Showing papers on "Power-system protection published in 1978"
TL;DR: In this article, an examination is presented of the factors that increase the likelihood and frequency of system failure, and an examination of these factors is presented in terms of the number of failures.
Abstract: An examination is presented of the factors that increase the likelihood and frequency of system failure.
57 citations
TL;DR: In this paper, a distributed parameter model of the transmission line is proposed and the fault distance appears as a time delay between two quantities associated with the travelling waves at the measurement site.
Abstract: A method of transmission line protection based on a distributed parameter model of the line is outlined. It is shown that the fault distance appears as a time delay between two quantities associated with the travelling waves at the measurement site. The time delay can be extracted from the fundamental voltage and current waveforms in the presence of superimposed line transients by means of a correlation technique. The proposed method has been tested by numerical simulations and by means of a real-time analog-type computer on a model transmission line and the results were found to be satisfactory. The feasability of a digital computer implementation is briefly discussed.
51 citations
TL;DR: The vertical boundary of this zone of protection is not linear, as has been believed in the past, but is a circular arc, tangent to the ground, of 150ft radius for 99.5 percent protection and 125ft radius of 99.9 percent protection.
Abstract: The nature of the zone of protection of structures from an elevated rod or wire, inadequately defined in the past, can be determined with high reliability using data developed by E.R.Whitehead of the Illinois Institute of Technology under contract from the Edison Electric Institute for the protection of high-voltage electric transmission lines. The vertical boundary of this zone of protection is not linear, as has been believed in the past, but is a circular arc, tangent to the ground, of 150-ft radius for 99.5 percent protection and 125-ft radius for 99.9 percent protection.
50 citations
TL;DR: In this article, a series capacitor protection scheme that limits capacitor overvoltages by inserting a nonlinear resistor in parallel with the capacitor bank during faults is presented, and the concept of operation, prototype installation and field test performance evaluation are discussed.
Abstract: A new series capacitor protection scheme that limits capacitor overvoltages by inserting a nonlinear resistor in parallel with the capacitor bank during faults is presented. The concept of operation, prototype installationad field test performance evaluation are discussed.
17 citations
TL;DR: In this paper, the authors provide timely information on surge attenuation by UD cables; alternate surge protective schemes for UD cable systems; and application of the available analytical tools to solve protection problems.
Abstract: Ongoing research work, funded through EPRI (Electric Power Research Institute) Research Contract RP795-1, is providing timely information on: (1) surge attenuation by UD cables; (2) alternate surge protective schemes for UD cable systems; (3) the application of the available analytical tools to solve protection problems.
10 citations
TL;DR: In this article, the authors survey control techniques that minimize both the occurrence and the duration of blackouts. And they consider circuit breaker configurations at the power station, electrical control for synchronism loss, electrical controls after system separation, line reconnection after fault clearance, turbine controls, and steam supply source controls.
Abstract: Surveys control techniques that minimize both the occurrence and the duration of blackouts. The author considers circuit breaker configurations at the power station, electrical controls for synchronism loss, electrical controls after system separation, line reconnection after fault clearance, turbine controls, and steam-supply source controls.
4 citations
TL;DR: The planning and equipment selection for a central computer or computer complex as mentioned in this paper begins with its intended functions, i.e., the intended functions of the computer and its intended equipment. But this is not always the case.
Abstract: Planning and equipment selection for a central computer or computer complex begins with its intended functions.
3 citations
01 Aug 1978
TL;DR: The squirrel-cage asynchronous generator offers many advantages; for example, high efficiency, a quickly damped short-circuit current, economy, reliability, and sparsity of related apparatus for regulation, control, and protection as discussed by the authors.
Abstract: The squirrel-cage asynchronous generator apparently offers many advantages; for example, high efficiency, a quickly damped short-circuit current, economy, reliability, and sparsity of related apparatus for regulation, control, and protection. It demands a large supply of reactive power, which can only be satisfied by the charging current of the power system with difficulty, because of the conditions to be met. There is, however, no great trouble in solving the problem, and preventing the danger of self-excitation; furthermore, all of the authors who have treated the subject are unanimously optimistic about it. This, together with the fact that the first suggestion to use asynchronous generators dates back to 1893, prompted the author to find out why only small quantities of them, of very small power ratings, have been installed in the world. The reasons are to be found in the phenomena which appear after a short-circuit in the power system, which justify the exclusive use of synchronous generators.
2 citations
TL;DR: A method for computing system reliability indices considering the effect of switching actions that may be taken after a fault to restore service is presented, useful in evaluating alternative sectionalizing schemes and devices.
Abstract: A method for computing system reliability indices considering the effect of switching actions that may be taken after a fault to restore service is presented. This method is useful in evaluating alternative sectionalizing schemes and devices. A method for computing the frequency and duration of overloading events in redundant systems possessing less than fully redundant capacity is also presented. This method is useful in evaluating the cost-reliability trade-offs of capacity reductions in redundant systems such as multitransformer substations or parallel cable circuits.
2 citations
TL;DR: The development of microcomputers has resulted in numerous applications in the areas of power system protection, control, and data acquisition and the combined advantages of low cost and high performance will result in widespread use in power system applications.
2 citations
TL;DR: In this paper, the authors review pipeline pump motor protection from two fundamental viewpoints: first, from the point of view of damage prevention, and then from the view of limiting damage after a fault has occurred.
Abstract: Grounding and protective relaying for large ac squirrel cage induction motors are reviewed, because pipeline pump drive motors would generally be included in this classification. Special problems such as those associated with weak power systems at remote locations are not considered. The approach taken is to review pipeline pump motor protection from two fundamental viewpoints: first, from the point of view of damage prevention, and then, from the point of view of limiting damage after a fault has occurred.
01 Dec 1978
TL;DR: The results of these tests are compared with previously calculated values, and conclusions regarding the accuracy and suitability of the various methods are presented in this article, where the authors describe tests carried out at Amersham 400 kV substation using injected alternating current and other established methods.
Abstract: Fault currents in extra-high-voltage transmission systems have increased in recent years, and in view of the necessity to keep ground potentials to a minimum, greater accuracy and assurance is required in determining the impedance between substations and the general body of earth. The paper describes tests carried out at Amersham 400 kV substation using injected alternating current and other established methods. The results of these tests are compared with previously calculated values, and conclusions regarding the accuracy and suitability of the various methods are presented.
01 Mar 1978
TL;DR: In this article, the authors discuss the problems in the selection of protection equipment, and explain the relevant principles with the aid of a graph in which typical characteristics of a circuit breaker and fuse, and the generator for which these devices have been selected, are plotted.
Abstract: Changes in generator design during recent years have led to machines with inherently higher impedance; consequently, when the generator is subjected to fault conditions such as earth faults or phase-to-phase short circuits in the distribution network, the level of fault current is reduced in relation to the rated current of the generator. These lower levels of fault current make the selection of protection equipment more critical, particularly when the device is required to operate with very little delay after the application of a fault. (When faults are remote from the generator, there will in general be sufficient fault current to operate the protection equipment). The Author, of Newage Engineers Ltd/Stamford Generators, discusses these problems in the selection of protection equipment, and explains the relevant principles with the aid of a graph in which typical characteristics of a circuit breaker and fuse, and of the generator for which these devices have been selected, are plotted. It is shown inter alia that, for early rupturing, the fuse requires fault current well inexcess of that provided by the generator, and may be useless as a protection for it. The circuit breaker (which has magnetic and thermal trips) is shown to have its limitations; these are discussed, together with the need for back-up protection for the generator. The Stamford "C" range Series 3 control system incorporates a circuit which de-excites the generator and thereby provides back-up protection; the advantages of this system are explained. Order from BSRA as No. 49,057.
Patent•
19 Sep 1978
TL;DR: In this article, the authors propose to perform failure detection in transmission line within quite short time, by enabling easy sampling of data having time difference corresponding with transmission line length, which can be used for failure detection.
Abstract: PURPOSE:To perform failure detection in transmission line within quite short time, by enabling easy sampling of data having time difference corresponding with transmission line length.