Traveling Wave Fault Location Research Articles

A high frequency reflected current signals-based fault type identification method

The main objective of this paper is to identify fault type and faulted phase focus on the time delay values of reflected phase and modal current signals. The proposed method identifies fault type with the help of amplitude maxima of detail wavelet coefficient of residual current. The time delay values of phase and modal current reflected signals are used to detect faulty phase instead of using threshold values. Using time delay as a fault type identification parameter is achieved to save the overall protection system operating time because time delay is also the main feature of traveling wave fault location method. Moreover, to ensure the applied wavelet filter, the proposed algorithm is tested with the detail information of the three mother wavelets, such as db4, db6 and db8 and chosen the highest classification accuracy. Various disturbance events were tested with changing different possible fault types, faulted-feeders, fault resistances, fault locations and fault inception times on a loop distribution system. The robustness of the proposed faulted phase selection algorithm is performed through MATLAB Simulation.

Single-ended data based fault location method for multi-branch distribution network

A novel single-ended travelling wave fault location method applicable to the distribution network with multi-branches is presented in this paper. The method only depends on the arrival times of the initial aerial-mode and zero-mode travelling wave, and it can solve the truncation error problem caused by discrete sampling mechanism. In addition, the method is not affected by structure of a distribution system. The feasibility and effectiveness of the presented method is verified by PSCAD/EMTDC simulation results.

A Novel Traveling Wave Fault Location Method for Transmission Network Based on Directed Tree Model and Linear Fitting

In order to solve the problem of inaccurate fault location in the transmission network under some abnormal conditions, such as traveling wave location device faults, startup failure and time recording error, a novel traveling wave fault location method based on directed tree model and linear fitting is proposed. A directed tree model of the fault traveling wave transmission along the shortest path is established based on graph theory analysis of traveling wave transmission network. Two straight lines are fitted on the coordinate plane where the accurate fault location is obtained direct by coordinate information of the intersection of these two fitted straight lines (FSLs), according to the transmission characteristics of the fault traveling wave in the directed tree model. The wave velocity is used as the slope of the fitted straight line, and the influence of its uncertainty on the fault location is eliminated. The time record error points of the location device are automatically eliminated in the linear fitting. PSCAD simulation results prove that fault information of the entire transmission network is comprehensively utilized by the proposed method and the ring network is automatically unlooped. The reliability and accuracy of fault location are remarkably improved, particularly for the fault scenarios with recorded information abnormity.

Travelling wave fault location principle for hybrid multi-terminal LCC-VSC-HVDC transmission line based on R-ECT

This paper investigates the fault location issue of hybrid multi-terminal high voltage direct current (HVDC) overhead transmission line based on the line commutated converter (LCC) and voltage source converter (VSC). There exists two issues that should be addressed: (i) the travelling wave (TW) fault location principle’s adaptability to multi-terminal network topology and converter structures; (ii) the transfer method of high frequency TW signal. Therefore, a novel TW fault location principle for the hybrid multi-terminal LCC-MMC-HVDC transmission line is proposed based on the Rogowski coli based electronic current transformer (R-ECT). Firstly, the high frequency TW transfer capability of the R-ECT is studied. Secondly, a novel TW fault location principle based on the secondary differential current travelling wave (D-CTW) is proposed. Eventually, in order to verify the high accuracy of the proposed principle, a typical ±400 kV hybrid three-terminal LCC-VSC-HVDC transmission system is used for the case study based on PSCAD/EMTDC. Furthermore, its robustness against different fault locations, different fault resistances and different fault types is also investigated.

Single-Ended Traveling Wave Fault Location Method in DC Transmission Line Based on Wave Front Information

The result of single-ended traveling wave fault location method based on wavelet transform will be affected by false wavelet transform modulus maxima (WTMM) points. In this paper, fault distance/impedance information contained in the wave front of the traveling wave is analyzed first. Then, the fitting method based on generalized logistic function is proposed to extract the fault information. Based on the fitting results, a predictor–corrector fault location method is proposed, which includes the following content. First, the fitting coefficients of the zero-mode fault current wave front are used to estimate fault distance and fault impedance interval. Second, the arrival time of the line-mode fault current reflected wave can be calibrated and the distance calculation formula can be selected according to the fault distance estimation interval. Last, the fault distance will be corrected to be within the fault distance estimation interval, if the first reflected wave is undetected. A model of ±400 kV DC transmission project is built in PSCAD/EMTDC. The simulation results show that the fitting coefficients can directly correspond to fault distance/impedance. The proposed method can effectively eliminate the influence of the false WTMM points, and give the accurate fault location results as well as fault impedance interval.

TravellingWave Fault Location System based on IEC61850

Travelling wave fault location (TWFL) system has been matured in recent years due primarily to the availability of high speed sampling techniques, fast communications technology and GPS time synchronization. However, it has not yet been fully integrated into the digital substation based on IEC61850 standard. Proposal for modeling the TWFL system by the IEC61850 standard has already been proposed in another paper. This paper focuses on the communication requirements of the TWFL system in a digital substation, both at the station level and the process level. The application of GOOSE messages and the need for high speed sampling merging unit are discussed. The paper also reports on the latest research into the electronic transformer technology which can satisfy the high speed sampling requirements of TWFL.

A Two-End Traveling Wave Fault Location System for MV Cables

In this paper, a new low-cost device is proposed for fault location in power distribution system. The device is part of a system that should include several units installed in couples at the two ends of medium voltage (MV) cable lines. Their low cost justifies a widespread installation of these devices, moreover other functionalities could be considered so as to enrich the potential of the system for MV cables monitoring and asset management. The system exploits a two-end traveling wave technique, low complexity, and low-cost solutions both for the analog front end as well as for the communication infrastructure. A LoRa network is indeed considered as wireless modulation technique perfectly suited when communication links with three characteristics are needed: low power, low bit rate, and long range. This paper shows the device that has been set up in Prysmian Electronics with some experimental phases showing the effectiveness of the proposed solution and the further developments expected.

Fault location of transmission lines connecting with short branches based on polarity and arrival time of asynchronously recorded traveling waves

Due to complex reflection and refraction at line terminals, traditional single-end traveling wave (TW) fault location (FL) cannot be directly applied to transmission lines connecting with short branches. This paper presents an improved single-end TW FL method for this special case. Three TW recorders are required to be mounted at local, middle and remote terminals of the transmission line but accurate synchronous sampling is not required. In the proposed method, combined with the defined polarity coefficients of current TW wave fronts (WFs), the absolute difference of the time differences of arrival (TDOAs) of the modulus TWs at both terminals is firstly utilized to determine whether the fault occurs in the transmission line. If the fault is detected in the transmission line, the fault line section can be then determined by the ratio of the TDOAs of the modulus TWs recorded at both terminals. Finally, the TDOAs of the first two WFs at the three TW recorders are calculated and compared with the theoretical ones to determine the source of the second WF. The corresponding single-end accurate FL formula is selected to pinpoint the fault. A simulation model of a transmission line connecting with short branches is constructed by PSCAD/EMTDC. Various faults are simulated to verify the proposed FL method. The calculation results demonstrate that the method is not affected by FLs, impedances, inception angles, noises and longer lines to a certain extent.

Traveling-wave fault location algorithms in hybrid multi-terminal networks with a tree-like structure

Traveling-wave methods of the fault location prove their practical efficiency for the power transmission lines (TL) with an arbitrary configuration of any voltage class. This paper formulates algorithms to automate the process of the fault location in the TLs with a tree-like structure. The error of the simplified traveling-wave fault location (TWFL) algorithm based on the average propagation velocity of the transient signals (TS) is analyzed. A tabular algorithm for TWFL, which considers different propagation velocities of the TS in different segments of a hybrid network is proposed. An adaptive TWFL algorithm that considers the registration of the TSs with known places of their occurrence is proposed, to reduce the impact of the inaccuracy of the initial different network segments’ lengths and TS’s propagation velocity determination.

Исследование изменения временных параметров сигналов переходного процесса при распространении в распределительной сети 6(10) кВ для задачи определения места повреждения волновым методом

Исследование изменения временных параметров сигналов переходного процесса при распространении в распределительной сети 6(10) кВ для задачи определения места повреждения волновым методом

A Method of Traveling Wave Fault Location for Distribution Network Based on Incidence Matrix

Distribution network fault location technology is currently mainly concentrated in sub section positioning and based on the offline signal injection method precise positioning stage, this paper proposes a new online traveling wave fault location method based on the correlation matrix, the method based on line distributed terminal high sampling data waves, with terminal data construction association matrix, through the correlation matrix of the symmetry and correlation determine fault section and identify abnormal data set, on the basis of further accurate fault location, so as to improve the reliability and accuracy of fault location in distribution network.

Influence on Traveling Wave Fault Location from Structural Characteristics of Railway Automatic Blocking Electric Lines

This paper, taken the railway 10kV automatic blocking electric line as the research object, discusses some structure factors which may affect the ranging accuracy of traveling wave method in the practical application of traveling wave fault location device, and establishes the simulation model to verify. These structure factors include the effect of transition resistance, terminal load combination form and the line branches' number before fault point.

Global Positioning System and GLObal NAvigation Satellite System constellations for better time synchronising reliability

The demand for accurate time synchronisation available 24/7 increases with the growth of critical substation applications, such as phasor measurement, merging units, travelling-wave fault location and current differential protection schemes. In order to yield the best accuracy and granularity from such applications, the use of a common, reliable and precision-time reference is essential.

Type D travelling wave fault location on branched underground low‐voltage networks

Low voltage cable faults are frequently associated with arcing at the fault which creates 2 high frequency transients which propagate away from the fault towards opposite ends of the cable and whose difference in arrival times can be used to determine the fault's location using the Type D method. A variant of the Type D method, known as the Transient Recording System (TRS) using asynchronous data acquisition units (ADAU) has been used successfully in situations where multiple branches on a cable have precluded the use of other travelling wave methods. The range, and precision of location, of the TRS method is extended by the use of a Marker Unit (MU) which allows the distance and direction to a fault to be determined relative to the point of connection of the MU. The asynchronous data acquisition units operate in ‘listening’ mode and are triggered by the arrival of the transients created by the fault arc. Prior to triggering, the ADAUs continuously (over)write all received data into their cyclic buffers, including the low amplitude MU pulses. Shortly after triggering the (over)writing of the cyclic buffer stops and earlier (pre-trigger) data retained – including the received MU pulses.

Speeded‐up robust features based single‐ended travelling wave fault location: a practical case study in Yunnan power grid of China

Reflected wave identification is the core of single-ended travelling wave fault location, in which the obvious superimposed oscillation is the main obstacle for precise reflected wave identification with field data. This study proposes a reflected wave identification method based on speeded-up robust features, which can gradually approximate from the possibly largest fault distance to the near-end fault distance so as to exclude the reflected wave from time window containing initial wave. In particular, the time window segmentation divides initial wave and reflected wave into two inconsistent time windows, hence the reflected wave from the superimposed oscillation that usually follows the travelling wave can be effectively separated, such that the identification of reflected wave can be significantly simplified. Lastly, the superimposed oscillation is thoroughly analysed while both the field data with and without obvious superimposed oscillation are presented to evaluate the effectiveness of the proposed approach. Field data obtained from 21 substations scattered among Yunnan power grid of China validate the implementation feasibility of the proposed method.

A Study of Travelling Wave Fault Location

In the present modern era with the development of power systems, fast and accurate faults locations becoming more and more important. Power grids produce transient travelling wave signals, which transmit along the transmission line to each substation with the speed approaching the velocity of light. Using the exact arrival time of the fault traveling wave and the waveform characteristics recorded at each substation, the traveling wave based fault location and protection can be realized. The fault location has high precision, and the protection has fast action speed. So, current transformer saturation low frequency oscillation and fault resistance cannot influence it. Fault location device (FLD) is installed at each substation in power grid, and travelling wave host computer is installed in control center. When a fault occurs, FLD records the switch operation information and the arrival time of the travelling wave, the information is then transmitted to the host computer. Lightning strike fault location method can only locate the fault caused by lightning, and it hardly satisfies the operation requirements in power system. Travelling wave fault location method with GPS is simple and with high precision, it has been applied in extra-high-voltage.

An Adaptive Fault-Location Method for a Power-Transmission Line Using Pulse Registration on a High-Frequency Wave Path

An adaptive traveling-wave method to improve the accuracy of fault location has been developed. The suggested method can compensate for an error of the two-sided method caused by the dispersive nature of a phase wire along which a high-frequency electromagnetic pulse propagates from the point of the fault. The error in fault location has been determined depending on the means of registration of a high-frequency signal. Some recommendations on connection of facilities to register electromagnetic pulses used in the devices of traveling-wave fault location have been provided. The suggested method allows one to substantially reduce errors of estimation of distance to the point of a fault and is less affected by external factors. The developed method can be applied in both in existing and future devices for fault location.

An enhanced fault detection and location estimation method for TCSC compensated line connecting wind farm

The paper presents a new approach to enhance the fault detection, and location determination based on travelling waves using Fast Discrete S-transform (FDST) for TCSC compensated lines connecting to wind farm. The FDST is applied to the modal components of measured currents at each terminal to detect the arrival time of the first travelling wave (transient) produced by the fault. The proposed method includes detecting the terminal with fastest arrival time of wave to identify the faulted section and estimate the fault location by using proper distance index. The simulation results have demonstrated good performance of the proposed scheme under different fault locations, fault resistances, fault inception angles, fault types, faulted sections, variations in TCSC parameters and changing wind speeds. The performance validation on the real-time digital simulator (RTDS) platform enhances the applicability of the proposed protection scheme for the TCSC based compensated line integrated with wind farm. The performance comparison with the conventional travelling wave fault location algorithms using Continuous Wavelet Transform (CWT) shows potential ability of the proposed method.

Research on multi-terminal traveling wave fault location method in complicated networks based on cloud computing platform

Cloud computing technology is used in traveling wave fault location, which establishes a new technology platform for multi-terminal traveling wave fault location in complicated power systems. In this paper, multi-terminal traveling wave fault location network is developed, and massive data storage, management, and algorithm realization are implemented in the cloud computing platform. Based on network topology structure, the section connecting points for any lines and corresponding detection placement in the loop are determined first. The loop is divided into different sections, in which the shortest transmission path for any of the fault points is directly and uniquely obtained. In order to minimize the number of traveling wave acquisition unit (TWU), multi-objective optimal configuration model for TWU is then set up based on network full observability. Finally, according to the TWU distribution, fault section can be located by using temporal correlation, and the final fault location point can be precisely calculated by fusing all the times recorded in TWU. PSCAD/EMTDC simulation results show that the proposed method can quickly, accurately, and reliably locate the fault point under limited TWU with optimal placement.

A Comparison Study of Learning Algorithms for Estimating Fault Location

Fault location is one of the important scheme in power system protection to locate the exact location of disturbance. Nowadays, artificial neural networks (ANNs) are being used significantly to identify exact fault location on transmission lines. Selection of suitable training algorithm is important in analysis of ANN performance. This paper presents a comparative study of various ANN training algorithm to perform fault location scheme in transmission lines. The features selected into ANN is the time of first peak changes in discrete wavelet transform (DWT) signal by using faulted current signal acted as traveling wave fault location technique. Six types commonly used backpropagation training algorithm were selected including the Levenberg-Marquardt, Bayesian Regulation, Conjugate gradient backpropagation with Powell-Beale restarts, BFGS quasi-Newton, Conjugate gradient backpropagation with Polak-Ribiere updates and Conjugate gradient backpropagation with Fletcher-Reeves updates. The proposed fault location method is tested with varying fault location, fault types, fault resistance and inception angle. The performance of each training algorithm is evaluated by goodness-of-fit (R<sup>2</sup>), mean square error (MSE) and Percentage prediction error (PPE). Simulation results show that the best of training algorithm for estimating fault location is Bayesian Regulation (R<sup>2 </sup>= 1.0, MSE = 0.034557 and PPE = 0.014%).