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This study aims at proposing an original single‐end protection scheme for the compensated transmission line using traveling waves and game theory. To this end, this paper initially investigates the effects of static synchronous compensator (STATCOM) on traveling waves passing through STATCOM installation point. Furthermore, based on the traveling wave theory, it evaluates the impacts of STATCOM's harmonic on conventional protections. A single‐end method will be proposed in the next stage for fault protection on the compensated transmission lines with STATCOM. The extracted traveling waves in this study will be discriminated using the game theory, and discrete wavelet transform will be utilized to process the signals and assess the sensitivity of the proposed scheme considering the extraction techniques of the traveling wave. According to the obtained results, the proposed protection scheme is a reliable and accurate method for all possible faults type on compensated transmission lines at the various locations of the line and with different fault inception angles. [ABSTRACT FROM AUTHOR]

Advances in renewable energy recourses technologies have paved the way for increased utilization of DC grids in modern power systems. In particular, high voltage DC (HVDC) transmission cables are used to harvest offshore energy. Since failure diagnosis and repair of the buried offshore cables under the sea bed involve quite laborious tasks, accurate fault location is of vital importance. This paper proposes a novel fault location method based on the synchronized measurement of conductors and sheaths currents in each terminal without requiring the voltage signal. Unlike the traveling-wave-based methods, the proposed method is developed for multi-terminal HVDC systems without requiring any high precision measurement infrastructure. The proposed method can be implemented for different system topologies as well as fault resistance and fault distance. The fault location method can provide accurate results even if 10 ms time window samples are imported into the proposed algorithm. In addition, accuracy of the fault location using the proposed method is not affected significantly by noisy condition. Different test systems have been simulated to evaluate performance of the proposed method in various scenarios. Obtained results confirm that the proposed practical method can provide the accurate fault location for all different scenarios and conditions. [ABSTRACT FROM AUTHOR]

This paper presents a new algorithm for fault detection and classification in a power transmission line. The fundamental idea of the proposed algorithm is the calculation of the correlation coefficient (CC) between the current signal of each phase of the three‐phase system and its reference value. The following rule makes the decision of detecting and classifying the fault condition: when the system is running under healthy condition, the correlation between the current signal of each phase and its reference value is very strong; when the system is in faulty condition, the correlation between the current signal of each phase and its reference value is low compared to that in the healthy condition. The new algorithm is applied to a power transmission line model established in PSCAD/EMTDC. Different fault circumstances such as different inception times, different fault resistances, and different locations have been verified. Additionally, far‐end faults with high resistance, faults occurring near a terminal, faults considering variable loading angle, and faults in the presence of noise are easily detected by the proposed method. For each possible scenario of fault, the proposed algorithm requires only the three‐phase current measurement of the local measurement unit. The results show satisfactory performance in most cases. © 2018 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [ABSTRACT FROM AUTHOR]

This paper focuses on comparison of fault position schemes for a long transmission line joint with underground cable. To carry out fault location, two hybrid schemes were implemented. One is the impedance method based on modal transformation (MT) and the other one is the intelligent technique based on artificial neural network (ANN). In this paper one cycle of post fault current and voltage signals were collected initially from the transmission line ends for fault analysis purpose. The first method to analyze the fault position comprises of MT technique in which initially pre-processing of the data is done by Clarke's Transformation (CT) and Discrete Fourier Transform (DFT). CT decouples the signal and DFT extracts the phasors. Thereafter the fault location is calculated by Power System distributed line modal and MT concept. The second method focuses on estimation of fault distance by ANN with Wavelet Transform (WT) in which WT is used to extract six statistical features in order to pre-process the raw faulted data. These features are then given to ANN for finding fault position. The enactment of the suggested scheme is verified by testing it under different type of fault position, such as variation of fault resistance, inception angle and type. After extensive simulation, it was found that intelligent scheme i.e ANN-WT schemes are capable of locating the fault more accurately and less sensitive to parameter variation than the impedance method i.e MT-CT-DFT. [ABSTRACT FROM AUTHOR]

We propose a novel method using dual pulse widths to locate the fiber break, which can share the pulse detecting source with the previous proposed passive optical network (PON) monitoring systems. The rectangular detecting pulses with two different pulse widths are sequentially injected into the faulty fiber link to generate corresponding parameters for the established model equations. We also investigate the corresponding variables (i.e., different combinations of dual pulse widths, pulse repetition frequency and accuracy of the power meter) that may affect the performance of the proposed method. The experimental results show that the fiber breakpoint can be located with little error. The simple and low-cost method provides a fault localization functionality for the PON monitoring systems. [ABSTRACT FROM AUTHOR]

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The paper presents a new digital relaying for detection, classification and localization of faults on the hybrid transmission line consisting of an overhead line and an underground cable. The entropy principle together with fast discrete orthogonal S-transform (FDOST) represented by window dependent bases is utilized for feature extraction and the support vector machine (SVM) classifier model & support vector regression (SVR) model are employed for pattern recognitions to predict the types and locations of faults. After modelling and simulation of the transmission system in Electromagnetic Transient Program (EMTP) software, three phase fault current signals are recorded at one end of the line to extract entropy of FDOST coefficients from each of the three current signals of half cycle duration after fault initiation. The proposed relaying technique is tested on a single-junction and a multi-junction hybrid transmission lines under different fault conditions and is found fast and accurate independent of fault type, fault section, fault resistance, fault inception angle (FIA) and load angle. Another important aspect of the method is that it needs no prior identification of the faulty section for the estimation of fault location. The immunity of the proposed method to noise is also established by testing it with fault current signals impregnated with white Gaussian noise of level 30 dB signal to noise ratio (SNR). [ABSTRACT FROM AUTHOR]

The installed energy production capacity of wind turbines is growing intensely on a global scale, making the reliability of wind turbine subsystems of greater significance. However, many faults like Inter-Turn Short-Circuit (ITSC) may affect the turbine generator and quickly lead to a decline in supplied power quality. In this framework, this paper proposes a Sliding Mode Observer (SMO)-based Fault Tolerant Control (FTC) scheme for Induction Generator (IG)-based variable-speed grid-connected wind turbines. First, the dynamic models of the wind turbine subsystems were developed. The control schemes were elaborated based on the Maximum Power Point Tracking (MPPT) method and Indirect Rotor Flux Oriented Control (IRFOC) method. The grid control was also established by regulating the active and reactive powers. The performance of the wind turbine system and the stability of injected power to the grid were hence analyzed under both healthy and faulty conditions. The robust developed SMO-based Fault Detection and Isolation (FDI) scheme was proved to be fast and efficient for ITSC detection and localization. Afterwards, SMO were involved in scheming the FTC technique. Accordingly, simulation results assert the efficacy of the proposed ITSC FTC method for variable-speed wind turbines with faulty IG in protecting the subsystems from damage and ensuring continuous connection of the wind turbine to the grid during ITSC faults, hence maintaining power quality. [ABSTRACT FROM AUTHOR]

Early and accurate detection of incipient cable faults is of a great interest to the utility industry. Such faults can be classified into subcycle and multicycle types. Although a lot of research has been conducted on subcycle types of faults, little work has been done for multicycle types of faults. This paper proposes a novel method for detecting and locating a multicycle incipient fault in a cable. The incipient fault is modeled as a self-clearing arcing fault. The distortion degree of calculated voltage is used to detect the occurrence of an incipient fault. The degree of match between the measured and calculated waveforms is used to guide the search for the fault distance. The accuracy is further improved by taking into account the incipient fault angle as seen in the voltage waveform and the power loss characteristics. The proposed method has been verified by PSCAD/EMTDC simulations. Lab experiments are also conducted to further validate the proposed detection method. [ABSTRACT FROM PUBLISHER]

The integrity of an electrical cable is vital for the reliability and safety of a system. The change in operating conditions of the electrical cable often leads to unanticipated faults or premature ageing and any such defects has to be monitored so that corrective measures can be taken within the time limit. This is relevant particularly in the case of ships since they cannot afford discontinuity in power supply. In this paper, an experimental setup is developed to create and monitor the intermittent faults in ship electrical system using power line communication. The advantage of this technique is its non-intrusive nature in monitoring the faults. [ABSTRACT FROM AUTHOR]

This paper presents a case study of an intermittent audio failure analysis of a remote speaker-microphone module for a two-way radio. A root cause analysis was undertaken to identify probable causes of the intermittent failure, followed by a series of experiments to determine the strength and the intermittent audio failure load of cable components and the fully assembled cable. The combined experimental and finite element results demonstrated that the main contributor of the intermittent audio failure was the micro surface cracks on the copper conductor strands. In addition, the combination of the component materials and design of the cable have also contributed to the non-uniform state of residual stress induced in the copper conductors which have reduced the ability of the copper conductors to withstand the normal handling load under the influence of micro surface cracks. [ABSTRACT FROM AUTHOR]

Decomposition of the time reversal operator (DORT) was recently applied to the problem of detection and location of soft faults in wire networks and proved effectual when dealing with a single fault, even in the case of complex network configurations. In this paper, the case of location of multiple faults is addressed, first proving that the standard DORT formulation does not allow one to take a clear decision about the individual position of each fault. An alternative version of the DORT based on an updating procedure is presented and demonstrated to enable accurate and selective location of multiple soft faults. The proposed procedure is also shown to allow estimating the reflection coefficient of each fault, thus giving access to their severity. [ABSTRACT FROM AUTHOR]

In the existing experimental studies of cable subjected to fire home and abroad, there is a problem that the failure criterion is not uniform. In this paper, the criteria used in the past has been summarized and classified, a new criterion based on the cable working condition is presented which takes the effect of fire consequences in account. The failure time calculated by using this criterion could not only reflect the maximum working ability of the cable, but also reduce the error caused by the sample randomness. Through the experimental study, we find that the result is more accurate and closer to the practical application. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to improve the management of cables that need much time and work in the measurement environment that has many multichannel cables. Therefore, a monitoring system that inspects faults and connection states of multichannel cables is suggested and designed. The system is based on time-domain reflectometry (TDR) and has two features that distinguish it from the precedent researches. One of them is a hardware interface for the multipair cable, which is a channel distributor designed using a switch. The other is the TDR-signal analysis algorithm based on the database. In other words, the system can check a number of signal wires included in a multichannel cable automatically with one step. In addition, it is able to show results of the signal analysis immediately. The performance of such a system is verified through tests. As a result, it is shown that the monitoring system is fast and reliable and it provides a reasonable analysis result on the TDR signal. [ABSTRACT FROM PUBLISHER]

The method presented in this paper addresses the problem of voltage sag state estimation. The problem consists in estimating the voltage sags frequency at nonmonitored buses from the number of sags measured at monitored sites. Usually, due to limitations on the number of available voltage sag monitors, this is an underdetermined problem. In this approach, the mathematical formulation presented is based on the fault positions concept and is solved by means of the singular value decomposition technique. The proposed estimation method has been validated by using the IEEE 118 test system and the results obtained have been very satisfactory. [ABSTRACT FROM PUBLISHER]

This paper proposes a novel out-of-step protection technique using the state-plane representation of the generator speed and power angle. The critical clearing angle is computed using the principle that the total energy of the system at the instant the fault is cleared should be equal to the maximum potential energy of the system. The critical clearing time corresponding to the value of critical clearing angle is obtained directly using the time calibration of the relative speed versus power-angle solution curve. The simultaneous calculation of the critical clearing angle and the time make the proposed approach much faster than the two-blinder scheme. The proposed state-plane prediction scheme is used to detect the first swing out-of-step condition in a two-area test system using system-wide information. The two generators are represented with a single-machine infinite bus equivalent system, and the state-plane algorithm is applied to the reduced equivalent. Electromagnetic transient simulations are carried out using PSCAD/EMTDC^TM to test the proposed algorithm in the two-area test systems. The simulation studies show that the proposed method is computationally efficient and accurate. The technique also does not require any offline studies. [ABSTRACT FROM PUBLISHER]

This paper presents an orthogonal decomposition method, which is used to extract information from the current transient signals generated after a fault. The orthogonal basis functions are obtained under the condition of maximizing variability (variance) of input signals which, in turn, allows for finding an optimal representation of fault data. The results of the decomposition bring remarkable patterns described by transient signals into sight. Directionality, which appears as one of the foremost features, is highly related to the fault inception angle. This relation is then used to determine the fault direction just by comparing the steady-state prefault voltage angle and the angle of the vector resulting from the representation of the current signal in the space given by the first two orthogonal functions. Time windows shorter than 2 ms are used. Thus, the methodology can be applied in high-speed protection schemes. [ABSTRACT FROM PUBLISHER]

A fault detection and isolation scheme for low-voltage dc-bus microgrid systems is presented in this paper. Unlike traditional ac distribution systems, protection has been challenging for dc systems. The goals of the proposed scheme are to detect the fault in the bus between devices and to isolate the faulted section so that the system keeps operating without disabling the entire system. To achieve these goals, a loop-type dc-bus-based microgrid system, which has a segment controller between connected components, is proposed. The segment controller consists of master and slave controllers that monitor currents and control the segment separation, which include solid-state bidirectional switches and snubber circuits. The proposed system can detect faults on the bus regardless of fault current amplitude or the power supply's feeding capacity. The proposed concepts have been verified by OrCAD/PSpice simulations and experiments on hardware test bed. [ABSTRACT FROM PUBLISHER]

In some situations, utilities may try to “save” the fuse of a circuit following temporary faults by de-energizing the line with the fast operation of an upstream recloser before the fuse is damaged. This fuse-saving practice is accomplished through proper time coordination between a recloser and a fuse. However, the installation of distributed generation (DG) into distribution networks may affect this coordination due to additional fault current contributions from the distributed resources. This phenomenon of recloser-fuse miscoordination is investigated in this paper with the help of a typical network that employs fuse saving. The limitations of a recloser equipped with time and instantaneous overcurrent elements with respect to fuse savings, in the presence of DG, are discussed. An adaptive relaying strategy is proposed to ensure fuse savings in the new scenario even in the worst fault conditions. The simulation results obtained by adaptively changing relay settings in response to changing DG configurations confirm that the settings selected theoretically in accordance with the proposed strategy hold well in operation. [ABSTRACT FROM PUBLISHER]

Arc suppression coil systems are able to improve the high-voltage system reliability and safety. One of the reasons why these systems are not more widely used is the occurrence of simultaneous faults caused by the neutral voltage displacement combined with the transient voltages at the time of the initial earth fault. These transient over-voltages are analysed in detail and the capability of system components to withstand the over-voltages is assessed. Simple methods to estimate the transient voltages on overhead power systems are developed. Testing of the ability of power system components to withstand transient over-voltages and a new method of minimising the transient over-voltages is proposed. [ABSTRACT FROM AUTHOR]

A novel methodology to provide effective fault protection featuring high speed and excellent selectivity is presented. Principal component analysis made up of a set of travelling wave current signals, measured at one end of the transmission line, exhibits a well-defined pattern for faults of the same type. This work discloses that the fault current signal projected on the principal component coordinates can define the position, the insertion angle and the fault type (single-phase to ground, isolated two-phase, two-phase to ground and three-phase faults) on transmission lines. In this manner, it is possible to effectively categorise internal faults as well as distinguish when the fault is outside the line. Time windows less than a quarter of cycle of the power frequency are used to measure the current signals, thus the methodology is applicable for high-speed protection systems. [ABSTRACT FROM AUTHOR]

This paper examines the effects of Thyristor Controlled Voltage Regulator (TCVR) and Thyristor Controlled Phase Angle Regulator (TCPAR) on the transient stability improvement of a multi-machine power system. The proposed control strategy is proposed to supply a supplementary control signal to both FACTS devices to increase the Critical Clearing Time (CCT). To show the effectiveness of the dynamic oscillation , the criterion of relative rotor angles, using Runge-Kutta method is used to demonstrate that the proposed TCVR and TCPAR controllers significantly improves the dynamic performance of the power system. The effectiveness of the proposed method is tested on the WSCC3 nine-bus system applied to the case of three-phase short circuit fault in one transmission line. The simulation results and their comparison are presented in this paper. [ABSTRACT FROM AUTHOR]

This paper presents an effective technique to reconstruct faulty wiring networks and/or to localize the defects affecting the branches of a wiring network from the reflectometry response. The direct problem (propagation in the cables) is modelled by RLCG circuit parameters and the Finite Difference Time Domain (FDTD) method whereas the inverse problem is solved using Genetic Algorithms (GAs). In a first step the forward problems is validated by comparison with experimental and simulated data. In a second step the proposed reconstruction method is applied on different configurations and the results are discussed. [ABSTRACT FROM AUTHOR]

The electric power markets have enforced new power service quality that makes fault location in power distribution systems an obligatory issue. This paper presents a novel high impedance fault detection and location approach based on wavelet transform and artificial neural networks (ANNs). The system simulation of 20kV underground power distribution has been implemented using EMTP/ATP software. The simulated data is analyzed using advanced signal processing technique based on wavelet analysis to extract useful feature from signals and this is then applied to the artificial neural networks for locating high impedance faults in a practical underground distribution system. The paper concludes by comprehensively evaluation the performance of the technique developed in the case of high impedance faults. The results indicate that the fault location technique has an acceptable accuracy under a whole variety of different fault conditions and system parameter changing with cable ageing and altering of load taps position. [ABSTRACT FROM AUTHOR]

From a direct three-phase circuit analysis, an accurate fault-location algorithm has been obtained for the line-to-line fault as an extension of the author's previous work for line-to-ground fault location. Robustness of the proposed algorithm to load impedance uncertainty is enhanced by the introduction of impedance compensation using voltage and current measurements. Simulation results show a high degree of accuracy and robustness to load uncertainty. [ABSTRACT FROM AUTHOR]

This paper presents a concept of fault-location observability and a new fault-location scheme for transmission networks based on synchronized phasor measurement units (PMUs). Using the proposed scheme, minimal PMUs are installed in existing power transmission networks so that the fault, if it occurs, can be located correctly in the network. The scheme combines the fault-location algorithm and the fault-side selector. Extensive simulation results verify the proposed scheme. [ABSTRACT FROM AUTHOR]

In this paper, investigation of a novel fault detection concept for line protection is presented. In this concept, the difference and average quantities for phase active and reactive power entering and leaving the line are compared. Performance of the developed detector is computed under sampling misalignment as compared with conventional current differential approach. This computation is carried out via simulating a tie line connecting two power system networks using the Electromagnetic Transient Program (EMTP). The detector sensitivity for internal fault and stability for external fault are examined for wide range of fault resistance and operating conditions. The test results show distinguished performance of the proposed power differential concept in detecting high impedance faults and remarkable stability during system severe power swings. [ABSTRACT FROM PUBLISHER]

In complex emergency situations, failed protection relays and circuit breakers (CBs) have to be identified in order to begin the restoration process of a power system. This paper proposes a novel neural-network approach to identify multiple failures of protection relays and/or CBs. The approach uses information received from protection systems in the form of alarms and is able to deal with incomplete and distorted data. All possible emergencies are simulated and analyzed separately for each section of a power system. Taking into consideration supervisory control and data-acquisition system malfunctions, the corrupted patterns are used to train neural networks. The preliminary classification of emergencies into two different classes is applied to improve the system's performance. The evaluation of results shows that the overall error rate does not exceed 5%. The developed system was tested on a real power system. [ABSTRACT FROM PUBLISHER]

Presents a method for the analysis of high-impedance fault generated signals utilizing the Morlet wavelet transform approach. Wavelet basis function; Detection procedure; Feasibility as a potential alternative in the area of power system relaying applications.

Studies digital fault location for high resistance grounded electric power transmission lines. Importance of fault locators to support prompt recovery from transmission line fault; Effect of multiple load taps on single-phase-to-ground fault location; Fault location methods for parallel two-circuit two-terminal transmission lines.

The detection of insulators in power transmission and transformation inspection images is the basis for insulator state detection and fault diagnosis in thereafter. Aiming at the detection of insulators with different aspect ratios and scales and ones with mutual occlusion, a method of insulator inspection image based on the improved faster region-convolutional neural network (R-CNN) is put forward in this paper. By constructing a power transmission and transformation insulation equipment detection dataset and fine-tuning the faster R-CNN model, the anchor generation method and non-maximum suppression (NMS) in the region proposal network (RPN) of the faster R-CNN model were improved, thus realizing a better detection of insulators. The experimental results show that the average precision (AP) value of the faster R-CNN model was increased to 0.818 with the improved anchor generation method under the VGG-16 Net. In addition, the detection effect of different aspect ratios and different scales of insulators in the inspection images was improved significantly, and the occlusion of insulators could be effectively distinguished and detected using the improved NMS. [ABSTRACT FROM AUTHOR]

This work analyses a two-terminal algorithm designed to locate unsymmetrical faults on 110 kV power transmission lines. The algorithm processes synchronized voltage and current data obtained from both ends of the protected transmission line and calculates the distance of the fault. It is based on decomposing the equivalent circuit into the positive-, negative- and zero-sequence components and finding the point where the output voltages of the right and the left side of the transmission line are equal. Compared to the conventional distance relay locator, the accuracy of this method is higher and less influenced by the fault resistance, the parallel-operated line effect and line asymmetry, as discussed in this work. It is, however, very sensitive to the synchronization accuracy. The mathematical model of the power system was created in the PSCAD (Power Systems Computer Aided Design) environment and the computational algorithm was implemented in Mathematica software. [ABSTRACT FROM AUTHOR]

Summary: Closed‐loop operation of distribution network has attracted more attention recently to improve supply reliability and adopt distributed energy resources friendly. But its protection is usually independent of distribution automation system (DAS). This article presents a pilot protection method for closed‐loop distribution network with underground cable by comparing current phase, which can be accomplished by remote terminal units (RTUs) in DAS. Firstly, operation value of RTUs is designed on the current variation after fault and the RTUs are synchronized automatically based on fault signal. Secondly, the current phase characteristic of positive‐sequence fault component is analyzed when various short circuit fault occurs at different locations. Based on the current phase difference, the state of ring network cabinet is classified into four types, and uniform fault location rule by adjacent RTUs is designed. The fault can be located and isolated directly by cooperation of adjacent RTUs. The setting principle and the operation logic for the pilot protection are given, and its performance is analyzed. Finally, simulation model based on PSCAD is constructed. The simulation results prove that this protection can locate and isolate faults timely on the premise of high sensitivity. It has strong ability of enduring fault resistance, and it can fit closed and open operation mode. [ABSTRACT FROM AUTHOR]