Search

This paper proposes a new algorithm for the detection and classification of faults in transmission lines in the presence of distributed generation. The proposed algorithm uses wavelet transform-based detail and approximation coefficients of voltage and current signals over one cycle after fault inception at one end of the transmission line. The line impedance calculated from the ratio of the voltage and current approximation coefficients is fed to the fuzzy inference system to classify faults. The proposed algorithm has been tested successfully in a real-time digital simulator for nonlinear high impedance faults in the presence of wind farm, considering the effects of CT saturation. All types of faults with the variation of pre-fault loading condition, line parameters, line length and source impedance can be correctly classified using the proposed algorithm. [ABSTRACT FROM AUTHOR]

This study aims to develop a new relaying scheme for the complete protection of transmission line based on only voltage data. Fault detection and classification is obtained from the fundamental component of the voltage signal collected from one end of the line. Magnitudes of positive sequence component of voltage signals from both ends of the line have been considered for fault location. As only magnitude of voltage signal is used, the requirement for data synchronization can be avoided, and the error caused by current transformers (CT) is eliminated. Moreover, positive sequence components exist for all types of faults, unlike negative sequence components. Hence, all types of faults can be located. Fuzzy decision approach has been proposed to avoid computationally expensive training of expert systems. The proposed scheme has been tested for different dynamic situations in MATLAB/Simulink software. The superiority of the scheme has been established by considering coupling capacitor voltage transformer (CCVT) transient error, weak infeed condition, change of transmission voltage level and line loading. [ABSTRACT FROM AUTHOR]

Transmission lines (TL) are exposed to diverse climatic conditions, which make them prone to faults in different phases simultaneously or after a short delay at the same or different locations. These complicated faults can cause failure or mal-operation of the conventional distance protection schemes. This research work presents a solution to identify and classify faults in long TLs under challenging situations. In this algorithm, the fundamental components of voltage and current signals from both ends of the TLs have been considered to evaluate the admittance-based fault index to discriminate the internal fault from the external ones and also to identify the faulty phase. The proposed algorithm has been tested under different dynamic conditions viz. swing condition, close-in fault, presence of series compensator, load angle and source strength variation, etc., to ascertain the robustness and reliability of the algorithm. The significant contribution of this algorithm is that it can accurately detect and classify the complex high impedance faults including evolving and cross-country faults in the transmission systems. [ABSTRACT FROM AUTHOR]

A method for detecting and classifying transmission line faults using cross-correlation and k-Nearest Neighbor (k-NN) has been presented in this article. A unique analogy between the cross-correlogram obtained from the sound phase and a faulty phase in an electric power system, defined here as the fault correlogram, and a normal electrocardiogram (ECG) of human heart has been validated in the proposed work. The proposed method uses synthetic fault data within half cycle of pre-fault and half cycle of post-fault to detect and classify the different faults under varying fault parameters. EMTP/ATP software has been used as the platform to carry out simulation of the power system network followed by signal processing in MATLAB. [ABSTRACT FROM AUTHOR]

• Protective relaying scheme for long transmission line. • Fault detection using positive sequence admittance of two-ends of the line. • Segregation of internal and external fault. • Localization of internal fault using positive sequence fault components. In this paper, a novel integrated approach of protective relaying methodology has been adopted for detecting faults and its location estimation in long transmission line. First, the detection algorithm has been formulated using positive sequence admittance. Subsequently, fault location algorithm has been developed using positive sequence voltage and current phasors. The proposed algorithms have been implemented on a 50 Hz, 400 kV single-circuit transmission line in MATLAB environment. A wide range of diversified and challenging cases have been simulated to test the reliability of this scheme. The results confirm the preciseness of the algorithm, as it can produce accurate results under stressed conditions, viz. high impedance fault (HIF), current transformer (CT) saturation/ capacitive voltage transformer (CVT) transient, close-in faults, swing condition, source strength variation, etc. Moreover, this scheme has also been successfully tested in series-compensated and double-circuit transmission line, which brings out the superiority of this scheme. The comparative analysis with recent protective relaying techniques institutes the potentiality and robustness of the scheme. [ABSTRACT FROM AUTHOR]

• Internal fault detection from phase angles of negative sequence currents. • Phasor diagram of internal fault detection. • Fault location method. 1–26 Double-circuit transmission lines are used in modern power systems to enhance the transmission capability and to improve system reliability and safety. However, the protection of double-circuit lines is a challenging task as the presence of flexible ac transmission system (FACTS) in modern power grid impairs the performance of the conventional distance protection schemes. Moreover, the high impedance faults cannot be detected by relays as they become under-reach. This paper proposes a negative sequence current based scheme for locating faults and identifying faulty circuit/ line in double circuit transmission line compensated by UPFC at one end. In the proposed scheme the current signals are collected from both ends of the line to be protected. Then the negative sequence components of the currents are calculated. The discrimination between internal and external fault is achieved from the phase angles of the negative sequence currents and the fault location is determined from the ratio of the negative sequence currents. Prior knowledge about the type of fault is not required for fault location estimation. Extensive fault simulation studies including high impedance faults have been performed. The scheme is immune to the fault inception angle and fault resistance. [ABSTRACT FROM AUTHOR]

• Protective relaying scheme of UPFC compensated transmission line. • Fault detection using complex power of two end of the line. • Segregation of internal and external fault. • Localization of internal fault using sequence component of voltage and current signal. This study presents an integrated approach for discrimination of internal and external fault, and to obtain pin-point location of the fault in a transmission line connected to unified power flow controller (UPFC). To detect internal fault, this method uses positive sequence component of voltage and current at the local and remote end bus. Fault location estimation technique requires both positive and negative sequence voltage and current components measured from both ends of the line. The performance of the proposed technique has been evaluated by simulating a 400 kV double circuit UPFC compensated transmission line. This technique can detect internal fault under stressed conditions, viz. high impedance fault (HIF), change in source strength, change in load angle, and power swing. Precise fault location has been achieved under wide variation of system and fault parameters. The comparative assessment has been provided to prove the efficacy of the proposed approach. [ABSTRACT FROM AUTHOR]