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In practical power systems, the fault current sensed by the relay depends on location of the fault and network topological changes. Fault current sensed by the relay for near end fault is greater than that for a far end fault. In meshed distribution systems with Distribution Generation (DG), the fault currents are fed from both ends of the line and consequently the currents sensed by the relays at...
This article describes a fault location method, developed within our laboratory, which uses the physical parameters of an electrical line to estimate the series arc fault distance in an experimental short indoor power line. The method estimates currents at several hypothetical fault points on the line, using recorded data at both ends of the indoor power line, by looking for a current difference minimization...
This paper presents a method of fault diagnosis in a power distribution network. A segment of a 88 kV power distribution network is modelled in Digsilent Power Factory. Various types of fault cases are obtained through an Electromagnetic Transient study on the model. Discrete wavelet transform (DWT) is used to extract features from transient fault currents measured at the source terminal of the network...
This paper presents an application of the Electro-magnetic Time Reversal (EMTR) in changing media to identify the fault location along a single-conductor transmission line. It is shown that the time-reversed quantities exhibit a property, called Mirrored Minimum Energy, that permits the identification of the fault location along the line. Specifically, the fault location can be determined by analyzing...
In this paper a single-ended travelling wave-based fault location algorithm is presented with reference to HV (60 kV) overhead unearthed operated lines:the time-frequency characteristics of the travelling wave signal are processed by utilising the phase to modal transformation and the continuous wavelet one. The frequency components of the processed signals are used for the travelling wave speed calculation...
Transmission system serves as a crucial link between generating stations and consumers. Early detection and accurate location of faults on a transmission line is essential to prevent the occurrence of blackouts. Also monitoring of real-time states of power system during faults will enhance the situational awareness for power system operators. Wide Area Measurement and Protection Systems (WAMPS) based...
This paper is concerned about fault location in power systems using a sparse set of PMU measurements and proposes an improvement to a previously presented solution [1]. This fault location method, associated with sparse optimization and wide-area synchronized phasor measurements, provides an accurate fault location tool independent of fault type or fault resistance. However, this method assumes the...
Evaluating workpiece quality of electrical discharge machining (EDM) process is challenging users when trying to extract features from the stochastic and time-consuming process. This study proposes an intelligent sensing unit for EDM (ISU-EDM) to extract key machining features for predicting the roughness of workpieces. In machining, the ISU-EDM can synchronously sample the waveforms of discharge...
Updating current swell for each feeder is one of stage of fault localization considering impedance based method. Estimation formula was adopted based on impedance line and load value. This paper investigate the impact of single and paralel impedance load to the accuracy of current swell estimation in the each feeder. Three Phase to ground fault (LLLGF) was simulated using the PSCAD simulation program...
A prototype of the framework AutoFault, which automatically constructs fault-injection attacks for hardware realizations of ciphers, is presented. AutoFault can be used to quickly evaluate the resistance of security-critical hardware blocks to fault attacks and the adequacy of implemented countermeasures. The framework takes as inputs solely the circuit description of the cipher and the fault(s) and...
In the present research, a methodology was developed to determine the faults location in transmission lines, a hybrid model was developed that combines the advantages of the Relief algorithm with those of the Wavelet Transform in the presence of a contingency. For this, the information of the voltage and current synchrophasors obtained from the PMUs deployed in the power electrical system is used...
The single terminal fault location method is based on the wavelet modulus maximum to obtain the time difference that the fault traveling wave reach the same measuring point, which can calculate the fault distance, but the error of the actual results is relatively large. In this paper, a traveling wave fault location method based on Wavelet and improved singular value difference spectrum is proposed...
Currently, the main methods of fault location are based on traveling waves. In the presence of noise, the performance of such methods tends to decrease. Therefore, this paper presents a performance evaluation of four noise reduction morphological filters applied to the fault location methods for HVDC lines. In the analyses, different morphological filter configurations are adopted, as well as various...
This paper discusses solid-state fault current limiting technologies. Both solid-state fault current limiters and converters can quickly limit DC fault currents and permit other protective devices to perform appropriate fault interruption and/or isolation. Different system protection strategies using solid-state fault current limiters and converters are presented and analyzed. The advantages and disadvantages...
The experimental studies of point-like discharge sustained by radiation of terahertz band gyrotrons aimed to development of source of extreme ultraviolet light are described. Plasma was created in the nonuniform gas jet. The plasma density was measured from the Stark broadening of the line Ha. The radiation in the vacuum ultraviolet region was investigated using a calibrated PMT and filters, the radiation...
A comparison of bending speed and experimental setups using 3-point or 4-point bending for introduction of flex cracks into multilayer ceramic capacitors (MLCCs) in a controlled manner is presented. The impact of bending speed and corresponding strain rates on the formed flex cracks detected by X-ray imaging and optical microscopy images of cross-sectioned MLCCs are examined. Furthermore, the critical...
Rotor winding interturn short circuit is the main fault of synchronous electric machines, it is of great significance to the safe and stable operation of the machine to discover and handle the fault timely. In view of this, the fault positioning method of rotor turn-to-turn short circuit of synchronous machines was studied. The mathematic expression of exciting magnetomotive force (e-m.m.f.), electromotiveforce...
This paper presents the design for a dc circuit breaker based on the coupled-inductor for use in dc grid protection. The breaker acts autonomously as a result of the fault current path. The exact step change in current required to open the breaker can be adjusted in the design by selecting an appropriate turns ratio for the coupled-inductor. A simulation is run for a zonal dc grid to demonstrate the...
Results of the experimental investigation of the gas discharge in the beams of the powerful terahertz radiation are presented. Study of the self-sustained and initiated discharges by using the radiation of pulsed gyrotron (developed in IAP RAS) with frequency value of 40kW@0.67 THz (20 μs pulse length) was made in the wide range of pressures (3·10−3–1500 Torr) in different gases (argon, krypton, xenon,...
At present there is no standardized grounding method for medium voltage direct current (MVDC) shipboard power distribution systems. This paper introduces a method for selection of a maritime MVDC grounding scheme that considers technical acceptability, maintainability, reliability, safety, and feasibility. Several candidate grounding approaches and the results of the selection process are presented...
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