Power System Fault Analysis Research Articles

Principle of fault direction discrimination in near area of AC grid-connected doubly-fed wind farm

Abstract With a large number of new energy sources, the current characteristics of doubly-fed fans under the circumstances of AC grid connection short-circuit faults have become the focus of research. After crowbar resistance is put in, the attributes of short-circuit current become complicated. By calculating the correlation coefficient between the voltage of the AC system and the current of the doubly-fed fan, the fault direction can be accurately judged. In this paper, the research work for new energy power system fault analysis and protection provides a new thought and method. The current characteristics of the doubly-fed fan under fault state are analyzed deeply, and the principle of fault direction discrimination based on waveform correlation coefficient is proposed. The advantage of this method is that it is independent of fault types, and can be applied to all kinds of fault situations, with high reliability and practicability. Simulation results unveil that the principle put forward can judge the fault direction accurately, reliably, and sensitively when various types of faults occur in areas near an AC grid-connected doubly-fed wind farm.

Review of failure risk and outage prediction in power system under wind hazards✰

Given that wind hazards pose a considerable damage to power system in various countries, researchers have developed methods for disaster prevention to diminish the vulnerabilities. This paper attempts to review the failure analysis procedure under the impact of wind hazards, considering the following attributes: wind field generation method, wind-induced electrical component failure model in transmission system, and building outage prediction model from data-driven view in distribution system. First, we compare the calculation of circulation and translation wind speed, with geographical, temporal and uncertainty factors of wind speed considered. Then, we introduce the wind-induced component failure models derived by wind load calculation and fragility curves. The application of the series reliability model in multiple cluster failures is briefly described. Finally, we summarize the applications of data analysis in building outage prediction models. The reviewed literature contains the statistical learning methods and machine learning methods. It is concluded that the frameworks for component-level failure model and user-level outage prediction model are well established. However, most of the studies still develop two models, separately. Future researchers may target at the hybrid application of both models to better provide fault analysis, prediction and emergency in power system under wind hazards.

Optimally detecting and classifying the transmission line fault in power system using hybrid technique

In this paper, a hybrid system is proposed to predict and classifies the power system transmission line faults. The proposed technique is the consolidation of both the truncated singular value decomposition (TSVD) and Human urbanization algorithm (HUA) based Recurrent Perceptron Neural Network (RPNN), and hence it is named as TSVD-HUARPNN technique. TSVD is matrix decomposition, this technique qualify the outcome it as fast or not. In the proposed work, the qualification of the results from the TSVD is improved by a lemma theorem; it is a proven proposition which is used to obtain a larger and optimal result. For that reason, it is also known as a ”helping theorem” or an ”auxiliary theorem”. Here, it has two modules for power system fault analysis: (i) fault detection, (ii) fault classification. The first process of the proposed system is the generation of the dataset of normal and abnormal conditions of transmission line parameters of power system using TSVD. The extracted dataset is assessed by HUA-based RPNN system to classify the fault analysis that occurs in transmission system. The TSVD-HUARPNN system is used to predict and classify the fault present in the transmission line. The proposed TSVD-HUARPNN system ensures the system with less complexity for the detection and classification of the fault, therefore the accuracy of the system is increased. By then, the proposed model is activated in MATLAB/Simulink, its performance is evaluated with the existing models. The performance with noise at 20 dB of the proposed technique is 99.77%.

Research on thermal imaging fault detection system based on weibull distributed electrical system

A fault prediction analysis is performed In order to use infrared thermal imaging technology to detect electrical system faults, based on Weibull distribution technology. First, the principle is explained, the key technologies and factors of infrared thermal imaging and the electrical fault monitoring system are analyzed, and the available technologies are summarized. The detection process and analysis research are established with the help of on-site inspection and analysis results for power system fault analysis and research. The research shows that the method is effective for fault detection and trend analysis, and provides a reference for power fault detection and prediction analysis.

Modelling and Fault Current Characterization of Superconducting Cable with High Temperature Superconducting Windings and Copper Stabilizer Layer

With the high penetration of Renewable Energy Sources (RES) in power systems, the short-circuit levels have changed, creating the requirement for altering or upgrading the existing switchgear and protection schemes. In addition, the continuous increase in power (accounting both for generation and demand) has imposed, in some cases, the need for the reinforcement of existing power system assets such as feeders, transformers, and other substation equipment. To overcome these challenges, the development of superconducting devices with fault current limiting capabilities in power system applications has been proposed as a promising solution. This paper presents a power system fault analysis exercise in networks integrating Superconducting Cables (SCs). This studies utilized a validated model of SCs with second generation High Temperature Superconducting tapes (2G HTS tapes) and a parallel-connected copper stabilizer layer. The performance of the SCs during fault conditions has been tested in networks integrating both synchronous and converter-connected generation. During fault conditions, the utilization of the stabilizer layer provides an alternative path for transient fault currents, and therefore reduces heat generation and assists with the protection of the cable. The effect of the quenching phenomenon and the fault current limitation is analyzed from the perspective of both steady state and transient fault analysis. This paper also provides meaningful insights into SCs, with respect to fault current limiting features, and presents the challenges associated with the impact of SCs on power systems protection.

Fault analysis in power system using power systems computer aided design

<span>This work presents a fault analysis simulation model of an IEEE 30 bus system in a distribution network. This work annalysed the effect of fault current and fault voltage in a distribution system. A circuit breaker was introduced into the system to neutralize the effect of the fault. The system was run on a PSCAD software and results were obtained. The system was monitored based on the start time and the end time of the fault and how well the circuit breaker reacts with those times. Fault occurred from 0.100 to 0.300 seconds before it was removed. At the time fault was not applied (i.e. from 0.00 to 0.100 and from 0.300 to 0.72), the circuit breaker was close and became open when fault was applied so as to cut off current flow through the line.The result obtained gave the disruption caused by the fault and the quick response of the circuit breaker in neutralizing it. Results gotten are based on when the circuit breaker is close and no fault is applied and when the circuit breaker is open due to fault. From this work, it was obtained that circuit breakers are very essential in system protection and reliability.</span>

Fault Analysis of Electric Power System using PLC and Wireless Communication System

In present scenario electricity theft is the major hurdle in front of government. This paper comprises of functions and architecture of the smart metering and monitoring network system which works on real time data communication and have its own network. Our main motive is to design and develop such a wireless metering system which will prevent power theft and provide us a reliable and accurate metering monitoring system by using modern technology. The design comprises of wireless power metering and monitoring network which will work on principle of real time data communication(which is not available in existing wireless GSM metering system) and will use its own reliable network with the help of Programmable Logic Controller. Programmable Logic Controller, smart meters, wireless communication modules and profinet cable are the key components of the system. To provide a better and easy human interface with the smart meter we are using simplify S CADA and programming which is very user affable.

A new intelligent scheme for power system faults detection and classification: A hybrid technique

AbstractThis paper proposes a hybrid technique to detect and classify the transmission line faults in the power system. The proposed approach is the joint execution of linear discriminant analysis (LDA) and cuttlefish optimizer (CFO) learning process‐based random forest algorithm (RFA), ie, named as LDA‐CFRFA technique. Here, two modules are utilized for fault analysis in power system: fault detection and fault classification. The first procedure of the proposed method is the power system transmission line parameters in normal and abnormal condition dataset preparation by using LDA. LDA‐based dataset preparation process consists of feature extraction of power flow parameters and defines the nature of signals occurred by the system. The extracted dataset is assessed by CFO‐based RFA technique for classifying the fault type occurred in the transmission system. By then, the proposed model is executed in MATLAB/Simulink working stage, and the execution is assessed with the existing techniques such as CFO, RFA, Feed forward neural network (FNN), and artificial neural network (ANN). In our research, the faults implemented on test system are phase A, phase B, phase C, phase A to ground (AG), phase B to ground (BG), phase C to ground (CG), phase AB, phase AC and phase BC, phase AB to ground (ABG), phase AC to ground (ACG), and phase BC to ground (BCG). From the results, the proposed technique guarantees the system with less complexity and less consumption time for the detection and classification of the fault, and hence, the accuracy of the system is increased.

Dynamic analysis of multi‐machine multi‐UPFC power systems experiencing transient asymmetrical faults

A new method for studying the transient asymmetrical shunt and series faults in multi-machine multi-unified power flow controller (multi-UPFC) power systems is proposed. Considering an arbitrary shunt or series fault in a power system, the method uses a combination of space phasors-based sequence networks corresponding to the fault. Synchronous machines and UPFCs are modelled via injecting sequence current phasors. The quasi-static Y-matrix equations of the network are solved first, to obtain the sequence voltages of the terminal bus-bars of synchronous machines. Then, these voltages are used to solve the non-linear equations of the machines (in the rotors d-q reference frames) in the subsequent step time (). This procedure is repeated until a steady-state condition is reached in the post-fault condition. The proposed method for fault analysis has high processing speed and acceptable accuracy, which is very important for online protection and control computations. Based on the proposed method, a computer program has been developed that is applicable for the fault analysis of modern or conventional power systems with any size. The performance of the proposed method is studied by some simulation results and compared with other similar works. The simulation results very well support the accuracy and efficiency of the method.

MCDM approach for the integrated assessment of vulnerability and reliability of power systems

Fault analysis of modern power systems cannot be only addressed on classical reliability techniques but also considering the impact of cascading failures. This paper proposes an original integrated approach for the risk management of a power system subject to random contingencies by using vulnerability and reliability quantitative measures. Five different systems based on the IEEE-RTS have been studied from the vulnerability and reliability perspectives. According to the calculation carried out and the Multi-Criteria Decision Making (MCDM) method applied to better consider the integration of both concepts, the vulnerability and reliability perspectives are complementary viewpoints that can help to design a more robust critical infrastructure.

Analysis of Fault Harmonic in Electrical Power System Based on Improved Particle Swarm Optimization Algorithm

To estimate the parameters of fault harmonics in electrical power system more accurately and control the harmonic pollution, an improved Particle Swarm Optimization (PSO) algorithm is proposed. The traditional PSO algorithm has been improved, the problem of harmonic estimation is transformed into a minimum optimization problem, and the harmonic parameter optimization algorithm based on improved PSO and least square method is proposed, and corresponding simulation examples and measured data are created in matrix laboratory (MATLAB). The results show that the algorithm is not only accurate, but also has the advantages of anti-gaussian white noise and processing interharmonic. The proposed algorithm has potential application in harmonic fault analysis of electrical power system.

An improved averaged value model of MMC-HVDC for power system faults simulation

Detailed model (DM) of modular multilevel converter (MMC) brings about a high computational burden for electromagnetic transient (EMT) simulation. Therefore averaged value model (AVM) of MMC is proposed for fast simulation of large-scale multi-terminal HVDC system. No direct electrical contact exists between AC and DC system in conventional AVM and therefore the coupling relationship among electric quantities in fault analysis could not be accurately modelled. In order to solve the aforementioned problem, an improved AVM (IAVM) of half-bridge (SB) MMC topology is proposed. All capacitor voltages of AVM are constant and an arm is directly equivalent to a controlled voltage source. The proposed AVM can be applied for the DC faults and blocking conditions by introducing a group of switches connecting AC and DC sides. Two extra controlled voltage sources are introduced for correct DC voltage offset in AC voltages under DC line-to-ground (LTG) faults. Simulation results verify the accuracy and efficiency of the IAVM. IAVM could be implemented in commonly used software packages and is suitable for power system fault analysis.

Phasor Estimation and Modelling Techniques of PMU- A Review

Abstract The values of voltage / current signal at various places in a power network are measured by Phasor Measurement Unit(PMU). The PMU's work on the phasor values of the data collected using Phasor estimation technique. This mechanism is essential for analysis and interpretation of collected data in a correct manner. Therefore, a Phasor estimation process has a lot of importance in design of control mechanism and various protection systems to be implemented. Numbers of PMUs are being installed across the world for different applications such as post fault analysis, state estimation and protection of power system. Since the cost of PMUs is very high, they are placed optimally in the power system such that complete power system is observable. In this study, PMU along with techniques used for phasor measurement has been reviewed. Some of the used phasor estimation techniques viz. zero crossing, DFT and SDFT are described to compute magnitude and phase value of input signal.

Study on Power Flow Calculation Using PSASP

The power flow calculation is a basic electrical calculation which is to study the steady state operation of power system. Its task is to decide the whole system running state according to the given operating conditions and the network structure. The power flow calculation is the basis of the stability calculation and fault analysis of power system. In this paper, through a four machine 11 node example, we shows that the influence of generator node type on power flow calculation.

지중 송전선로 대칭분 임피던스 해석을 위한 EMTP 전후처리기 개발과 활용

Power system fault analysis has been based on symmetrical component method, which describes power system elements by positive, negative and zero sequence impedance. Obtaining accurate line impedances as possible are very important for estimating fault current magnitude and setting distance relay accurately. Especially, accurate calculation of zero sequence impedance is important because most of transmission line faults are line-to-ground faults, not balanced three-phase fault. Since KEPCO has started measuring of transmission line imepdance at 2005, it has been revealed that the measured and calculated line impedances are well agreed within reasonable accuracy. In case of underground transmission lines, however, large discrepancies in zero sequence impedance were observed occasionally. Since zero sequence impedance is an important input data for distance relay to locate faulted point correctly, it is urgently required to analyze, detect and consider countermeasures to the source of these discrepancies. In this paper, development of pre/post processor to ATP (Alternative Transient Program) version of EMTP (Electro-Magnetic Transient Program) for sequence impedance calculation was described. With the developed processor ATP-cable, effects of ground resistance and ECC (Earth Continuity Conductor) on sequence impedance were analyzed.

지중송전선로의 대칭분 임피던스 모델링에 관한 연구

Power system fault analysis is commonly based on well-known symmetrical component method, which describes power system elements by positive, negative and zero sequence impedance. The majority of fault in transmission lines is unbalanced fault, such as line-to-ground faults, so that both positive and zero sequence impedance is required for fault analysis. When unbalanced fault occurs, zero sequence current flows through earth and groundwires in overhead transmission systems and through cable sheaths and earth in underground transmission systems. Since zero sequence current distribution between cable sheath and earth is dependent on both sheath bondings and grounding configurations, care must be taken to calculate zero sequence impedance of underground cable transmission lines. In this paper, EMTP-based sequence impedance calculation method was described and applied to 345㎸ cable transmission systems. Calculation results showed that detailed circuit analysis is desirable to avoid possible errors of sequence impedance calculation resulted from various configuration of cable sheath bonding and grounding in underground cable transmission systems.

Design of an Overvoltage Online Monitoring Device Based on Optical Fiber Voltage Sensor

An overvoltage online monitoring and data analysis device based on optical fiber voltage sensor is designed. The device adopts BGO crystal as sensing head, optical fiber as transmission medium. Four A/D converters with sampling rate of 20 MHz are equipped in Data acquisition unit to achieve four-channel concurrent high-speed data acquisition. Virtual instrument LabVIEW is used to complete data analysis and processing. Compared with other voltage monitoring device, it has good anti-interference performance and fast transient response. Physical simulation experiments prove that the system can meet the requirements of overvoltage monitoring. Its application provides accurate data for power system fault analysis and insulation coordination design.

Improved Apriori Algorithm in the Power System Fault

For the low efficiency in generating candidate item sets of apriori algorithm, this paper presents a method based on property division to improve generating candidate item sets. Comparing the improved apriori algorithm with the other algorithm and the improved algorithm is applied to the power system accident cases in extreme climate. The experiment results show that the improved algorithm significantly improves the time efficiency of generating candidate item sets. And it can find the association rules among time, space, disasters and fault facilities in the power system accident cases in extreme climate. That is very useful in power system fault analysis.

A Fault Analysis of 11kv Distribution System (A Case Study of Ado Ekiti Electrical Power Distribution District)

The aim of this research work is to carry out fault analysis of 11KV distribution power system. Electric power is an essential facilitator for sustainable development of the modern nation state. While Nigeria is reported to suffer from severe shortages of electric power the condition of some of its newer constitutional units are unknown. In this work, electric power infrastructure and energy availability is studied for Ado-Ekiti, the principal economic and political hub of Ekiti State. During the study, the condition of all relevant equipment for power distribution at the 11 kV level was assessed. Power availability was also considered by collecting necessary data that had to do with energy supplied, faults and other outages. It was discovered that the distribution lines were in a rather poor state with as many as 25% of the poles not meeting a condition of goodness, 33% of cross-arms being broken or unsatisfactory, about 10% of the insulators defective and almost 40% of the span not complying with standards. Hence this work presents a research on fault analysis of Ado Ekiti distribution power system.

A Methodology for Computational Efficiency Improvement of Z-Matrix in Power System Fault Analysis Using Evolutionary Algorithms

This study presents a novel and comparative approach to select an optimal path during direct Z-Matrix building process using Evolutionary Algorithms (EAs). The proposed evolutionary methods are based on selection of series and shunt elements (i.e., lines, transformers and generators) in optimal order for minimizing computation time. The proposed evolutionary methods are tested on IEEE 14-bus benchmark and the results are compared. The proposed method is also arranged to find the optimal path considering all possible network alterations due to all possible faults to avoid the requirement for repeating the calculation process for each single line fault. The comparative results indicate the feasibility and effectiveness of the method to find the optimal path in Z-matrix building process and considerably diminishing the time consumption for Z-matrix modification.