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short-circuit-fault
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Reducing the Flow Rate of Short Circuit Fault Current at the Output of the High Voltage Power Supply
, M.Sc. Thesis Sharif University of Technology ; Kaboli, Shahriar (Supervisor)
Abstract
In this research, we have presented a method to delay the propagation of fault current in high voltage power supplies. Common protection methods usually protect the load and do not protect the power supply itself well. In this research, our goal was to propose a method to prevent the short circuit fault current from reaching the power supply elements. At first, the available methods to limit the fault current and protect the high voltage power sources were studied and investigated. Then, using the transmission line theory, a ladder filter was designed as an alternative to the normal filter at the output of the power supply. In the next step, using software simulation, the performance of the...
Stability Improvement and Protection of Grid-following Bidirectional Three-phase Voltage-sourced Converters under Unbalanced Grid Conditions
, M.Sc. Thesis Sharif University of Technology ; Mokhtari, Hossein (Supervisor) ; Karimi, Houshang (Co-Supervisor)
Abstract
With the increasing expansion of modern DC loads and utilizing energy storage systems along with distributed renewable energy resources, grid-following bidirectional voltage-sourced converters (GFBVSCs) with fast dynamic performance are required. Due to the presence of single-phase loads and asymmetrical short circuit faults, unbalanced grid voltage conditions are available in the distribution system. Under unbalanced conditions, an oscillating component with a frequency of twice the grid angular frequency appears on the DC side. Removing double-frequency ripple in the DC link voltage without third harmonic current injection and reactive power injection to the grid based on the grid codes to...
Improvement of Inverter-based AC Microgrids Protection Against Short Circuit
, Ph.D. Dissertation Sharif University of Technology ; Mokhtari, Hossein (Supervisor) ; Blaabjerg, Frede (Co-Supervisor)
Abstract
Inverter-based distributed generations (IBDGs) have gained special interest in the electricity supply chain due to the advancements in power electronics technology. Power electronic inverters provide high-efficiency energy conversion with full controllability over a wide operating range, and ancillary services such as reactive power support and active filtering. Considering the voltage and frequency control capability of power inverters, supplying inverter-based micro-grid (IBMG) loads is now pissible. Despite the significant opportunities associated with such sources, they introduce new challenges that should be addressed properly. Reliable and accurate protection against short circuit...
Voltage balancing of series IGBTs in short-circuit conditions
, Article IEEE Transactions on Power Electronics ; Volume 37, Issue 5 , 2022 , Pages 5675-5686 ; 08858993 (ISSN) ; Peyghami, S ; Iannuzzo, F ; Blaabjerg, F ; Kaboli, S ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2022
Abstract
This article proposes a scheme for balancing the voltage of series-connected insulated gate bipolar transistors (IGBTs), which is also very effective under short-circuit conditions. An optimized clamp-mode snubber is proposed, including an active-driver to balance the currents of the IGBTs during short-circuit, which in turn allows for a considerable reduction of the snubber capacitance. The approach is proven to be effective under short-circuit conditions by a maximum of 55 V voltage increment and a negligible difference in the current values. The effectiveness of the proposed approach is demonstrated through simulations in PSPICE software and experimental tests performed at 2 kV. ©...
Short-circuit analysis in three-phase quasi-Z-source inverter
, Article 17th IEEE International Conference on Environment and Electrical Engineering and 2017 1st IEEE Industrial and Commercial Power Systems Europe, EEEIC / I and CPS Europe 2017, 6 June 2017 through 9 June 2017 ; 2017 ; 9781538639160 (ISBN) ; Moghani, J. S ; Noroozi, N ; Zolghadri, M. R ; IEEE EMC Society; IEEE Industry Applications Society (IAS); IEEE Power and Energy Society (PES) ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2017
Abstract
In this paper, the short-circuit fault in three-phase quasi-Z-source inverter (q-ZSI) is analyzed and a linear model is proposed for the short-circuit analysis. The proposed model is based on the state space equations of the system. By using this model, the most critical situation during short-circuit fault is recognized; the maximum reaction time for the protection system could be estimated and elements that are prone to failure are identified as well. The analysis is categorized into two groups, leg fault and switch fault. The linear model is confirmed by simulation of 1kw three-phase q-ZSI. © 2017 IEEE
Reinforcing fault ride through capability of grid forming voltage source converters using an enhanced voltage control scheme
, Article IEEE Transactions on Power Delivery ; 2018 ; 08858977 (ISSN) ; Mokhtari, H ; Ghasemi, M. A ; Blaabjerg, F ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2018
Abstract
Medium power distributed energy resources (DERs) are commonly connected to medium voltage distribution systems via voltage source converters (VSCs). Several guidelines and standards have been developed to establish the needed criteria and requirements for DERs interconnections. In this respect, it is preferred to reinforce the VSC fault ride through (FRT) capability, which considerably minimizes the DG outage period and reconnection time and results in a resilient system against short circuits. Considering the significant number of asymmetrical faults in distribution systems, the VSC response in such conditions must be investigated, and consequently, its FRT capability must be reinforced. In...
Reinforcing fault ride through capability of grid forming voltage source converters using an enhanced voltage control scheme
, Article IEEE Transactions on Power Delivery ; Volume 34, Issue 5 , 2019 , Pages 1827-1842 ; 08858977 (ISSN) ; Mokhtari, H ; Ghasemi, M. A ; Blaabjerg, F ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
Medium power distributed energy resources (DERs) are commonly connected to medium voltage distribution systems via voltage source converters (VSCs). Several guidelines and standards have been developed to establish the needed criteria and requirements for DERs interconnections. In this respect, it is preferred to reinforce the VSC fault ride through (FRT) capability, which considerably minimizes the DG outage period and reconnection time and results in a resilient system against short circuits. Considering the significant number of asymmetrical faults in distribution systems, the VSC response in such conditions must be investigated, and consequently, its FRT capability must be reinforced. In...
Quick diagnosis of short circuit faults in cascaded H-bridge multilevel inverters using FPGA
, Article Journal of Power Electronics ; Volume 17, Issue 1 , 2017 , Pages 56-66 ; 15982092 (ISSN) ; Zolghadri, M. R ; Rodriguez, J ; Shahbazi, M ; Oraee, H ; Lezana, P ; Schmeisser, A. U ; Sharif University of Technology
Korean Institute of Power Electronics
2017
Abstract
Fast and accurate fault detection is the primary step and one of the most important tasks in fault tolerant converters. In this paper, a fast and simple method is proposed to detect and diagnosis the faulty cell in a cascaded H-bridge multilevel inverter under a short circuit fault. In this method, the reference voltage is calculated using switching control pulses and DC-Link voltages. The comparison result of the output voltage and the reference voltage is used in conjunction with active cell pulses to detect the faulty cell. To achieve this goal, the cell which is active when the Fault signal turns to “0” is detected as the faulty cell. Furthermore, consideration of generating the active...
Proposal of an analytical model for performance evaluation of WR -resolvers under short circuit fault
, Article 27th Iranian Conference on Electrical Engineering, ICEE 2019, 30 April 2019 through 2 May 2019 ; 2019 , Pages 486-490 ; 9781728115085 (ISBN) ; Nasiri Gheidari, Z ; Tootoonchian, F ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
Wound-Rotor (WR) resolvers are the most widely used position sensors in applications with harsh environmental conditions. However, their performance is exposed to failure due to high risk of short circuit (SC) fault. Although the output current of the resolver is negligible, its thin copper wires increases the probability of the short circuit fault. To avoid the propagation of the turn-to turn SC fault to the whole coil and undesirable performance of the motion control drive, it is necessary to diagnose it at the very beginning of its development. Meanwhile, the first step of diagnosing faults is their modeling. Time stepping finite element analysis is the most accurate, but computationally...
Improving the accuracy of wound-rotor resolvers under inter-turn short circuit faults
, Article IEEE Sensors Journal ; Volume 21, Issue 5 , November , 2020 , Pages: 5944 - 5951 ; Tootoonchian, F ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2020
Abstract
The performance of the resolver as a position sensor is significantly influenced by electrical and mechanical faults. Among different faults, short circuit in the stator windings has more destructive effect than others on accuracy of resolver. Furthermore, due to thin wires of the stator it is highly likely to occur. Therefore, in this paper a robust design is proposed for wound-rotor resolvers to not only suppress the influence of short circuit fault in the stator/rotor winding, but also improve the accuracy of the sensor under mechanical faults. The effectiveness of the proposed robust design is demonstrated by an analytical model based on winding function method and then approved by time...
Improving the accuracy of wound-rotor resolvers under inter-turn short circuit faults
, Article IEEE Sensors Journal ; Volume 21, Issue 5 , 2021 , Pages 5944-5951 ; 1530437X (ISSN) ; Tootoonchian, F ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2021
Abstract
The performance of the resolver as a position sensor is significantly influenced by electrical and mechanical faults. Among different faults, short circuit in the stator windings has more destructive effect than others on accuracy of resolver. Furthermore, due to thin wires of the stator it is highly likely to occur. Therefore, in this paper a robust design is proposed for wound-rotor resolvers to not only suppress the influence of short circuit fault in the stator/rotor winding, but also improve the accuracy of the sensor under mechanical faults. The effectiveness of the proposed robust design is demonstrated by an analytical model based on winding function method and then approved by time...
Fault analysis on AC railway supply system
, Article 6th Annual International Power Electronics, Drive Systems, and Technologies Conference, PEDSTC 2015, 3 February 2015 through 4 February 2015 ; February , 2015 , Pages 567-572 ; 9781479976539 (ISBN) ; Mokhtari, H ; Zolghadri, M. R ; Khodabandeh, M ; Abazai, A ; Seyyedi Khakshani, R ; Mazaheri, S ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2015
Abstract
A short circuit fault in an AC railway supply system could have undesired consequences; including high-amplitude current flow in the power path, the rail potential rise in the fault vicinity. This paper studies the problem of the rail voltage rise in Tehran-Karaj railway system by the use of a steady state circuit model for the AC autotransformer during a phase-to-ground fault. By using this model, all the currents and voltages of the system can be easily calculated for all possible short circuit fault locations. With the help of the derived analytical model, one can also predict the possible fault locations which may cause the protection system to operate. The estimation of the system...
Fast short circuit power switch fault detection in cascaded H-bridge multilevel converter
, Article IEEE Power and Energy Society General Meeting ; 2013 ; 19449925 (ISSN); 9781479913039 (ISBN) ; Zolghadri, M. R ; Poure, P ; Saadate, S ; Sharif University of Technology
2013
Abstract
Multilevel converters are being widely used in a large number of power electronics applications. Due to the increased number of switching devices, they are more likely to have faults in their switches than the conventional converters. In order to have a balanced operation after a short circuit power switch fault occurrence, it is necessary to detect the fault location. In this paper, a fast power switch fault detection method is presented to identify the fault location. This method only needs one additional voltage sensor per phase, and is faster compared to most of the existing methods. Also it is easy for implementation on a FPGA chip. The proposed method is verified by computer...
Fast fault detection method for modular multilevel converter semiconductor power switches
, Article IET Power Electronics ; Volume 9, Issue 2 , 2016 , Pages 165-174 ; 17554535 (ISSN) ; Khodabandeh, M ; Zolghadri, M. R ; Sharif University of Technology
Institution of Engineering and Technology
2016
Abstract
This study proposes a new fault detection method for modular multilevel converter (MMC) semiconductor power switches. While in common MMCs, the cells capacitor voltages are measured directly for control purposes, in this study voltage measurement point changes to the cell output terminal improving fault diagnosis ability. Based on this measurement reconfiguration, a novel fault detection algorithm is designed for MMCs semiconductor power switches. The open circuit and short circuit faults are detected based on unconformity between modules output voltage and switching signals. Simulation and experimental results confirm accurate and fast operation of the proposed method in faulty cell...
Detecting the location of short-circuit faults in active distribution network using pmu-based state estimation
, Article IEEE Transactions on Smart Grid ; Volume 11, Issue 2 , 2020 , Pages 1396-1406 ; Abbaspour, A ; Moeini Aghtaie, M ; Fotuhi Firuzabad, M ; Lehtonen, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2020
Abstract
With the rapid advancement of phasor measurement units (PMUs) technology, system operators in different level of power systems have access to new and abundant measurements. Taking into account these measurements in active distribution systems (ADNs), a new algorithm for short-circuit fault detection and identification based on state estimation (SE) is introduced in this paper. In this regard, as the first step, traditional SE process is revised to be compatible with fault conditions. Then, a fault location algorithm (FLA) based on the revised SE (RDSSE) is presented which attends to detect the location of fault after diagnosing faulted zone. For this purpose, current and voltage...
Control of grid-following inverters under unbalanced grid conditions
, Article IEEE Transactions on Energy Conversion ; Volume 35, Issue 1 , 2020 , Pages 184-192 ; Mokhtari, H ; Ghasemi, M. A ; Peyghami, S ; Davari, P ; Blaabjerg, F ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2020
Abstract
This paper proposes a new control scheme to eliminate the 3rd harmonic in the output currents of grid-following inverters under unbalanced grid conditions. Unbalanced grids adversely affect the performance of grid-following inverters due to the oscillations appearing on the DC-link voltage with a frequency twice the line frequency. The paper is based on instantaneous active reactive control (IARC) technique due to its advantages over other existing methods. However, the presence of severe asymmetrical 3rd harmonic distortions in the inverter output currents is the main challenge with IARC method, which impairs the power quality requirements. This paper enhances the IARC scheme by proposing a...
Comprehensive analytics for reliability evaluation of conventional isolated multiswitch PWM DC-DC converters
, Article IEEE Transactions on Power Electronics ; Volume 35, Issue 5 , 2020 , Pages 5254-5266 ; Panahandeh Esmaeelnia, F ; Fotuhi Firuzabad, M ; Tahami, F ; Tohidi, S ; Dehghanian, P ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2020
Abstract
This article offers a holistic model and approach on reliability assessment of conventional isolated multiswitch pulsewidth modulation dc-dc (IMSDC-DC) power electronic converters with conventional half-bridge, full-bridge, and push-pull dc-dc topologies. The proposed reliability assessment analytics encapsulate correlated effects of several conditions (e.g., open- and short-circuit faults) and prevailing parameters (e.g., duty cycle, input voltage, output power, transformer turns ratio, voltage gain, switching frequency, operation time duration, and components characteristics) on the overall reliability performance of IMSDC-DC converters. Such insights are then harnessed within a Markov...
A voltage balancing method for series-connected igbts operating as a fault current limiter in high-voltage dc power supplies
, Article IEEE Transactions on Industrial Electronics ; Volume 68, Issue 9 , 2021 , Pages 7895-7907 ; 02780046 (ISSN) ; Zarghani, M ; Kaboli, S ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2021
Abstract
This article proposes a high-voltage fault current limiter (HVFCL) for high-voltage dc power supplies (HVdcPSs) which limits the current of the power supply automatically in the short-circuit fault (SCF). The proposed HVFCL is based on the series-connected insulated gate bipolar transistors (IGBTs). The main achievements of this article are the balanced voltage sharing and a very low value of the short-circuit current near to the load nominal current for the series-connected IGBTs during the SCF. These achievements result in a longer maximum permissible short-circuit time. These achievements are obtained by a control strategy that puts the series-connected IGBTs in a specific operating point...
A short-circuit fault diagnosis method for three-phase quasi-Z-source inverters
, Article IEEE Transactions on Industrial Electronics ; Volume 68, Issue 1 , 2021 , Pages 672-682 ; 02780046 (ISSN) ; Yaghoubi, M ; Zolghadri, M. R ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2021
Abstract
In this article, we present a cost-effective solution for switching short-circuit fault diagnosis in a three-phase quasi-Z-source inverter (qZSI). The fault is announced to the processor utilizing a peripheral circuit that covers the fault detection in all switches of the inverter. After the fault detection, a nonmaskable interrupt is activated, cutting the CPU routine, and a fault-diagnosis algorithm is initiated. The exact location of the failed switch is identified through the proposed algorithm. The entire process is accomplished in advance of the critical overcurrent condition, which typically arises after a short-circuit fault. Thanks to this overtake, the proposed technique prevents...
A series stacked IGBT switch to be used as a fault current limiter in HV high-power supplies
, Article IEEE Journal of Emerging and Selected Topics in Power Electronics ; Volume 9, Issue 5 , 2021 , Pages 6300-6314 ; 21686777 (ISSN) ; Zarghani, M ; Kaboli, S ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2021
Abstract
The safe operating condition for the vacuum tubes is very important and critical since they are very expensive and delicate. Providing limited short circuit energy for the vacuum tube and fast transferring from the short circuit to the nominal operation state are absolutely necessary. Extant protection strategies threat the availability of the vacuum tubes. In addition, they cannot completely protect the tube due to the delay of the fault detection system. This article proposes a high voltage (HV) short circuit fault current limiter which can limit the short circuit energy of the system inherently. The proposed structure activates automatically when the current exceeds the predetermined...