Power system faults

In this paper, power quality improvement by using a new structure of non superconducting fault current limiter (NSFCL) is discussed. This structure prevents voltage sags on Point of Common Coupling (PCC) just after fault occurrence, because of its fast operation. On the other hand, previously used structures produce harmonics on load voltage and have ac losses in normal operation. New structure has solved this problem by using dc voltage source. The proposed structure is simulated using PSCAD/EMTDC software and ...

This paper reports the digital-time domain and frequency domain studies on a typical 132kV Capacitor Voltage Transformer (CVT) model. The transient studies are conducted using Alternative Transient Program (ATP-EMTP). Simulation results corresponding to the CVT transient response under both system fault and ferroresonance condition are reported in this paper. Transient studies are performed (1) to identify the CVT components that contribute to the transient response of CVT, (2) to determine system condition that affect the CVT transient response. A lightning simulation case study is also presented. © 2006 IEEE.

http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=4154549

Black out means complete shutdown of electrical network due to some circumstances. A large scale power failure or power outage for a certain amount of time happens due to blackout. Black out is a huge threat for power system engineers since it cause huge obstacle and financial losses in human life and utilities. So, blackout must be prevented for the welfare of human and society. Therefore, black out prevention methodologies is a burning topic of research now days. In this paper, a study has been carried out on blackout. Specially different blackout phenomena across the globe, the causes behind the blackout and different black out prevention methodologies and their advantages and disadvantages are discussed. Among the blackout prevention methodologies auto-load shedding scheme, intelligent islanding scheme and hybrid scheme are thoroughly studied. Importance of critical element protection is also discussed. The power world simulation diagrams with simulator version 18, under critical elements under contingency with an IEEE-14 bus test system are also shown in this context. Results of frequency fluctuations with graph also shown in the paper. Instead of using any single particular method, hybrid method is suggested for getting better blackout prevention result is suggested at the end with a hope that it will be useful for power system engineers.

The occurrence of faults in any operational power system network is inevitable, and many of the causative factors such as lightning, thunderstorm among others is usually beyond human control. Consequently, there is the need to set up models capable of prompt identification and classification of these faults for immediate action. This paper, explored the use of artificial neural network (ANN) technique to identify and classify various faults on the 11 kV distribution network of University of Lagos. The ANN is applied because it offers high speed, higher efficiency and requires less human intervention. Datasets of the case study obtained were sectioned proportionately for training, testing, and validation. The mathematical formulations for the method are presented with python used as the programming tools for the analysis. The results obtained from this study, for both the voltage and current under different scenarios of faults, are displayed in graphical forms and discussed. The resu...

The paper discusses issues related to integration of substation IED data. The approach to discussion is based on the purpose of integrating substation data and how the integrated data can be used. Main reasons for substation data integration can be categorized into following groups: 1) data archival and exchange purposes, 2) easy access and viewing, and 3) data analysis. The paper identifies issues important for proper substation data integration: 1) handling system configuration information, 2) automated and straightforward communication, and 3) data file formats. Modern substations may be equipped with different types of intelligent electronic devices (IEDs) such as digital protective relays (DPRs), digital fault recorders (DFRs), phasor measurement units (PMUs), power quality monitors (PQMs), digital revenue meters (DRMs), etc. It is an engineering challenge to design and implement automated data integration and analysis systems today since most of the above mentioned issues are addressed through use of vendor-specific solutions, which are quite different from one vendor to another. The paper gives an overview of the options how existing vendor solutions may be combined with standards and recommendations to enable feasible means for easy and proper use of substation data. The discussion is followed by an example of an existing substation data integration system.

This paper presents an analysis in Matlab/ Simulink environment of a three-phase photovoltaic (PV) system under various types of symmetrical and asymmetrical grid faults. The fault response performance of the PV system takes into consideration the factors of ambient temperature and solar irradiance, grid codes, power control strategies, and utility grid conditions. Grid fault types occurring at different distances from the point of common coupling (PCC) of the PV system are simulated. The simulations presented in this paper show that the short circuit faults in the power grid have disturbing effects on optimal operation of grid-connected PV systems. The impact of grid faults on the PV systems performance depends on the grid fault type, and is less influenced by the distance of the fault occurrence. Symmetrical faults have a higher impact on performance than asymmetrical faults, both at the PCC and inside the PV system.

The paper focuses on new concepts in automating analysis of all the IED data recorded in substations. It addresses the main requirements for enabling integration of existing and deployment of new analysis functions. New concept also enables combining the use of integrated IED data with other useful tools for system troubleshooting such as advanced digital simulators. Automated analysis of integrated data collected from different types of IEDs is a first step towards new solutions that will dramatically reduce the time needed for restoration after systemwide disturbances. Importance of a transparent system configuration database and ability to match measured data collected from IEDs to their corresponding system components is discussed through example requirements for new functions. Several utilities are taking steps to automating the process of data collection and analysis and integrating both measurements and system configuration data. The paper introduces some of the existing solutions as well as the solutions that are currently being developed.

Many techniques used and still in usage for solving the problem of islanding detection are intrinsically passive, active, or hybrid of both. Each one of them has its own benefits and drawbacks. In this paper, we propose a method, which takes the advantage of a machine learning (ML)-based algorithm, namely, support vector machine (SVM), in order to produce the results more efficiently. The results of the simulations based on the model and experimentally measured parameters of a real-life practical photovoltaic (PV) plant give much better output than the traditional reported methods. During the tests and simulations, an additional problem, namely, grid fault, emerged, posing new challenges for the proposed method. Occurrences of islanding and grid fault are grouped together with the same kernel dimension and no custom hyperplane bordering. Discrimination between islanding and grid fault events is an essential dilemma, which is handled by the proposed SVM-based algorithm to achieve more precision in islanding detection and simultaneously detect the grid faults authentically. Nondetection zones (NDZs) and detection time (DT) are tested using two dimensions, namely, the generated active energy from PV plant (0%-110% of P n) and distribution network voltage levels (±10% of U n). Simulations based on the model and parameters of a real-life practical PV power plant are performed in MATLAB/Simulink environment, and several tests are executed for several scenarios. Finally, comparisons with previously reported techniques prove the effectiveness, authenticity, selectivity, accuracy, and precision of the proposed islanding and grid fault detection strategy with allowable impact on power quality according to UL1741 and its superiority over other methods.

Test case prioritization techniques basically schedule the execution of test cases in a definite order such that to attain an objective function with greater efficiency. This scheduling of test cases improves the results of regression testing. Test case prioritization techniques order the test cases such that the most important ones are executed first encountering the faults first and thus makes the testing effective. In this paper an approach is presented which calculates the product of statement coverage and function calls. The results illustrate the effectiveness of formula computed with the help of APFD metric.

This paper addresses some new approaches to data integration and information exchange that are made possible due to the use of advanced Information Technology (IT). As a result, some traditional applications such as fault analysis can be significantly enhanced and automated. Paper first describes how the functional enhancement and automation of fault analysis may result in faster system restoration, better quality of power delivery, and more comprehensive preventive maintenance actions. The paper illustrates how in the competitive utility environment this leads to improved service and ultimately better customer satisfaction while maintaining and even reducing operational cost. Several examples related to automated fault analysis are described as follows: disturbance analysis, analysis of Circuit Breaker (CB) operation, and fault location analysis using sparse field data. INTRODUCTION Deregulation, liberalization, restructuring and privatization in the utility industry are simultaneously happening around the globe. They represent different approaches to making the utility industry more cost effective and responsive to customer needs. As a result, two important trends are recognized: the introduction of more automated functions and the use of more advanced information technology. The final aim is to provide better service to the customers and to reduce the operating cost. This paper illustrates how the existing fault analysis approach can significantly be enhanced through the use of advanced information technology [1]. In this context, the information technology relates to the technology for communications, processing, intelligent systems, computer networks, databases, user interfaces, etc. First, the application functions can be improved to include broader view of the analysis including data from multiple intelligent electronic devices (IEDs). This leads to a comprehensive data integration resulting in efficient data processing. Once the relevant information is extracted, it can be distributed to multiple users responsible for maintaining the quality and reliability of the energy supply service. All of this can easily be automated using information technology services embedded in the applications.

Automation of fault analysis is a desirable future application due to “explosion” of on-line substation data collected during disturbances. Analyzing this data manually is just not feasible; automation of the analysis is necessary. This paper focuses on three options for implementation of automated fault analysis based on: a) uses of individual Intelligent Electronic Devices such as Digital Fault Recorders (DFRs), Digital Protective Relays (DPRs), Sequence of Events Recorders(SERs), etc, b) integrated substation automation systems with all Intelligent Electronic Devices (IEDs) interconnected, and c) integrated
enterprise monitoring and control system including Supervisory Control and Data Acquisition (SCADA) Remote terminal units (RTUs) combined with other substation IEDs. For each of the approaches, implementation requirements are discussed and possible benefits are outlined.

Information systems and intelligent smart grid data analytics will have a critical role in managing the massive amount of data becoming available in power system substations. Digital protective relays are multi-functional intelligent electronic devices based on microprocessors, which are being installed in substations throughout the power grid. New digital relays are replacing old-fashioned electro-mechanical or solid-state relays, and besides their protective function, they are coming equipped with monitoring capabilities. These monitoring capabilities are creating potential for better observability of power systems, redundancy in measurements, and improved decision-making process when operating the system. This article discusses the implementation requirements for a fully automated data analytics solution that provides data integration, fault analysis, and visualization based on the event data recorded by digital protective relays.

Transmission line fault detection is an important aspect of monitoring the health of a power plant since it indicates when suspected faults could lead to catastrophic equipment failure. This research looks at how to detect generator and transmission line failures early and investigates fault detection methods using Artificial Neural Network approaches. Monitoring generator voltages and currents, as well as transmission line performance metrics, is a key monitoring criterion in big power systems. Failures result in system downtime, equipment damage, and a high danger to the power system's integrity, as well as a negative impact on the network's operability and dependability. As a result, from a simulation standpoint, this study looks at fault detection on the Trans Amadi Industrial Layout lines. In the proposed approach, one end's three phase currents and voltages are used as inputs. For the examination of each of the three stages involved in the process, a feed forward neural network with a back propagation algorithm has been used for defect detection and classification. To validate the neural network selection, a detailed analysis with varied numbers of hidden layers was carried out. Between transmission lines and power customers, electrical breakdowns have always been a source of contention. This dissertation discusses the use of Artificial Neural Networks to detect defects in transmission lines. The ANN is used to model and anticipate the occurrence of transmission line faults, as well as classify them based on their transient characteristics. The results revealed that, with proper issue setup and training, the ANN can properly discover and classify defects. The method's adaptability is tested by simulating various defects with various parameters. The proposed method can be applied to the power system's transmission and distribution networks. The MATLAB environment is used for numerous simulations and signal analysis. The study's main contribution is the use of artificial neural networks to detect transmission line faults.

The occurrence of faults in any operational power system network is inevitable, and many of the causative factors such as lightning, thunderstorm among others is usually beyond human control. Consequently, there is the need to set up models capable of prompt identification and classification of these faults for immediate action. This paper, explored the use of artificial neural network (ANN) technique to identify and classify various faults on the 11 kV distribution network of University of Lagos. The ANN is applied because it offers high speed, higher efficiency and requires less human intervention. Datasets of the case study obtained were sectioned proportionately for training, testing, and validation. The mathematical formulations for the method are presented with python used as the programming tools for the analysis. The results obtained from this study, for both the voltage and current under different scenarios of faults, are displayed in graphical forms and discussed. The resu...

This paper gives an overview of future requirements for fault and disturbance analysis. Special attention is given to the issues of the extent of analysis, data integration, information exchange, speed of processing, database needs, dissemination of analysis results and related user interface, and support through existing and new standards. Selecting implementation options and moving towards more integrated solutions are discussed and supported with a summary of the existing relevant standards as well as the need for defining new ones. Examples of the most advanced solutions deployed by the utility companies are given as well.

The paper discusses a concept of substation data integration for implementation of new automated analysis functions. Proper data integration is the main requirement to enable automation of the analysis and its future extensions. The integrated data concept is making the whole solution transparent to adding new types or product versions of IEDs, as well as new analysis functions. There are several types of modern IEDs used in today's substations. Different file formats and data collection strategies are implemented by different vendors. The paper addresses the issue of integrating IED data recorded by different IED types and then focuses on how to facilitate the use the integrated data. Several new analysis functions can be performed on the collected IED data and the results of the analysis can serve different groups of utility users. The paper introduces examples of automated analysis functions configured using the proposed concept for integration of IED data. The solution is open for adding new analysis functions that can utilize both the integrated IED data and the processing (analysis) results from other automated analysis functions. The analysis functions, system configuration, and the whole concept of data integration are evaluated using digital power system simulator.

The paper discusses substation IED data integration and its importance for implementation of automated analysis solutions. Recorded data collected from various substation IEDs is stored into a substation data mart that utilizes standardized file formats and a database interface. The data mart provides a foundation for multiple uses of substation data. Utilities are faced with a challenge of how to bring together internal needs and requirements, available standards, and recommendations developed by professional organizations, as well as the requirements imposed externally (i.e. NERC standards). Sometimes, there is a challenge of understanding what to expect from solutions that implement all those requirements.
In this paper a data mart implementation concept for automated integration and analysis of substation is given first. The solution and implementation requirements are discussed through realistic examples and evaluation of the solution with a variety of test data. Evaluation examples are based on both simulated fault data as well as the actual fault disturbances captured in field by substation IEDs. The presented test examples illustrate what can be expected from substation data mart based solution for automated analysis and how such a solution can be further expanded.

The paper focuses on deployment challenges for automated substation data analysis solutions. Through examples from recent deployment projects, the paper discusses the fact that both the utilities and suppliers are dealing with a set of requirements defined as a compromise between the needs of variety of in-house stakeholders. These requirements are prone to changes and that itself is one of the biggest challenges. In addition, the deployment is almost always faced with unexpected challenges from the production environment itself. The paper illustrates a gradual step-by-step approach from a solution demonstration to the production deployment. The first part focuses on the solution that analyzes digital fault recorder and digital protective relay data. In-house testing with both simulated data and with the data obtained from the field is discussed. The second part of the paper discusses implementation and deployment of a new circuit breaker recorder aimed at on-line monitoring circuit breaker operations.