Phase Short Circuit Fault Research Articles

Characteristics of symmetrical components for high impedance faults in distribution networks with photovoltaic inverters

This work models a photovoltaic (PV) inverter connected to an IEC microgrid system. The purpose of this study was to find the characteristics of symmetrical components before and after a high impedance single phase short-circuit fault. The IEC microgrid system is tailored to the distribution system in Indonesia, where the applied voltage is 20 kV. Only parameters related to the short-circuit study are included in the model. A second-order generalized integrator frequency-locked-loop is utilized to represent the 3-phase PV inverter. The inverter model, previously treated as an ideal current source, and positive sequence current are no longer employed, as they fail to depict the characteristics of symmetric components during a phase-to-ground short-circuit fault. The IEC microgrid system connected to the PV inverter is simulated using ATPDraw-electro magnetic transient program (EMTP). Simulation results reveal that the changes in the symmetric component values of current after a fault experience a very insignificant increase. Meanwhile, the positive sequence voltage values following the short-circuit fault exhibit a negligible decrease. In contrast, the negative sequence and zero sequence voltage components after the short-circuit fault undergo a significant increase.

Voltage Regulation in Power Distribution System using Dynamic Voltage Restorer

In the entire power system we are having different levels of voltages. The voltages are depending on the Generation, Transmission and Distribution. In this Different levels the sudden changes of voltages are occur due to various reasons. But the voltage changes at distribution shows the impact on consumers. So to protect the consumers from sudden voltage changes the DVR technique is used. Which is the most popular technique and it gives the best results, here we are taking induction motor as a load for voltage changes three phase short circuit faults are taking. In this paper the proposed system has been modeled and simulated using the MATLAB/SIMULINK environment and simulation results discussed

A machine learning-based fault identification method for microgrids with distributed generations

The development of renewable energy sources such as solar and wind based on distributed generators are growing rapidly in the face of the global energy crisis. As a connection between distributed generation and the main grid, microgrids are also growing rapidly. However, due to the randomness and uncertainty of the output of the solar and wind power, as well as the bidirectional characteristic of current flow, the faults in microgrids are difficult to identify using the traditional fault detection methods. To address this problem, this paper proposes a machine learning-based fault identification method for microgrids. First, the modified K-means algorithm is implemented to cluster the voltage data. Then, FP-growth algorithm is using to extract the association rules. Third, the mini-batch gradient descent (MBGD) algorithm is using to train the fault identification model based on machine learning theory. To verify the validity of this method, a case study considering single-phase short-circuit fault and two-phase phase short-circuit fault is simulated. The method presented in this work is with a high accuracy according to the simulation results.

Impact of 5 MWp Solar Power Plant Interconnection on Power Flow and Short Circuit Interruption in the 20 kV Medium Voltage Network at Area X Power System

One example of the application of new renewable energy that is currently developing is solar power plant. Based on data from Rencana Usaha Penyediaan Tenaga Listrik (RUPTL) PT PLN (Persero) 2019-2028, it is stated that the potential of solar energy in Indonesia is 207,898 MW (4.80 kWh / m2 / day) and only 78.5 MW of capacity installed in Indonesia. In this study, a 5 MWp solar power plant was interconnected with a 20 kV medium-voltage network of Area X as one of the renewable energy applications in Indonesia. Interconnection studies include power flow analysis and three phase short circuit fault analysis. In the analysis of the power flow results obtained that the Solar Power Plant system is capable of supplying the load requirements to the system of 5,000 kW active power. It was also found that interconnection of solar power plant with the system resulted in an increase in the voltage level of each bus in the system by 0.08 to 1.41%, as well as changing the percentage of component loading by 0.01% -93.01%. The results of the three-phase short-circuit fault analysis show that the interconnection of the solar power plant system has a short-circuit fault current value of 5.70-7.01 kA, so the fault current value for the whole bus is still far below the value of the short-circuit current capacity of the protection system's short circuit worth 25 kA. The results of the interconnection study showed that interconnection of a 5 MWp solar power plant system with a 20 kV medium voltage network Area X can be carried out.

Improved Method of Local Feeder Automation Considering Small Hydro-power Connection

With the access of small hydro-power stations (SHS), the distribution system presents a multiple power supply pattern, which has a negative impact on the original local feeder automation (LFA) which is suitable for single side power supply system. In view of this effect, the phase to phase short-circuit fault (PPF) and single-phase grounding fault (SPGF) are treated differently, and an improved LFA method (IMLFA) considering SHS’s access based on low-frequency load shedding (LFLS) and high-frequency generator tripping (HFGT) is proposed. In case of SPGF, the section switch (SSW) and the outgoing circuit breaker of the substation shall be opened in sequence, and the isolated network (IN) generated in the process can be operated stably by cooperating with LFLS or HFGT while the fault is preliminary isolated. The SSW and the breaker are added with the function of no-voltage detection and synchronization detection. In case of instantaneous fault, the power supply in the fault area can be restored after a series of operations, and the IN can be connected to the grid. If it is a permanent fault, the section switches (SSWs) around the fault area will be locked to close in order to isolate the fault effectively, and the IN, not separated by the fault area from the grid, can be connected to the grid. Analysis and simulation show that the method is correct and feasible.

10 kV AC test verification of the high temperature superconducting fault current limiter with bias magnetic field

Under the support of the China State Grid Corporation Science and Technology Project, a set of 10 kV superconducting fault current limiter (SFCL) with bias magnetic field including a high temperature superconducting a low inductance unit, a double split reactor, a fast breaker and its control system is designed and assembled in Hushitai high voltage center of Electric Power Research Institute of State Grid Liaoning Electric Power Co., Ltd. The 10 kV dedicated test including high voltage test, phase to phase short circuiting fault test, quench resistance measurement, quench recovery time measurement were performed in December 2019. The fault current distribution and voltage test results during the phase to phase short-circuit fault of the SFCL are presented and analyzed. Test results indicate that current limiting resistance of SFCL unit is about 1.21 Ω within 10 ms fault time. Those results meet the design requirement.

Analysis of the impact of distributed generation injection to stability of 20 kV distribution network system

This study took a case study at PT. PLN (Persero) APJ Area Bandung with the subject raised is the installation of Distribution Generators on the distribution line of 20 kV. The purpose of this study was to determine the effect of generator installation Distribution of stability on a system of 20 kV distribution with load conditions is considered balanced. The reason for conducting this research is to find out how far DG can maintain stability on each bus. The method used in this study is to compare the results of the simulation of power flow and short circuit interference using ETAP Power System software. The results obtained from the power flow simulation before installation DG voltage drop at the end of the line. While the three phase short circuit fault current before the DG installation at the beginning of the line is x. After installation of DG with an injection of 50% power DG obtained a voltage drop at the end of the line of y and a fault current at the beginning of the line of z. While the injection of 90% of the power obtained by the voltage drop at the end of the line is v and the fault current at the beginning of the line is w. The results of the study show that with the injection of DG can increase the voltage profile on the line. Likewise, the interference current has increased, but it can be overcome by placing the location of the DG from the fault site.

Effect of Distributed Wind Generation on the Voltage Sag of Distribution Networks

As the issue of global warming is worsening, the shift towards using renewable energy resources is becoming more of an obligation rather than an option. With the continual decline in the cost of distributed small and medium-scale renewables and government sponsored programs, the outlook of growth of these converter-based resources remain high. Renewable energy resources are connected at the end-user terminals, in close proximity to the load at the distribution network. Such connection in the locale brings perceived benefits of transmission loss reduction, increased energy efficiency and improved voltage regulation. Yet, distributed renewable generation have noticeable effects on system’s power quality. This paper investigates the impacts of distributed wind generation on the voltage sag of distribution systems. A systematic approach is constructed to capture voltage sag occurrence incidents, due to wind generation connected at distribution nodes, and trigger the dynamic voltage restorer (DVR) into active operation mode to rectify the voltage sag problem. A test feeder system is represented using MATLAB/Simulink with wind turbines connected at several nodes of the system. A model for the DVR is developed in Simulink. It was then integrated with the test feeder system. Simulation results show that the incorporation of increased proportions of wind generation into the distribution network may give rise to negative operating conflicts as far as the voltage sag is concerned. Results manifest that the DVR is capable of effective correction of the voltage sag, caused by a three phase short-circuit fault, in presence of high penetration levels of variable wind generation connected at disparate locations in the distribution network.

ANALISIS PENENTUAN SETTING DISTANCE RELAY PENGHANTAR SUTT 150 KV GIS PESANGGARAN – GI PEMECUTAN KELOD

The addition of UGC cable (Under Ground Cable) and equipment rating’s change for the reconfiguration from Air Insulated Swichgear into Gas Insulated Switchgear at Pesanggaran substation. Therefore need to reset distance relay settings so that relays can work more selectively and reliably. Using manual and simulation calculations, the results obtained from distance relay reset GIS Pesanggaran - GI Pemecutan Kelod, with impedance value 1 = 2.055 ?, zone 2 = 5.73 ? and zone 3 = 11.01 ? with time delay at zone 1 = 0 seconds, zone 2 = 0.4 seconds and zone 3 = 1.6 seconds. This setting shows that the reload setting value can secure the line from the 3 phase short circuit fault obtained from the simulation results.

Calculation of minimal short-circuit current in parallel arrangement of cables for a three phase short-circuit fault

Calculation of minimal short-circuit current in parallel arrangement of cables for a three phase short-circuit fault

A Permanent Magnet Assist, Segmented Rotor, Switched Reluctance Drive for Fault Tolerant Aerospace Applications

This paper presents the design, analysis, prototype, and testing of a new fault tolerant electrical drive topology. The segmented rotor switched reluctance machine (S-SRM) has been modified to include permanent magnet assist by placing magnets in the stator slot opening. This introduces a magnetic bias which extends the magnetic operating region of the machine and results in greater torque when compared to the conventional fault tolerant segmental rotor switched reluctance machine. This new torque dense, fault tolerant topology was investigated using 2-D (two-dimensional) and 3-DFE methods and a prototype machine built, tested and verified against the simulations. Experimental testing was carried out with and without the magnets to assess the effect of the PM assist on torque performance. Static tests were carried out to obtain the torque—flux linkage—angle waveforms and then this information used to tune a bespoke drive and test the system under dynamic conditions. The superior fault tolerant performance of this PMA S-SRM topology is highlighted by measurements taken under phase open and short circuit fault conditions. The tests show that this fault-tolerant topology not only meets the mass requirements of the aerospace application, set originally by a PMSM, but also, with the magnets now placed on the stator the rotational induced EMFs and associated short circuit currents during a fault are drastically reduced. Hence the fault tolerance of this topology is an improvement on the PMSM topology, and it will be of benefit to fault critical systems such as aerospace drives and actuators.

Symmetrical Loss of Excitation Fault Diagnosis in an Asynchronized High-Voltage Generator

As a new type of generator, an asynchronized high-voltage generator has the characteristics of an asynchronous generator and high voltage generator. The effect of the loss of an excitation fault for an asynchronized high-voltage generator and its fault diagnosis technique are still in the research stage. Firstly, a finite element model of the asynchronized high-voltage generator considering the field-circuit-movement coupling is established. Secondly, the three phase short-circuit loss of excitation fault, three phase open-circuit loss of excitation fault, and three phase short-circuit fault on the stator side are analyzed by the simulation method that is applied abroad at present. The fault phenomenon under the stator three phase short-circuit fault is similar to that under the three phase short-circuit loss of excitation. Then, a symmetrical loss of the excitation fault diagnosis system based on wavelet packet analysis and the Back Propagation neural network (BP neural network) is established. At last, we confirm that this system can eliminate the interference of the stator three phase short-circuit fault, accurately diagnose the symmetrical loss of the excitation fault, and judge the type of symmetrical loss of the excitation fault. It saves time to find the fault cause and improves the stability of system operation.

Simulation Analysis of Microgrid Voltage Stability with Multi-induction Motor Loads

This paper studies the voltage stability problem in microgrid with multi-induction motor (MIM) loads. Firstly, the dynamic coupling relationship between grid voltage and each motor load slip in microgrid with MIM loads is deduced based on the power balance theory of power system. Then, a multi-source and master slave control based microgrid model is built, where Matlab/Simulink software is used to analyze microgrid voltage stability under circumstances of MIMs superimposed starting and microgrid fault. Through simulation calculation and analysis, the measures to improve the voltage stability of microgrid with MIM loads are proposed. According to the simulation results, the interaction between MIM loads has great influence on microgrid voltage stability. In addition, the critical cleaning time (CCT) of series connected master slave control based microgrid is affected by the distance between three phase short circuit fault location and the induction motor load location, as well as the distance between fault location and main control unit. The microgrid voltage stability can be effectively improved by applying methods of superimposed starting strategy and fast motor cutting strategy. The conclusion provides a reference for voltage stability research and control of the microgrid with MIM loads.

Enhancing the LVRT Capability of PMSG-Based Wind Turbines Based on R-SFCL

A novel low voltage ride-through (LVRT) scheme for PMSG-based wind turbines based on the Resistor Superconducting Fault Current Limiter (R-SFCL) is proposed in this paper. The LVRT scheme is mainly formed by R-SFCL in series between the transformer and the Grid Side Converter (GSC), and basic modelling has been discussed in detail. The proposed LVRT scheme is implemented to interact with PMSG model in PSCAD/EMTDC under three phase short circuit fault condition, which proves that the proposed scheme based on R-SFCL can improve the transient performance and LVRT capability to consolidate grid connection with wind turbines.

Second Order Sliding Mode Control of Three Phase Four Switch VSI Fed Fault Reconfigurable Sensor Less PMSM Drive

Short circuit switch faults in PMSM drives results in improper response of drive and reconfiguration of such a faulty drive requires manual interruption. Hence an online fault reconfiguration scheme is required for continuous and stable operation of drives. Single phase short circuit fault identification and reconfiguration system for three phase four switch inverter fed sensor less PMSM drive is proposed. Fault Reconfiguration system involves an additional leg with two switches and TRIACs connected in each phase of inverter and also in additional leg. Fault is detected based on over current flow in any phase of motor due to short circuit faults. Fault reconfiguration system involves opening of TRIAC in a faulty phase and closing of TRIAC in additional leg. This method does not require any additional changes in hardware to identify fault and the time taken for fault identification and reconfiguration is short such that the over current is suppressed within its first cycle. In addition to fault reconfiguration scheme, a second order sliding mode controller for speed control of PMSM motor is proposed. This controller converges faster and has finite reaching time and settling time even if system has non linearity including system parameters variation with time. To validate the performance of proposed speed controller and fault reconfiguration scheme for three phase four switch inverter fed sensor less PMSM drive is simulated in MATLAB/Simulink environment.

A machine learning based optimized energy dispatching scheme for restoring a hybrid microgrid

A microgrid operated in stand alone mode is highly vulnerable to instability when the integration of intermittent energy sources are considered. If a short circuit fault occurs in a microgrid while operating at its design limit, often cost effective system recovery becomes a challenging task. Under such contingencies predictive analysis can be used to strengthen the system restoration schemes. In this study, a system based on machine learning algorithm is implemented to forecast the security of a standalone microgrid and based on the forecasting, schedule multiple backup diesel generators under the contingency of loss of a major generating unit. The underlying objective is to maintain the voltage stability with an optimized economic dispatch scheme, right after clearing a critical three phase short circuit fault. Finally, a promising set of outcomes are observed and discussed.

Grid connection to CPP in a deregulated electricity market: A case study related to fault current levels

Cost of power is one of the major driving factors for profit margins in any industry. Deregulation of electricity market enhances this opportunity for industry consumers to settle for minimum prices for the same usage of electricity. This leads to restructuring of existing power system networks. Addition of infinite power sources such as grid, demands for a thorough check of design limits of the available switchgear. Thus, short circuit current levels become a deciding factor in importing additional power with existing switchgear. In a Captive Power Plant (CPP), the maximum fault current levels are studied with respect to single phase to ground fault (Line to ground – LG) and three phase short circuit fault. Methods of grounding determine whether LG fault current can exceed the three phase fault current. This becomes necessary as the estimated maximum current is used for deciding the rated short circuit breaking capacity of switchgear. LG fault currents are computed and compared with three phase fault currents at different system voltage levels for a particular CPP where power import from grid is considered. An attempt is made to study the variation of Coefficient of grounding with system grounding resistance for a particular voltage level which is resistively grounded.

PMSG based wind system for real-time maximum power generation and low voltage ride through

This work presents an efficient control strategy for low voltage ride through (LVRT) and maximum power tracking of a permanent magnet synchronous generator (PMSG) based variable speed grid connected wind turbine generator. Three-level Neutral Point Clamped converters are connected back to back to perform the power conversion. A controller is proposed and implemented for the machine side converter to maximize the power generation and loss minimization under varying wind speed. A controller is also proposed and implemented for the grid side converter to transfer the generated power to a local load and grid by keeping the DC link voltage constant. To test the LVRT capability, a three phase short circuit fault is applied on the grid side. The real time digital simulator results on a 2 MW/4 kV PMSG verify the effectiveness and superiority of the proposed control scheme under different loading and fault conditions.

Fault Impact Analysis and Improvements for a Large-scale Offshore Wind Farm Connected to Grid by Long HVAC Cables

A large-scale offshore wind power system with a capacity 200MW will be erected in the Peng-Hu islands, located about 60 km off the west coast of Taiwan. The system will be connected to Taiwan’s main grid by long high-voltage alternating-current (HVAC) submarine cables. The system impact of three phase short circuit faults are analyzed based on PSS/E simulations of type-B, C and D turbines. The system framework, associated parameters, and the features of different types of wind turbines are described. Responses of voltages, frequencies and powers of each turbine type due to fault disturbance are analyzed. In addition, the voltage and frequency variations of the Taiwan and Peng-Hu grids are compared in terms of different turbine types. Finally, improvements based on static VAr compensator (SVC) and static synchronous compensator (STATCOM) technologies are presented and their fault impact mitigation capacities are analyzed. Analysis results show that fault impact is significantly dependent on turbine type and the presented compensators provide useful impact mitigation.

针对两相短路故障的时间窗自动提取算法设计

本文针对输电线路两相短路故障，提出了一种基于工频分量单端故障测距原理的时间窗提取算法。此算法利用故障电流的差值对时间窗进行定位。首先利用PSCAD/EMTDC仿真软件搭建输电线路分布参数模型，对输电线路发生两相短路故障进行仿真建模，然后将仿真结果导入MATLAB，最后利用所提时间窗自动提取算法对故障点进行定位。经过对测距结果的分析，本文所提时间窗自动提取算法在输电线路发生两相短路故障后能有效对时间窗进行提取，可以为微机保护装置时间窗的快速准确选取提供参考。 This paper proposes a new time window automatic extraction algorithm of two phase short circuit fault based on power frequency component of the single-ended ranging principle. The time window automatic extraction algorithm is based on the differences of the phase current of fault phase to locate the time window. First, the transmission line distributed parameter model is built by using PSCAD/EMTDC simulation software to simulate two-phase short circuit fault. Then, the results of the two-phase short circuit fault simulation are used to the input of MATLAB. Finally, the algorithm proposed in this paper is used to locate the fault point. The result of the fault location verifies that the algorithm is feasible. The algorithm proposed in this paper can effectively extract the time window of two phase short circuit fault which can provide reference to the microcomputer protection device.