Showing papers on "Power-system protection published in 1980"
DOI•
01 Jul 1980TL;DR: In this paper, the basis of a new ultra-high-speed transmission line protection scheme is described, where analogue processing is performed using charge-coupled devices to extract the fault or superimposed components impressed on a power system following a disturbance.
Abstract: The basis of a new ultra-high-speed transmission-line protection scheme is described. Analogue processing is performed using charge-coupled devices to extract the fault or superimposed components impressed on a power system following a disturbance. The new arrangement is designed for use in conjunction with carrier blocking communication equipment and tripping times of typically 2 to 4 ms are shown to be feasible for most faults. The results of an cxtensive series of laboratory tests are given and the paper concludes with a consideration of the performance of the new scheme following very high resistance single phase-to-earth faults.
78 citations
23 Jun 1980
TL;DR: This paper presents the basic concepts of a new fault diagnosis technique which has the following features: is applicable to both single and multiple faults, does not require fault enumeration, and can identify faults which prevent initialization.
Abstract: This paper presents the basic concepts of a new fault diagnosis technique which has the following features: 1) is applicable to both single and multiple faults, 2) does not require fault enumeration, 3) can identify faults which prevent initialization, 4) can indicate the presence of nonstuck faults in the D.U.T., 5) can identify fault-free lines in the D.U.T. Our technique, referred to as effect-cause analysis, does not require a fault dictionary and it is not based on comparing the obtained response of the D.U.T. with the expected response, which is not assumed to be known. Effect-cause analysis directly processes the actual response of the D.U.T. to the applied test (the effect) to determine the possible fault situations (the causes) which can generate that response.
67 citations
TL;DR: In this article, a reliability model of a system and its associated protection system is described and a measure of system unreadiness is defined and suitable expressions are derived for this index and the mean duration of undetected faults.
Abstract: A reliability model of a system and its associated protection system is described. The protection system detects the presence of faults and isolates the faulted equipment so as to prevent damage and minimize the effect of the faulted equipment on the operation of the rest of the system. If the protection system does not respond and the faulted component is not disconnected, a backup protection system comes into operation. The backup operation isolates a larger segment and disturbs the system more than if the designated protection system had responded appropriately. An example is the protective relay systems for electric power transmission and distribution systems. A measure of system unreadiness is defined and suitable expressions are derived for this index and the mean duration of undetected faults. The unreadiness probability is sensitive not only to the failure rate of the protection system but also to the failure rate of the system, the pdf of interval between inspections and its mean value. The unreadiness probability estimated from a given system cannot be used for another system having a similar protection system. The protection system failure rate can, however, be used to obtain the unreadiness probability.
66 citations
TL;DR: In this article, a comprehensive underfrequency protection program was developed for the Southern electric system in which digital computer simulations were used to optimize a system wide load shed program and to verify its coordination with a steam turbine-generator under-frequency protection scheme.
Abstract: A system disturbance or operating abnormality may leave a power system with a generation deficiency, which, if uncorrected, can result in an extensive power outage. The possibility of such disturbances has led to increased interest in the application of automatic underfrequency protection schemes to restore load/generation balance and to prevent equipment damage. This paper presents a comprehensive underfrequency protection program recently developed for the Southern electric system in which digital computer simulations were used to optimize a system- wide load shed program and to verify its coordination with a steam turbine-generator underfrequency protection scheme.
45 citations
TL;DR: In this article, it is shown that coordination is possible between low clamping-voltage devices having limited energy capability and high-clamping voltage devices having high energy capability, as well as additional experimental results on surge propagation.
Abstract: Surge protectors can be installed in low-voltage ac power systems to limit overvoltages imposed on sensitive loads. Available devices offer a range of voltage-clamping levels and energy-handling capability, with the usual economic trade-off limitations. Coordination is possible between low- clamping-voltage devices having limited energy capability and high-clamping- voltage devices having high energy capability. The paper gives two examples of coordination, as well as additional experimental results on surge propagation.
33 citations
TL;DR: The design of a computer based impedance relay is discussed and a multi-function approach is proposed which incorporates metering, fault arcniving and frequency monitoring.
Abstract: The design of a computer based impedance relay is discussed and a multi-function approach is proposed which incorporates metering, fault arcniving and frequency monitoring. Results from a prototype installation are presented.
20 citations
TL;DR: In this article, the authors describe a digital system using thirteen microprocessors which performs all the control and protection functions at a substation using three data channel structure to manage all the signal flows for controlling and protection.
Abstract: The progress of microprocessors has been so remarkable in recent years that the application of modern digital data processing techniques can solve many problems in power system control and protection field. This paper describes a digital system using thirteen microprocessors which performs all the control and protective functions at a substation. The fundamental concept of this system is Three Data Channel Structure to manage all the signal flows for control and protection. This system has been installed at a substation since December 1977 and the field test has demonstrated its feasibility for commercial application with valuable field experiences.
14 citations
TL;DR: In this paper, discussion is carried about an CRT interactive computation system of distance relay setting for back-up protection.
Abstract: In this paper, discussion is carried about an CRT interactive computation system of distance relay setting for back-up protection.
13 citations
TL;DR: In this paper, an index is presented to evaluate the system usefulness using the cost effectiveness for fault protection in a system of given bank kVA, and the index is estimated on four different system structures of control centers, including one which utilizes Permanent Power Fuses (PPF).
Abstract: The increase in electric power consumption in industry has led to the development of modern distribution systems such as control centers having high kVA ratings and high prospective fault current. In such a situation, the improvement of the system usefulness such as reliability and cost effectiveness is the essential requirement. An index is presented to evaluate the system usefulness using the cost effectiveness for fault protection in a system of given bank kVA. The index is estimated on four different system structures of control centers, including one which utilizes Permanent Power Fuses (PPF). It is presented that the PPF combined with molded case circuit breaker in main circuit effectively improves the cost effectiveness in control centers with high fault current. Operating principles of the PPF and the control center utilizing the PPF are briefly outlined.
12 citations
TL;DR: In this article, an intrastation optical fiber transmission system and optical components were developed for electrical power system control and protection, composed of light emitting diodes, step-index multimode fibers and PIN-photodiodes.
Abstract: An intrastation optical-fiber transmission system and optical components were developed for electrical power system control and protection. This system is composed of light emitting diodes, step-index multimode fibers and PIN-photodiodes.
TL;DR: In this article, the authors proposed a fault-current limitation scheme for the first loop by diverting it to ground, then isolating the ground switch and inserting a reactor into the line to limit subsequent fault current.
Abstract: This paper is intended to bring to the attention of the electric power industry a practical means for achieving the benefits of fault-current limitation. This proposed scheme circumvents fundamental problems which have thus far prevented the realization of adequate, reliable fault limiters at high power voltage and current ratings. Current limitation is achieved by the simultaneous actuation of two interrupters and a grounding switch. This single action limits the fault current for the first loop by diverting it to ground, then isolates the ground switch and inserts a reactor into the line to limit subsequent fault current. Employing state-of-the-art technology, this scheme can accommodate the practical range of distribution and transmission voltages and currents. It is shown that because of the inherent characteristics of this device operating in a power system, there is virtually no significant increase in the severity of duty imposed on source side transformers.
TL;DR: In this paper, the implications of FCL reliability upon the design and application of fault current limiters are examined, and the authors examine the following important questions: 1) Can devices which are designed to meet present functional specificationis for faultcurrent limiters be made compatible with the implicit need for reliability and economy? 2) Sinice no device will ever be fully reliable, what are the consequenices of failure, anld what constitutes reasonable backup protectioni? 3) Cain the quest for the FCL be met better in a manner more consistent with the essential needs for economy
Abstract: This paper is principally concerned with the implications of FCL reliability upon the design and application of fault current limiters. The paper examines the following important questions: I) Can devices which are designed to meet present functional specificationis for fault current limiters be made compatible witlh the implicit need for reliability and economy? 2) Sinice no device will ever be fully reliable, what are the consequenices of FCL failure, anld what constitutes reasonable backup protectioni? 3) Cain the nieeds whlichi have spawned the quest for the FCL be met better in a manner more consistent with the essential needs for economy and reliability by modifying the functional specifications? t 4) For puirposes of backup protection, would a limiter which responds only after the first current loop has been allowed to pass be of any worth? 5) Are there any significant improvements or benefits in the tolerance of apparatus to momentary currents if severe fault currents are limited to a single current loop?
TL;DR: In this paper, eight aspects of unit protection for which new or modified protection is desirable are discussed, and Conventional protective relay systems should be supplemented with monitoring systems to detect incipient fault conditions.
Abstract: Recent operating experience has prompted a reappraisal of generating unit protection to insure that damage from all potential hazards will be minimized. Eight aspects of unit protection for which new or modified protection is desirable are discussed. Conventional protective relay systems should be supplemented with monitoring systems to detect incipient fault conditions.
TL;DR: In this article, a successful application of microprocessor and fiber optic technologies to the monitoring and protection of ZnO nonlinear bypass resistors has been described, and two systems have been implemented and have undergone extensive fault testing.
Abstract: The result of this development effort is the successful application of microprocessor and fiber optic technologies to the monitoring and protection of ZnO nonlinear bypass resistors. Two systems have been implemented and have undergone extensive fault testing. Both systems have operated correctly and have exhibited excellent noise and transient surpression. The developed monitoring and protection algorithm is unique, demonstrating the versatility of the microprocessor technology as applied to power system monitoring and protection problems. The fiber optic analog channel developed for this application is unique, exhibiting a high level of accuracy, and providing excellent electrical isolation between an active power system and sensitive digital systems.
TL;DR: In this paper, the state of the art of digital relaying, including microprocessors and central computers and their expected advantages, is outlined, and trends in power system design and the requirements these impose on protective relaying are discussed.
01 Nov 1980
TL;DR: In this paper, the authors examine methods of improving the transient response of the industrial system under various external and internal fault conditions, with a view to improving the security of supplies to important drives and auxiliaries.
Abstract: This paper is based on recent electrical system studies carried out on an Imperial Chemical Industries (ICI) plant located in Scotland, which derives its power supplies from both in-house generators and grid interconnection. The objective was to examine methods of improving the transient response of the industrial system under various external and internal fault conditions, with a view to improving the security of supplies to important drives and auxiliaries. High levels of plant security and enhanced synchronous-generator stabffity are normally associated with multiple-grid and in-house distribution feeders, with corresponding low values of impedance between the supply sources and motor drives. However, this paper examines all aspects of system behaviour during fault conditions and concludes that, in this instance, an improvement to overall transient performance is achieved by increasing grid feeder reactance immediately after fault inception. In the case of external faults developing on the interconnected grid, computer-aided studies show the advantage of rapidly switching out one of the grid transformer feeders. Similarly, in the event of selected internal faults occurring, study results show the improvement achieved by rapidly opening normally closed ring mains, thereby doubling the effective ring feeder reactance.
01 Jan 1980
TL;DR: In this paper, the authors consider the complete system protection or selectivity requirements, accepting the compromises necessary to achieve these contradictory goals, and propose a set of compromises that can achieve both full-range through-fault protection and complete system selectivity.
Abstract: Primary overcurrent devices usually cannot provide full-range through-fault protection and complete system selectivity. The protection engineer must consider the complete system protection or selectivity requirements, accepting the compromises necessary to achieve these contradictory goals. 6 figures.
TL;DR: Voluntary consensus standards refer to those documents developed under the ANSI program, and Guides refer to documents in which alternative approaches to good practice are suggested, but no clear-cut recommendations are made.
Abstract: Present society uses an increasing number of processes, fabricated products and services to accomplish its purposes and satisfy its needs. In order to improve the safety, reliability and performance of these processes, products and services and to facilitate communication regarding them, many voluntary, consensus standards documents are developed and applied. Voluntary consensus standards refer to those documents developed under the American iJational Standards Institute (ANSI) program. The principal types of documents are: Codes -Systems or collections of regulations or systematic bodies of law relating to particular subjects and especially those given statutory force. Standards -Documents witlh mandatory requirements. They are generally characterized by the use of the verb \"shall.\" Recommended Practices -Documents in which procedures and positions preferred by IEEE are presented. They are generally characterized by the use of the verb \"should.\" Guides -Documents in which alternative approaches to good practice are suggested, but no clear-cut recommendations are made.
TL;DR: The implementation of a digital technique for breaker-fail protection, using rate of rise of current at zero crossings as an indicator of current magnitude is described, using results obtained on a PDP 11/10 computer for single and multiple circuit breaker failure.