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Modern power supplies must provide reliable, high-quality power. Therefore, it is important that a transmission line fault be identified accurately, reliably and corrected as soon as possible. A method for classifying fault type based on short time Fourier transform (STFT) is provided in this paper. STFT is a means of signal processing in which a Fourier transform (FT) is performed by setting a window...
This paper proposes a novel transmission line protection scheme based on frequency-domain model identification method with distributed parameter. Integrated impedance is defined by voltages and currents of two end terminals of transmission line. By analyzing the frequency-domain expressions of integrated impedance in internal and external fault states, the amplitude-frequency characteristics of the...
Worldwide analysis of recent wide area cascading failures has shown that very often they were mainly caused by the maloperation of the third zone of a distance protection relay. The load encroachment and power swing phenomena are the two dire problems to solve when dealing with the third zone of distance protection. The vast number of blackouts could have been avoided or the consequences lowered if...
Although there has been a practice of transposition of transmission lines, most of the real life EHV/UHV lines are untransposed. The distance protection of such lines becomes very complicated. With the advent of Global Positioning System (GPS) and Fiber optics technology, current differential protection can be a better choice for such lines. This paper proposes current differential protection scheme...
A transient fault information based IED integrating protection fault location, fault record, measurement and control functions for transmission line is proposed in this paper. IED hardware scheme adopts multiple CPU distributed structure, and includes mainly the following modules: process level communication module, protection module, fault location and record module, measurement and control module,...
The main purpose of this paper is using artificial neural networks (ANNs) in wide area protection of power systems. In fact, implementation of an intelligent protection system of electric network for discrimination between fault and no-fault conditions and also recognition of fault type contains main structure of this paper. Proposed idea has been implemented on IEEE 8-busbars electric network that...
This paper presents a novel protective concept for EHV Three-terminal transmission line, teed circuit. The proposed protective relaying techniques use the fourth sequential overlapping derivative, SOD, concept at all line terminals. The SOD signals represent the transient components initiated due to fault occurrence. Such signals are free of both dc and fundamental components. Two protective relaying...
Transmission line parameter is important for obtaining power network structure, generating power system node admittance matrix or impedance matrix to calculate power flow, calculating short-circuit current, and setting relaying protection devices. But actually, transmission line parameters applied in power system are mostly experience values or offline measuring values provided by manufacturers, they...
Due to the distributed capacitance, the conventional current differential protection has unsatisfying performance. Considering matrix pencil algorithm can accurately analyze the composition of fault transient currents, a novel pilot protection principle using only current data is proposed in this paper to solve the above problem. This principle adopts model recognition concept. Firstly, the theoretical...
This paper presents an accurate fault location algorithm for double-circuit transmission lines with series capacitor compensation at both ends. It has been considered that a fault locator utilizes a communication channel of differential protective relays through it phasors of currents at both line ends are exchanged. Besides the phasors of two-end currents, three-phase voltage measured at a local...
The present transmission systems are rapidly changing principally due to an increasing demand for better utilisation of existing lines resulting in lower transient stability limits, and also due to an increase in the complexity of the networks with small-scale distributed generation being connected into the existing networks. The current protection/fault location techniques are not conducive to such...
For decades, various versions of the Takagi algorithm have been used by microprocessor-based relays for fault location. This system provides accurate fault location, limited by nonhomogeneous infeed, load flow, fault resistance, and series-compensated or parallel lines. With the emphasis placed on reliability in today's power system, the need for improved accuracy in fault location has increased....
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