Download or read book Investigation of Fault Location Performance Utilizing Synchronized Phasor Measurements with a Two ended Fault Location Impedance Method written by Enrique Quintero and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Transmission lines are an essential part of the electrical grids. Thus, utilities cannot afford to have any transmission line out service because it can result in power outages and causes overloading other lines in the same grid. However, transmission lines are exposed to faults caused by short circuits, birds, adverse weather conditions, and human made accidents. Transmission line faults can be temporary or permanent. Temporary faults are mostly self-cleared. But, permanent faults do not self-cleared and cause damage to transmission line infrastructure. Most of these faults result in mechanical damage to power lines, poles, or insulators which need to be repaired before returning the line to service. For this reason, transmission line faults must be located accurately to allow field crews arrive at the scene and repair the faulted equipment as soon as possible. The most obvious method to locate the faulted equipment is just to patrol the whole line, but one of the main obstacles following that method are the geographical layout in some sections of the line making difficult for the field crews accessing to the scene, the long time it takes to patrol the line and the associated high cost which makes it uneconomical. Meanwhile, if the utility has a software tool to calculate fast and accurate fault location under any power system conditions, the utility will enhance the restoration time of the line with less cost and consequently it will short customer outage time by pointing field crews to narrow range to check. Fault location algorithms are one method for utilities use to detect fast and accurate fault location. However these fault location algorithms are typically embedded in fault locator devices or protective relays. This is an obstacle because in order to get the fault location out those devices, they need to be interrogated and normally these devices are located in remote areas. Now with the advances in synchrophasor technology, it is possible to collect synchronized phasor measurements in a convenient central location such as operating center or dispatch center and perform fast and accurate fault location based on synchronized phasor measurements. For this thesis, an impedance based fault location technique will be used because it is the most simple and practical method for implementation. However, this fault location technique in conjunction with relay data is known for being susceptible to a number of sources of errors. So by utilizing real-time and very accurate synchronized phasor measurement data, this thesis will investigate how accurate the impedance based fault location technique result.

Download or read book Wide Area Power Systems Stability Protection and Security written by Hassan Haes Alhelou and published by Springer Nature. This book was released on 2020-09-21 with total page 614 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book proposes new control and protection schemes to improve the overall stability and security of future wide-area power systems. It focuses on the high penetration levels of renewable energy sources and distributed generation, particularly with the trend towards smart grids. The control methods discussed can improve the overall stability in normal and abnormal operation conditions, while the protection methods presented can be used to ensure the secure operation of systems under most severe contingencies. Presenting stability, security, and protection methods for power systems in one concise volume, this book takes the reader on a journey from concepts and fundamentals to the latest and future trends in each topic covered, making it an informative and intriguing read for researchers, graduate students, and practitioners alike.

Download or read book Power System Fault Diagnosis written by Md Shafiullah and published by Elsevier. This book was released on 2022-01-14 with total page 430 pages. Available in PDF, EPUB and Kindle. Book excerpt: Power System Fault Diagnosis: A Wide Area Measurement Based Intelligent Approach is a comprehensive overview of the growing interests in efficient diagnosis of power system faults to reduce outage duration and revenue losses by expediting the restoration process.This book illustrates intelligent fault diagnosis schemes for power system networks, at both transmission and distribution levels, using data acquired from phasor measurement units. It presents the power grid modeling, fault modeling, feature extraction processes, and various fault diagnosis techniques, including artificial intelligence techniques, in steps. The book also incorporates uncertainty associated with line parameters, fault information (resistance and inception angle), load demand, renewable energy generation, and measurement noises. - Provides step-by-step modeling of power system networks (distribution and transmission) and faults in MATLAB/SIMULINK and real-time digital simulator (RTDS) platforms - Presents feature extraction processes using advanced signal processing techniques (discrete wavelet and Stockwell transforms) and an easy-to-understand optimal feature selection method - Illustrates comprehensive results in the graphical and tabular formats that can be easily reproduced by beginners - Highlights various utility practices for fault location in transmission networks, distribution systems, and underground cables.

Download or read book Fault Location on Power Networks written by Murari Mohan Saha and published by Springer Science & Business Media. This book was released on 2009-11-25 with total page 425 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fault Location on Power Lines enables readers to pinpoint the location of a fault on power lines following a disturbance. The nine chapters are organised according to the design of different locators. The authors do not simply refer the reader to manufacturers’ documentation, but instead have compiled detailed information to allow for in-depth comparison. Fault Location on Power Lines describes basic algorithms used in fault locators, focusing on fault location on overhead transmission lines, but also covering fault location in distribution networks. An application of artificial intelligence in this field is also presented, to help the reader to understand all aspects of fault location on overhead lines, including both the design and application standpoints. Professional engineers, researchers, and postgraduate and undergraduate students will find Fault Location on Power Lines a valuable resource, which enables them to reproduce complete algorithms of digital fault locators in their basic forms.

Download or read book Fault Location Using Wide area Measurements and Sparse Estimation written by Guangyu Feng and published by . This book was released on 2015 with total page 111 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis describes a fault location method which relies on scattered wide-area synchronized phasor measurements and usage of sparse estimation techniques. The main contribution is the way fault location is reformulated as a sparse estimation problem. Faulted system is modeled by equivalent terminal bus injections which would cause the same changes in bus voltages with the fault current drawn at any point along the faulted line. Once these injections are estimated, the fact that the ratio between equivalent injections at the two terminal buses depends only on the ratio of serial impedances on each side of the fault point can be used to locate the fault. It is shown that this formulation applies to both two terminal lines as well as teed lines regardless of fault type or resistance. Assuming availability of an accurate three-phase network model and a sufficient number of phasor measurements over the entire network, an underdetermined set of linear equations can be formed and then solved for the sparse equivalent bus injections. Then the problem fits naturally into a Lasso formulation and can be solved via the LARS algorithm. Based on the condition for unique solution for Lasso problem, a scheme for optimal phasor measurement placement is also derived. Furthermore, alternations have been made to the basic implementation of LARS so that the method's reliability, robustness and efficiency is improved.

Download or read book Dynamic System Reduction and Fault Location Identification Using Synchrophasors written by Eithar Nashawati and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The advent of the synchronized phasor measurement units' technology allow for new applications to the power systems and improvement of existing applications. This dissertation presents a new method for synchrophasor-assisted fault location. An initial screening of voltage phase angle swing determines the suspect part of the system where the disturbance occurred. The system is then reduced to a limited number of buses. A Positive-sequence voltage-only method is then used to provide a better estimation of the exact location of the fault using particle swarm optimization. This method is applied to a large power system in North Texas. Real-time synchrophasor measurement units are used from across the power system to identify the fault location. Results are compared to traditional fault location methods that utilize non-synchronized current measurements to locate faults. Several cases are examined and results show accurate estimation of the fault location by using the proposed approach.

Download or read book Study of Fault Location Algorithms for Two terminal Three terminal Multisection Compound Transmission Lines Based on Synchronized Phasor Measurements written by 林子喬 and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book 3rd IEE International Conference on Reliability of Transmission and Distribution Networks RTDN 2005 written by and published by Institution of Electrical Engineers. This book was released on 2005 with total page 364 pages. Available in PDF, EPUB and Kindle. Book excerpt: Modern life relies on the availability of electricity and pressures on network operators to keep the power flowing have never been greater. Power networks of the future need to be even more reliable, work harder and respond in real time whilst coping with increasing embedded generation; yet more than half of the networks of 20 years time are already built. The challenge to managers and engineers is to achieve ever greater reliability with networks built from a mixture of assets at the lowest cost to customers. RTDN 2005 covers aspects of Reliability of Transmission covers topics such as diagnostic techniques, designing for reliability, condition monitoring, control & protection and risk analysis.

Download or read book Fault Location and Parameter Estimation on Overhead Transmission Lines Using Synchronized Sampling written by Ashok Gopalakrishnan and published by . This book was released on 2000 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Transmission Line Fault Location Using Unsynchronized Measurements written by Shoaib Hussain and published by . This book was released on 2013 with total page 119 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Designing reliable and accurate fault locating algorithms is still considered a challenge despite the intense research and development efforts transcribed in literature. Modern power system networks have grown in complexity and the increased deregulation of utility markets have helped dedicated fault locator systems garner much attention. Traditional electro-mechanical distance relays can be considered the first in a series of attempts to realize the aim of fault distance location. However, these were designed to provide rapid and reliable indication of the general faulted area rather than furnish fault distance estimates with pin-point accuracy. On the other hand, fault locator systems are expressly designed to provide accurate, reliable and reproducible fault distance solutions that might work with single-ended or two-ended data measurements. The two-ended data measurement provides far more accurate results. However data synchronization between protective relays at both ends is another issue that demands careful consideration. More often than not, modern fault locating algorithms incorporate integrated communication capabilities with sophisticated computational routines to furnish fault location estimates within an acceptable range of accuracy. In this thesis, the solution to transmission line protection problem is modeled as a fault locating algorithm that utilizes unsynchronized measurements"--Abstract.

Download or read book Traveling Wave Based Fault Location written by Samina Yasmin (ME) and published by . This book was released on 2017 with total page 94 pages. Available in PDF, EPUB and Kindle. Book excerpt: Transmission grid system plays a key role in the interconnection of large-scale generation of a country’s power system network supplying loads all across. In many faults statistics, it has been unambiguously indicated that around 75% power system faults occur in transmission lines. This fact has increased the need for correct fault identification and location on transmission lines. Many researchers have developed algorithms based on using current, voltage measurements, and line parameters at a single end or multi-end to locate the fault. However, each of these fault location technique has some operational limitation. This thesis presents single-ended traveling wave fault location method based on wavelet transform and practical implementation on a recently released commercial relay utilizing this principle. A sample system was created in MATLAB SimPower System and simulations carried out for assessing the traveling wave from one end for different fault distance on the transmission lines. Traveling wave propagate close to the velocity of light and it is difficult to capture them so sampling rate was kept high enough to record the traveling wave at fault point. In order to decouple three phases, modal transformation is used to carry the independent analysis of each phase. Signal processing application wavelet transform has been used for feature extraction. MATLAB wavelet toolbox is used to decompose the signal by using discrete wavelet transform with appropriate mother wavelet Daubechies at level one which yields detail coefficient and approximation coefficients. Thereafter, Wavelet transform modulus maxima of detail coefficient is used to extract the sample number of the peaks in the signal. Firstly, two consecutive peaks with their respective sample numbers are used along with the velocity of propagation. Sensitivity analysis is carried out to analyse the system performance under different conditions. Extensive simulations are performed by varying the fault inception angle, fault resistance and mother wavelets showing that the traveling wave fault location method is insensitive to these parameters. All the simulations were performed by keeping the sample rate higher since by keeping sampling rate lower it is not possible to capture the realistic traveling wave which thereby impacts on the performance of any practical relay being tested. In addition to this detailed research assessment carried out, a two bus system network has been modelled using ATP/EMTP and the generated fault signal applied to a new commercial relay (M/s Schweitzer Engineering Laboratories, SEL) using a commercial testing system. By use of synchrowave event software, the fault signal is analysed and the fault distance manually calculated. The average error was around 2% for fault location but relay trip indicated correct fault classification. Analysing the various fault cases it is clearly observed that it is difficult to distinguish between the waves reflected from fault point and from the remote end of the line. This is one limitation of traveling wave fault location method. Low sampling rate and velocity of propagation appear to affect the observed results. The velocity of propagation should be calculated by using the line parameters of the transmission line and sampling rate should be kept higher to get estimated results from modelling. In future, this particular relay should be tested in the field by using the double-ended traveling wave fault location method.

Download or read book Sensitivity Analysis of Impedance based Fault Location Methods written by Neeraj Anil Karnik and published by . This book was released on 2011 with total page 278 pages. Available in PDF, EPUB and Kindle. Book excerpt: Impedance-based methods are used to locate faults on distribution systems because of their simplicity and ease of implementation. These methods require fault voltage and current data along with the positive- and zero-sequence line impedance values (in ohm per unit length) to estimate the reactance or distance to fault location. Inaccuracies in line impedance values, which arise from circuit model errors, have an adverse impact on fault location estimates of the impedance-based methods. Measurement errors in current and voltage transformers can also lead to inaccuracy in estimation. Further, all methods use simplistic models to represent the system load. The load in a practical distribution system does not conform to the oversimplified models leading to errors in estimation of fault location. This thesis presents sensitivity analysis of four impedance-based methods. It focuses on the Takagi, positive-sequence reactance, loop reactance and balanced-load methods. Amongst these four methods, the first three are commonly used for fault location. The fourth method was developed as a part of this work. The objective of sensitivity analysis is to study and quantify the effect of circuit model, measurement and load model errors, on the fault location estimates of the four methods. The results of this analysis are used to establish upper and lower bounds on the estimation errors for each method. The analysis begins with creation of a baseline case using a modified version of the IEEE 34 Node Test Feeder. All the methods estimate the reactance to fault location as a part of this analysis. The baseline case uses accurate line impedances and measurement values in the four methods. The fault location estimates for this case serve as a means of comparison for all subsequent analyzes. Secondly, various circuit model errors are introduced while computing the line impedance values. These errors include inaccurate modeling of four parameters viz. phase conductor distances, conductor sizes, phase to neutral conductor distances and earth resistivity. The erroneous line impedance values, which arise from these circuit model errors, are used in the four methods. The resultant location estimates are compared with those for the baseline case. It is observed that modeling errors in earth resistivity can cause estimation errors of 2% to 5% in the Takagi and positive-sequence reactance methods. These errors can be positive or negative depending upon whether the modeled earth resistivity value is more than or less than the accurate value. The effect of inaccurate modeling of the other three parameters is marginal. Additionally, the Takagi and positive-sequence reactance methods assume line impedances to be uniform while estimating fault location. Although this assumption is a type of circuit model error, it does not lead to significant errors in estimation. The loop reactance and balanced-load methods are insensitive to circuit model errors as they do not use line impedance values while estimating reactance to fault location. The next part is analysis of effect of measurement errors on fault location estimates. Ratio and phase angle errors are deliberately introduced in the current and voltage transformers and the erroneous measurements are used to conduct fault location. This causes 5% to 6% errors in estimation for the Takagi and positive-sequence reactance methods. These estimation errors can be positive or negative depending upon the magnitude of the CT and VT ratio errors and the sign of the phase angle errors. For the loop reactance method, erroneous measurements introduce 8% to 30% errors in fault location. This indicates that the loop reactance method is highly sensitive to measurement errors. The balanced-load method is moderately sensitive and experiences 6% to 7% errors in fault location estimates. Lastly, the effect of load current on fault location estimates is analyzed. When the Takagi and positive-sequence reactance methods are used on a heavily loaded system, they estimate fault location with an error of 5% to 8%. The loop reactance method is severely affected by the level of load current in the system. This method can estimate fault location with nearly 100% accuracy, on a lightly loaded system. However, the estimation errors for this method increase significantly and are in the range of 15% to 30%, as load current in the system increases. In case of the balanced-load method, unbalanced, heavy loads can cause estimation errors of 7% to 25%. The combined effect of all the error sources is taken into account by creating a confidence interval for each method. For the Takagi and positive-sequence reactance methods, the actual fault location can be expected to lie within ±10% of the estimated value. The fault location estimation error for the loop reactance and balanced-load methods is always positive. The actual reactance-to-fault is within -30% of the value estimated by these methods.

Download or read book Improving Fault Location Through Interpole Analysis of Circuit Breaker and Automatic Reclose Scheme Operation written by Liang Ji and published by . This book was released on 2012 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This research concentrates on the development and evaluation of novel single ended impedance based fault location methods, which are easy and economical to implement in practice. The conventional single ended impedance based fault location methods normally suffer from negative effects associated with variability and inaccuracies in fault resistance, distance to fault and from the impact of variable remote end short circuit level. A novel concept of a single ended impedance based fault location method using analysis of 'interpole' states, which arise during the operation of the circuit breaker as the individual poles open sequentially, has been developed. The proposed fault location technique has been shown to have a very high theoretical accuracy by eliminating the aforementioned negative effects associated with conventional single ended impedance based methods. The thesis describes how the developed technique operates through comparing simulated voltage and currents during the interpole states with the actual measured voltage and currents, and searches for a match that may be indicative of fault location. When a match is found within a pre-specified tolerance error from analysis of the initial "during fault" state, the ranges of corresponding possible fault locations, fault resistances and remote end short circuit levels used in the simulation are noted. The ranges of all possible values are subsequently reduced through analysis of the consecutive interpole stages as each pole of the circuit breaker opens sequentially to finally interrupt the flow of current in all three phases. The final, most accurate, fault location is obtained following on from analysis of the final state. Another single ended impedance based fault location method has been developed that extends the analysis to the operation of single/three phase auto-reclose schemes. Similarly with previous method, the second method also uses the analysis of different system states, which are arisen during the auto-reclose operation, and improves on the accuracy of the method that only analyses the single operation of the circuit breaker. The methods are demonstrated using EMTP/ATP simulation models for a variety of different cases and it is shown how high accuracy has been achieved, with improved performance when compared with conventional single ended impedance based method (Takagi method and network impedance method). Additionally, it is a potentially economic solution, as only local end data is required. The thesis concludes with an overview of ongoing and future work that has the intention of moving the work forward towards implementation within commercially available relay hardware.

Download or read book Fault Analysis and Model based Approach for Fault Location in Modern Grids written by Sundaravaradan Navalpakkam Ananthan and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Short-circuit faults are inevitable on transmission and distribution networks. Dispatching the maintenance crew directly to the location of the fault saves a significant amount of resources in the restoration process, which has motivated the development of several fault location approaches. Impedance-based fault location (IBFL) approaches are the most commonly used fault location methods in digital relays. However, each IBFL approach is designed specific to a line or network configuration and is not universal. Furthermore, they suffer from several sources of errors and do not fully utilize valuable information about the power system surrounding the faulted line that is available. This dissertation presents a novel fault location approach that utilizes a system model to overcome these limitations. The concept of the proposed model-based fault location (MBFL) approach is to estimate the fault location by identifying the closest match among various fault scenarios simulated using the system model and the actual fault scenario. A key benefit of the proposed approach is identifying the location of a fault on a neighboring line using limited measurements, as few as only the through fault current flowing in a neighboring line. Application methods for implementing MBFL efficiently and effectively have been developed, with each technique having its unique benefits. The advantages of the proposed MFBL approach and the practical applicability of each implementation technique have been demonstrated using simulations on complex network configurations as well as field data of fault events. This work also contributes towards tools to supplement fault analysis applications in ac and dc systems. An algorithm to select an appropriate time instant in a fault record to extract phasors for post-fault event report analysis applications was developed. In low-voltage dc distribution systems, fault signatures of series-arc faults were identified to aid arc detection. Overall, the research work presented in this dissertation makes substantive contributions to fault location and fault analysis in transmission and distribution systems

Download or read book Power System Analysis written by Charles A. Gross and published by John Wiley & Sons. This book was released on 1986 with total page 616 pages. Available in PDF, EPUB and Kindle. Book excerpt: Provides a basic comprehensive treatment of the major electrical engineering problems associated with the design and operation of electric power systems. The major components of the power system are modeled in terms of their sequence (symmetrical component) equivalent circuits. Reviews power flow, fault analysis, economic dispatch, and transient stability in power systems.

Download or read book Distribution System Modeling and Analysis written by William H. Kersting and published by CRC Press. This book was released on 2001-08-31 with total page 329 pages. Available in PDF, EPUB and Kindle. Book excerpt: For decades, distribution engineers did not have the sophisticated tools developed for analyzing transmission systems-often they had only their instincts. Things have changed, and we now have computer programs that allow engineers to simulate, analyze, and optimize distribution systems. Powerful as these programs are, however, without a real unders

Download or read book Fault Location and Analysis in Transmission and Distribution Networks written by Swagata Das and published by . This book was released on 2015 with total page 504 pages. Available in PDF, EPUB and Kindle. Book excerpt: Short-circuit faults are inevitable on transmission and distribution networks. In an effort to provide system operators with an accurate location estimate and reduce service restoration times, several impedance-based fault location algorithms have been developed for transmission and distribution networks. Each algorithm has specific input data requirements and make certain assumptions that may or may not hold true in a particular scenario. Identifying the best fault location approach, therefore, requires a thorough understanding of the working principle behind each algorithm. Moreover, impedance-based fault location algorithms require voltage and current phasors, captured by intelligent electronic devices (IEDs), to estimate the fault location. Unfortunately, voltage phasors are not always available due to operational constraints or equipment failure. Furthermore, impedance-based fault location algorithms assume a radial distribution feeder. With increased interconnection of distributed generators (DGs) to the feeder, this assumption is violated. DGs also contribute to the fault and severely compromise the accuracy of location estimates. In addition, the variability of certain DGs such as the fixed-speed wind turbine can alter fault current levels and result in relay misoperations. Finally, data recorded by IEDs during a fault contain a wealth of information and are prime for use in other applications that improve power system reliability. Based on the above background, the first objective of this dissertation is to present a comprehensive theory of impedance-based fault location algorithms. The contributions lie in clearly specifying the input data requirement of each algorithm and identifying their strengths and weaknesses. The following criteria are recommended for selecting the most suitable fault location algorithm: (a) data availability and (b) application scenario. The second objective is to develop fault location algorithms that use only the current to estimate the fault location. The simple but powerful algorithms allow system operators to locate faults even in the absence of voltage data. The third objective is to investigate the shortcomings of existing fault location algorithms when DGs are interconnected to the distribution feeder and develop an improved solution. A novel algorithm is proposed that require only the voltage and current phasors at the substation, is straightforward to implement, and is capable of locating all fault types. The fourth objective is to examine the effects of wind speed variation on the maximum and minimum fault current levels of a wind turbine and investigate the impact on relay settings. Contributions include developing an accurate time-domain model of a fixed-speed wind turbine with tower shadow and wind shear and verifying that the variation in wind speed does not violate relay settings calculated using the IEC 60909-0 Standard. The final objective is to exploit intelligent electronic device data for improving power system reliability. Contributions include validating the zero-sequence impedance of multi-terminal transmission lines with unsynchronized measurements, reconstructing the sequence of events, assessing relay performance, estimating the fault resistance, and verifying the accuracy of the system model. Overall, the research presented in this dissertation aims to describe the theory of impedance-based fault location, identify the sources of fault location error, propose solutions to overcome those error sources, and share lessons learned from analyzing intelligent electronic device data. The research is expected to reduce service downtime, prevent protection system misoperations, and improve power quality.