Journal ArticleDOI
Design of a digital multi-curve time-overcurrent relay
TLDR
An algorithm for implementing a digital time-overcurrent relay on a single 8-b microprocessor with the possibility of processing more than one time-current curve concurrently at low additional cost, thus offering a multioutput relay.Abstract:
An algorithm for implementing a digital time-overcurrent relay on a single 8-b microprocessor is presented. Integer arithmetics is found to provide an adequate overall error performance. The relay responds to the mean value of the fault current, as do most available solid-state overcurrent relays. An extra feature has been devised in this application: the possibility of processing more than one time-current curve concurrently at low additional cost, thus offering a multioutput relay, with each output corresponding to a particular curve. As many as five or six curves, each with its own digitally-adjustable settings and independent output, can be processed simultaneously. A low-cost current-measuring circuit with response time as short as one-half cycle and a broad dynamic range is used. >read more
Citations
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Journal ArticleDOI
IEEE standard inverse-time characteristic equations for overcurrent relays
G. Benmouyal,M. Meisinger,J. Burnworth,W.A. Elmore,K. Freirich,P.A. Kotos,P.R. Leblanc,P.J. Lerley,J.E. McConnell,J. Mizener,J. Pinto de Sa,R. Ramaswami,M.S. Sachdev,W.M. Strang,J.E. Waldron,S. Watansiriroch,S.E. Zocholl +16 more
TL;DR: In this paper, the IEEE standard inverse-time characteristic equations for overcurrent relays were introduced and an analytic representation of typical electromechanical relays operating characteristic curve shapes in order to facilitate coordination when using microprocessor-type relays.
Journal ArticleDOI
Protection system representation in the Electromagnetic Transients Program
TL;DR: This paper concerns the addition of the few critical elements of a protection system to the Electromagnetic Transients Program (EMTP), which is one of the most widely used programs for the simulation of transients in power systems.
Journal ArticleDOI
Fuzzy adaptive setting for time-current-voltage based overcurrent relays in distribution systems
TL;DR: An adaptive protection system based on the Fuzzy Logic for the adjustment of the overcurrent relay’s pick-up currents with instantaneous and current-voltage based inverse-time units is proposed, which resulted in an adaptive method that presented good performance by automatically following changes on the system operation condition and increased the sensitivity of theOvercurrent protection.
Proceedings ArticleDOI
Testing dynamic characteristics of overcurrent relays
G. Benmouyal,S.E. Zocholl +1 more
TL;DR: In this paper, the authors discuss the correlation between the dynamic tests of induction relays and the proposed standard equations for reset and trip characteristics of microprocessor-based relays based on the physics of inductive relays.
Journal ArticleDOI
Some aspects of the digital implementation of protection time functions
TL;DR: In this paper, a basic model for implementing time functions is reviewed and the factors affecting coordination when using relays representing different technologies are analyzed, and a simple test based on a mathematical expression is presented as a means of assessing the dynamic performance of a relay with respect to varying input signals.
References
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Journal ArticleDOI
Digital Programmable Time-Parameter Relay Offers Versatility and Accuracy
E. O. Schweitzer,Antenor Aliaga +1 more
TL;DR: In this article, the authors have developed, implemented, and tested an improved time-parameter relay, which is suitable for all time-overcurrent-li- applications, and also suitable for any time-parmeter function.
Journal ArticleDOI
Some aspects of the digital implementation of protection time functions
TL;DR: In this paper, a basic model for implementing time functions is reviewed and the factors affecting coordination when using relays representing different technologies are analyzed, and a simple test based on a mathematical expression is presented as a means of assessing the dynamic performance of a relay with respect to varying input signals.
Journal ArticleDOI
A Log-Tabel Based Algorithm For Implementing Microprocessor Time-Overcurrent Relays
TL;DR: The difficulties that arise in implementing the time-overcurrent relay characteristic on microprocessor systems are due mainly to two factors: data acquisition is usually linear whereas curve scales are logarithmic and the main variable is the normalized fault current.
Journal ArticleDOI
Inverse time overcurrent relays using linear components
H.K. Verma,T.S.M. Rao +1 more
TL;DR: In this article, a method for synthesizing a time-current characteristic curve of overcurrent relays using linear components is presented. But the accuracy of the characteristic curve is not obtained by fitting nonlinearities of components into it, the accuracies with which the characteristic can be produced and repeated are very high.