Topic
Power-system protection
About: Power-system protection is a research topic. Over the lifetime, 6353 publications have been published within this topic receiving 117961 citations.
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TL;DR: In this article, an adaptive distance relaying concept is presented to minimize the required communication, local measurements are used to estimate the entire power system condition and to calculate the appropriate tripping impedance.
Abstract: Because of the zero sequence mutual coupling of parallel transmission circuits, the distance calculation performed by a ground distance relay is incorrect. This error is influenced by the actual power system condition. Although accounted for by using a large safety margin in the zone boundaries, unexpected overreach can still occur and the operation speed is decreased. Adaptive protection offers an approach to compensate for the influence of the variable power system conditions. By adapting the relay settings to the actual power system condition, the relay will respond more accurately to power system faults. The selectivity of the protection system is increased, as is the power system reliability. In this paper, an adaptive distance relaying concept is presented. In order to minimize the required communication, local measurements are used to estimate the entire power system condition. An artificial neural network is used to estimate the actual power system condition and to calculate the appropriate tripping impedance. Application of this concept to the model of the Dutch 380 kV power system has resulted in an enormous increase in relaying accuracy. The relaying error is reduced substantially. Most importantly, the standard deviation, indicating the relay's sensitivity to power system condition variations, is reduced to nearly zero. The zone boundary is kept nearly constant, which facilitates the relay coordination. The selectivity of the entire power system protection system is improved. It is shown that adaptive protection improves the protection system selectivity, and that artificial neural networks can very well be used to estimate the actual power system condition.
57 citations
TL;DR: In this article, the authors proposed a fault detection method for transmission lines using a full-cycle averaging window, where the average value for voltage and current of the faulty phase, in a specific time interval after fault inception is negative for the forward faults and positive for the reverse faults.
Abstract: In this paper, a new protection scheme for transmission lines is presented. The method has some advantages in comparison with conventional line protection schemes. Faster fault detection and instantaneous coverage of almost 100% of the line are the main advantages of the new method. A full-cycle averaging window is used for fault detection. While the power system is in normal operation conditions, this average is approximately equal to zero. As soon as the faulty signals enter the window, the average is changed to a nonzero value. It is shown that the product of this average value for voltage and current of the faulty phase, in a specific time interval after fault inception, is negative for the forward faults and positive for the reverse faults. The fault is detected by communication between the local and the remote relays. Simulation and experimental results show the efficiency of the proposed method in fast detection of line faults in less than a half cycle.
57 citations
TL;DR: In this article, the authors survey efforts worldwide to develop a commercially viable superconducting fault-current limiter, but particularly focus on one project, with which the author is associated, which developed a 2.4 kW, 3 kA prototype.
Abstract: The new high temperature superconductors are well-suited for fault-current limiters, thanks to stable thermal properties and high operating temperatures. This article surveys efforts worldwide to develop a commercially viable superconducting fault-current limiter, but particularly focuses on one project, with which the author is associated, which developed a 2.4 kW, 3 kA prototype.
57 citations
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 new differential scheme is proposed for pilot protection of transmission lines using synchronous voltages and currents of both terminals of the line, which is capable of fast discriminating between the internal and external faults, even in the worst operating conditions.
Abstract: Differential protection is able to provide the most selective protection compared with other protective schemes. In this paper, a new differential scheme is proposed for pilot protection of transmission lines. The concept of differential impedance ( ${\rm Z}_{\rm diff}$ ) is introduced using the synchronous voltages and currents of both terminals of the line. The proposed scheme is capable of fast discriminating between the internal and external faults, even in the worst operating conditions. The dependence on the line capacitive charging current and the source strength are common problems in conventional pilot protection methods which have been removed in the proposed scheme. Moreover, compared with the conventional differential protection, the proposed scheme can exactly determine the fault location. Both computer and experimental simulation studies have been performed to evaluate the proposed scheme. The obtained results approve the high efficiency of the proposed scheme as powerful pilot protection.
57 citations