, which changes as the temperature varies, for detecting the temperature of the heater element, switching means for regulating the supply of electric power to the heater element, and a plurality of electric circuits for driving the switching means in response to the output signal from the sensor. The plurality of electric circuits function to prevent the sensor from being polarized and to detect a temperature signal by applying thereto an alternating current, to detect a failure occurring in the electric circuits in synchronism with zero-crossing pulses, and to detect a failure occurring in the switching means, thereby assuring a safe operation of the automatic temperature control device against the occurrence of any failure.

Method for controlling an air conditioning system

Abstract: In a method for controlling an air conditioning system including a frequency-variable power source device for providing an AC electric power of a variable frequency, and a compressor driven by the AC electric power, the air conditioning power of the conditioning system being dependent on the frequency of the AC electric power, the temperature of the air to be conditioned is detected; and a frequency set value is determined in accordance with a deviation of the detected temperature with reference to a set temperature. For determining the frequency set value, a plurality of temperature deviation zones are defined; the frequency set value is changed when the deviation transits from one of the zones to another; and the frequency set value is also changed when the deviation continues to be within one of the zones of a relatively great deviation over a predetermined length of time.

Generating system utilizing multiple-stage small temperature differential heat-powered pumps

Abstract: A generating system is disclosed for converting the flow of a first liquid to electric power comprising a plurality of multiple-stage small temperature differential heat-powered pumps, a liquid heater operable to heat a second liquid to a fixed hot temperature, a liquid cooler operable to cool a third liquid to a fixed cool temperature, a hydraulic-to-mechanical power conversion device which is operative to convert the flow of the first liquid to mechanical power with its input connected to the output of the plurality of multiple-stage small temperature differential heat-powered pumps and its output connected to the input of the plurality of multiple-stage small temperature differential heat-powered pumps, and a mechanical-to-electrical power conversion device to produce electric power.

A.C. Electricity power supply system and methods of and apparatus for load control thereon

Abstract: For safeguarding an alternating current electrical power supply system against a blackout due to overloading, particularly on a system which is not strongly interconnected, each consumer (20, 21, 22) is provided with means sensing when the supply frequency falls below a predetermined frequency, these means controlling switching devices (36) for interrupting the power to at least part of the load taken by each consumer. The sensing means conveniently comprises a control unit (50) responsive to the loss in phase lock of an oscillator (40) locked to the incoming supply frequency and forming for example part of an energy metering device. Provision is made for automatic restoration of the supply to loads when the frequency increases to another predetermined value.

Differential fault current protection of a multiprocessor controlled electric power generating system

Abstract: The invention relates to a fault current detection, isolation and clearing system for use in an integrated power generating and distribution arrangement having multiple generators electrically connected to loads and to a distribution bus through circuit breakers. The system includes a power control logic unit and circuit breaker condition detection units which have their outputs electrically coupled to the power control logic unit. Fault current detection circuits are coupled to the electrical connections of the generating and distribution arrangement and have outputs electrically coupled to the power control logic unit. The power control logic unit has an output which is controllingly electrically connected to the circuit breakers to control the circuit breakers and clear faults from the generating and distribution arrangement as a function of circuit breaker conditions and fault currents detected.

Potential Dynamic Impacts of Wind Turbines on Utility Systems

Abstract: This paper presents the results of an initial assessment of potential wind power generation dynamic impacts on utility systems from a global utility perspective performed for the Electric Power Research Institute. Dynamic study of minute-to-minute ramping, frequency excursions, and short-term transient stability was performed using the isolated Hawaiian Electric Company (HECO) system as an illustrative example. Potential minute-to-minute ramping requirements imposed on conventional generation units of two interconnected utilities, Kansas Gas and Electric (KG&E) and Public Service Company of Colorado (PSCo) were investigated, using interconnected utility operating criteria.

Emergency ventilation control apparatus for animal confinement house

Abstract: An apparatus responsive to electric power failure for opening curtains or doors normally covering ventilation openings in a confinement house of the type used for raising poultry and livestock is disclosed. An electromagnet (59) is provided which is energized by the electric power supply (41) to the house (10) and is de-energized upon failure of the electric power supply (41). A pivoted metal strip (61) is normally in contact with the magnet (59) and is interconnected by means of a cord (66) with the winch (25) which is used to raise and lower the curtains (16). When the electric power (41) fails and the electromagnet (59) is de-energized, the cord (66) releases, and allows the curtains (16) to fall under their own weight. A capacitor (78) prevents de-energization of the magnet (59) when momentary power failures occur.

Homeostatic control : the utilitycustomer marketplace for electric power

Abstract: A load management system is proposed in which the electric utility customer controls his on-site power demand to coincide with the lowest possible cost of power generation. Called Homeostatic Control, this method is founded on feedback between the customer and the utility and on customer independence. The utility has no control beyond the customer's meter. Computers located at the customer's site are continuously fed data on weather conditions, utility generating costs, and demand requirements for space conditioning, lighting, and appliances. The customer then directs the computer to schedule and control the power allotted for these functions. On-site generation by the customer can be incorporated in the system. It is argued that homeostatic control is technically feasible, that the level of control equipment sophistication can be adapted to the benefits received by the customer, that such a system would encourage the use of customer-site energy storage and energy conservation equipment, and that it represents a realistic method for allowing the customer to decide how he will use electric power during an era of increasing costs for power generation. (LCL)

Electrical power packs and charging devices

Abstract: A power pack (1) for use as an alternative to non-rechargeable batteries (3) in a toy (2) comprises a plurality of series connected rechargeable cells (13) accommodated within a casing (7) which is sealed permanently against removal of the cells and carries output terminals (11A-11C) arranged to cooperate with the power input terminals (6A-6D) of the toy when the power pack is inserted in place of the cells and with the contact terminals (25) of a recharging device (18) when the power pack is engaged with this device for recharging the cells. The power pack casing is shaped to cooperate with the toy (2) and recharging device so that it will engage with each in only one predetermined position.

Plant for producing electrical power from a watercourse and turbine assembly for such a plant.

Abstract: not available for EP0034605Abstract of corresponding document: DE2933907Plant for producing electric power from a watercourse is comprised of immersed turbines. The turbines known of this type are anchored in the bed of the river by complex and expensive arrangements. Such arrangements are superfluous if the turbine assembly (1) comprised of one or a plurality of turbines immersed and forming a closed unit is anchored while floating freely on the water. Cables (2) are anchored to pillars (3), buoys, rafts or pontoons. It is also possible to anchor the turbine assembly directly to the raft (9) or pontoon. To increase the floating capacity, the turbine assembly is provided with floating chambers.

Apparatus for identifying defective electric power distribution capacitors

Abstract: An apparatus for determining the operating condition of capacitors of the type used for power factor correction on electric distribution systems is assembled in two sections. A first power supply device supplies an alternating electric current to a de-energized capacitor without removing it from its installed position and a second power measurement device, utilizing a split-core Hall-device, measures the magnitude of the electric current entering the capacitor being tested.

Control system for electric automobile heating apparatus

Abstract: An electric heating apparatus for heating the passenger compartment of a motor vehicle, such as an automobile, having an internal combustion engine driving an electric power generator for charging a battery supplying power to electrical equipment on the vehicle includes a control system permitting actuation of the apparatus only when the engine reaches a predetermined rotational speed above which the generator is able to generate power. The air-fuel mixture supplied to the engine is regulated by a rotational speed control means in accordance with a control signal produced by a control circuit responsive to a temperature sensor detecting that the engine temperature is below a predetermined level and a voltage sensor detecting that the voltage produced at the neutral terminal of the power generator is higher than a predetermined value to increase the rotational speed of the engine and thereby the power generated by the power generator. A power supply switch responsive to the control signal is energized to cause power to be supplied to the electric heating element of a warm air generator for supplying heat to the passenger compartment until such time as the engine temperature rises above the predetermined level, the detected voltage drops below the predetermined value or the system is manually turned off by operation of the ignition switch or a system operating switch. The control system prevents over-discharge of the vehicle battery.

Plasma etching device

Abstract: PURPOSE: To prevent damaging upon elements and the change in properties of resist and to improve treating capacity in a counter electrode type plasma etching device by connecting two high frequency electric power sources of different frequencies. CONSTITUTION: The inside of an etching device is evacuated and a reactive gas is introduced therein and is maintained under prescribed pressure. High frequency electric power of a high frequency is applied from a high frequency electric power source 7 to an anode electrode 3, so that plasma is generated between the electrode 3 and a cathode electrode 2. Similarly, high frequency electric power of the frequency lower than that of the power source 8 is applied to the electrode 2 or the electrode 3 so that plasma is generated. At this time the plasma density is increased or decreased by increasing or decreasing the high frequency electric power to be applied to the electrode 2, thereby changing the ion energy impinging upon the object to be etched. By this mechanism, a high etching rate is obtained and the treating capacity of etching is improved. COPYRIGHT: (C)1982,JPO&Japio

General design aspects of a 300 MVA superconducting generator for utility application

Abstract: Development of a 300 MVA electric utility generator with superconducting field winding has been initiated by the Westinghouse Electric Corporation under joint sponsorship with the Electric Power Research Institute. This generator is scheduled to be on line in a U. S. utility by mid-1984 for an extended test and demonstration period. A brief review of the configuration and design features of the 300 MVA machine is given, the emphasis is then shifted to a discussion of the utility environment and its impact on the design of the generator. Specially, system transient events such as faults are covered in terms of their mechanical and thermal consequences for the designer. Finally, the analytical tools and models that are being developed for the present program are discussed.

Towards a high‐temperature solar electric converter

Abstract: The results of an experimental and theoretical study aimed at developing a novel high‐temperature solar electric converter are reported. The converter concept is based on the use of an alkali plasma to serve as both an efficient high‐temperature collector of solar radiation as well as the working fluid for a high‐temperature working cycle. The envisioned working cycle is a simple magnetohydrodynamic Rankine cycle. The motivation for developing this type of solar electric converter is based primarily on the cost and weight reduction premiums for operating a space solar electric generator at the maximum possible temperature. We report on the construction of a theoretical model for coupling sunlight into a cesium plasma and on the experimental demonstration of cesium heating with a solar simulator that is in good agreement with the theory.

Power generating system

Abstract: A power generating system for supplying electrical power to an external electrical power demand load including a vertically oriented centerbody adapted to adsorb radiant solar energy; an annular enclosure around the centerbody defining a vertically extending air passage between the centerbody and the enclosure capable of transmitting radiant solar energy therethrough toward the centerbody; mirror means for directing solar radiant energy through the enclosure onto the centerbody to heat it so that the air in the air passage is heated to induce an airflow through the passage; a rotor rotatably mounted at the lower end of the air passage with a plurality of vanes operatively associated with the air passing into the lower end of the air passage to cause the rotor to rotate; electrical power generating means operatively connected to the rotor so that rotation of the rotor causes the generating means to generate electrical power for the external electrical power demand load; and fuel synthesis means selectively connected to the output of the power generating means to generate and store hydrogen when the output of the power generating means exceeds the external power demand load and to supply hydrogen from storage for burning in the air passage to heat the air therein when the output from the power generating means is less than the external power demand load.