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This paper proposes an equivalent circuit model to obtain the transient electrical stress quantitatively in medium voltage medium frequency transformers in modern power electronics. To verify this model, transient simulation is performed on a 1.5 kV/1 kHz transformer, revealing voltage overshoot quantitatively between turns and layers of the transformer’s HV winding. Effects of rise time of the input pulse voltage, stray capacitance of the winding insulation, and their interactions on the voltage overshot magnitude are presented. With these results, we propose limiting the voltage overshoot and, thereafter, enhancing medium voltage medium frequency transformer’s insulation capability, which throws light on the transformer’s insulation design. Additionally, guidance on the future studies on aging and endurance lifetime of the medium voltage medium frequency transformer’s insulation could be given.
Zheng Changjiang; Wang Qian; Wang Huai; Shen Zhan; Claus Leth Bak. Electrical Stress on the Medium Voltage Medium Frequency Transformer. Energies 2021, 14, 5136 .
AMA StyleZheng Changjiang, Wang Qian, Wang Huai, Shen Zhan, Claus Leth Bak. Electrical Stress on the Medium Voltage Medium Frequency Transformer. Energies. 2021; 14 (16):5136.
Chicago/Turabian StyleZheng Changjiang; Wang Qian; Wang Huai; Shen Zhan; Claus Leth Bak. 2021. "Electrical Stress on the Medium Voltage Medium Frequency Transformer." Energies 14, no. 16: 5136.
In this paper, a methodology for optimal decision making for electrical systems is addressed. This methodology seeks to identify and to prioritize the replacement and maintenance of a power asset fleet optimizing the return of investment. It fulfills this objective by considering the risk index, the replacement and maintenance costs, and the company revenue. The risk index is estimated and predicted for each asset using both its condition records and by evaluating the consequence of its failure. The condition is quantified as the probability of failure of the asset, and the consequence is determined by the impact of the asset failure on the whole system. Failure probability is estimated using the health index as scoring of asset condition. The consequence is evaluated considering a failure impact on the objectives of reliability (energy not supplied -ENS), environment, legality, and finance using Monte Carlo simulations for an assumed period of planning. Finally, the methodology was implemented in an open-source library called PywerAPM for assessing optimal decisions, where the proposed mathematical optimization problem is solved. As a benchmark, the power transformer fleet of the New England IEEE 39 Bus System was used. Condition records were provided by a local utility to compute the health index of each transformer. Subsequently, a Monte Carlo contingency simulation was performed to estimate the energy not supplied for a period of analysis of 10 years. As a result, the fleet is ranked according to risk index, and the optimal replacement and maintenance are estimated for the entire fleet.
David L. Alvarez; Diego F. Rodriguez; Alben Cardenas; F. Faria da Silva; Claus Leth Bak; Rodolfo García; Sergio Rivera. Optimal Decision Making in Electrical Systems Using an Asset Risk Management Framework. Energies 2021, 14, 4987 .
AMA StyleDavid L. Alvarez, Diego F. Rodriguez, Alben Cardenas, F. Faria da Silva, Claus Leth Bak, Rodolfo García, Sergio Rivera. Optimal Decision Making in Electrical Systems Using an Asset Risk Management Framework. Energies. 2021; 14 (16):4987.
Chicago/Turabian StyleDavid L. Alvarez; Diego F. Rodriguez; Alben Cardenas; F. Faria da Silva; Claus Leth Bak; Rodolfo García; Sergio Rivera. 2021. "Optimal Decision Making in Electrical Systems Using an Asset Risk Management Framework." Energies 14, no. 16: 4987.
This paper studies optimal shunt busbar capacitor placement for large-scale VSC-MTDC grids to accurately discriminate between faults inside each protection zone and external faults. The installed capacitors work as filters, which attenuate higher frequencies for faults outside the zone and keep internal fault transients unchanged. The objective function is a trade-off between total installation and maintenance cost and the discrimination sufficiency, while constraints related to the grid operation must be satisfied. Discrete wavelet transform (DWT) is used to calculate wavelet energies and to define relay detection criteria. The proposed method is applied to CIGRE large-scale VSC-MTDC grid in PSCAD/EMTDC. MATLAB is used for DWT-based signal processing with Python used as an interface between PSCAD and MATLAB for optimization based on the Watercycle optimization algorithm (WCA). Multiple faults with different characteristics are simulated to test the optimal results in different situations. The optimal results show that the proposed principle accurately discriminates between internal and external faults. Simulation results prove accurate detection of the faulty section using both two-sided measurement and one-sided measurement with half of measuring and protection equipment. The sensitivity of the method to faults close to the measuring points and the impact of different DWT levels is analysed.
Mani Ashouri; Filipe Faria da Silva; Claus Leth Bak. Optimal Shunt Busbar Capacitor Placement for Selective Protection of Large-Scale VSC-MTDC Grids. Electric Power Systems Research 2021, 199, 107458 .
AMA StyleMani Ashouri, Filipe Faria da Silva, Claus Leth Bak. Optimal Shunt Busbar Capacitor Placement for Selective Protection of Large-Scale VSC-MTDC Grids. Electric Power Systems Research. 2021; 199 ():107458.
Chicago/Turabian StyleMani Ashouri; Filipe Faria da Silva; Claus Leth Bak. 2021. "Optimal Shunt Busbar Capacitor Placement for Selective Protection of Large-Scale VSC-MTDC Grids." Electric Power Systems Research 199, no. : 107458.
In this paper, a full-wave approach based on the method of moment (MoM) is proposed to investigate the harmonic impedance of a tower and its connected ground electrode in the frequency domain. The accuracy of the results is validated in comparison with NEC-4. The proposed numerical method is also employed for the evaluation of a full-sized HVDC tower harmonic impedance. The main contribution is the assessment of the harmonic impedance of a real tower with detailed geometrical information connected to the multi-layer grounding system. The validity of the transmission line method is evaluated through comparison with the results computed using the developed full-wave approach at the high frequency. In addition, the simulation results assure that a real tower’s harmonic impedance could be smaller than the value estimated for very simplified models at the high frequencies. When the full-wave method is applied and the precise model of the ground electrode is considered, the harmonic impedance of the tower in the frequency domain and consequently, the transient impedance in the time domain are different, while the grounding system is assumed to be a perfectly conducting plane. These differences can become very significant, especially close to the resonant frequencies. The harmonic impedance of power transmission towers is strongly influenced by the connected grounding system.
M. Ghomi; H. Zhang; C. Leth Bak; F. Faria da Silva; K. Yin. Integrated model of transmission tower surge impedance and multilayer grounding system based on full-wave approach. Electric Power Systems Research 2021, 198, 107355 .
AMA StyleM. Ghomi, H. Zhang, C. Leth Bak, F. Faria da Silva, K. Yin. Integrated model of transmission tower surge impedance and multilayer grounding system based on full-wave approach. Electric Power Systems Research. 2021; 198 ():107355.
Chicago/Turabian StyleM. Ghomi; H. Zhang; C. Leth Bak; F. Faria da Silva; K. Yin. 2021. "Integrated model of transmission tower surge impedance and multilayer grounding system based on full-wave approach." Electric Power Systems Research 198, no. : 107355.
A design of a fully composite pylon with external grounding down-leads has been proposed for new-generation 400 kV transmission towers, able to save lines corridors and to reduce visual impact. This paper investigates and compares the backflashover performance of a composite pylon and two conventional metallic towers, which have been widely installed in Denmark. The transient models of overhead lines and all three towers were established respectively and the transient analysis was carried out in PSCAD. Monte Carlo method was used to estimate backflashover rate. The backflashover rate of composite pylon is 0.4526 cases per 100 km per year, which is in the same range, but slightly higher than that of metallic towers. The separated grounding down-leads of double circuits on composite pylon eliminates the danger of simultaneous backflashover of double circuits, which exists in transmission lines supported by metallic towers. After comparing the overvoltages to three phases of the three towers from backflashover, it is worthy considering that the installation of surge arresters at all three phases of composite pylon has a strong impact on the backflashover rather, but for the two metallic towers only the surge arresters at the upper phase has an impact.
H. Zhang; M. Ghomi; Q. Wang; F.Faria da Silva; C.L. Bak; K. Yin; H. Skouboe. Comparison of Backflashover performance between a novel composite pylon and metallic towers. Electric Power Systems Research 2021, 196, 107263 .
AMA StyleH. Zhang, M. Ghomi, Q. Wang, F.Faria da Silva, C.L. Bak, K. Yin, H. Skouboe. Comparison of Backflashover performance between a novel composite pylon and metallic towers. Electric Power Systems Research. 2021; 196 ():107263.
Chicago/Turabian StyleH. Zhang; M. Ghomi; Q. Wang; F.Faria da Silva; C.L. Bak; K. Yin; H. Skouboe. 2021. "Comparison of Backflashover performance between a novel composite pylon and metallic towers." Electric Power Systems Research 196, no. : 107263.
The controlled fault characteristics of power electronic-based power plant during unbalanced grid faults can heavily affect the proper operation of distance relay. In order to solve this issue, a fault control scheme is developed for the power electronic-based power plant, which is compliant with grid protection during unbalanced grid faults. Firstly, we analyze the essential problem of the distance relay on the transmission line connecting the power electronic-based power plant. Subsequently, we build the equivalent fault models of power electronic-based power plant in the sequence systems based on the reactive power supporting requirements defined in the modern fault-ride-through rules and the protection demands. From the analytic equation of apparent impedance in different fault loops, a novel protection collaborative fault control scheme to determine the proper current command angle of the power electronic-based power plant during unbalanced grid faults is deduced. Simulation results prove that the proposed fault control of power electronic-based power plant can improve the accuracy of reactance measurements in distance relay, which in turn reduces the malfunction risk of the relay.
Kaiqi Ma; Zhe Chen; Zhou Liu; Claus Leth Bak; Manuel Castillo. Protection collaborative fault control for power electronic-based power plants during unbalanced grid faults. International Journal of Electrical Power & Energy Systems 2021, 130, 107009 .
AMA StyleKaiqi Ma, Zhe Chen, Zhou Liu, Claus Leth Bak, Manuel Castillo. Protection collaborative fault control for power electronic-based power plants during unbalanced grid faults. International Journal of Electrical Power & Energy Systems. 2021; 130 ():107009.
Chicago/Turabian StyleKaiqi Ma; Zhe Chen; Zhou Liu; Claus Leth Bak; Manuel Castillo. 2021. "Protection collaborative fault control for power electronic-based power plants during unbalanced grid faults." International Journal of Electrical Power & Energy Systems 130, no. : 107009.
SEV, the Faroese Power Company, has a vision to reach a 100% renewable power system by 2030. SEV is committed to achieve this, starting from a 41% share of renewables in 2019. A detailed expansion plan for the generation, storage and transmission is needed to reach this goal. This is the focus of this study. Practical constrains e.g. resource potential and available space must be considered. Balmorel, an optimisation tool, has been used to optimise investments and dispatch. A method to translate optimal results to a realistic RoadMap was developed and applied. The impact of different technologies and costs has been investigated through multiple scenarios. In ratios of average consumption in 2030, installed power will be 224% wind, 105% solar with 8-9 days of pumped hydro storage according to the proposed RoadMap. The plan is economically favorable up to 87% of renewables, but in order to reach a 100% renewable production in an average weather year, the renewable generation capacity has to be increased by 80%. The study also shows that if biofules or tidal technologies become viable, these will be game changers needing a significantly lower total sum of installed renewable power.
Helma Maria Trondheim; Bárður A. Niclasen; Terji Nielsen; Filipe Faria Da Silva; Claus Leth Bak. 100% Sustainable Electricity in the Faroe Islands: Expansion Planning Through Economic Optimization. IEEE Open Access Journal of Power and Energy 2021, 8, 23 -34.
AMA StyleHelma Maria Trondheim, Bárður A. Niclasen, Terji Nielsen, Filipe Faria Da Silva, Claus Leth Bak. 100% Sustainable Electricity in the Faroe Islands: Expansion Planning Through Economic Optimization. IEEE Open Access Journal of Power and Energy. 2021; 8 (99):23-34.
Chicago/Turabian StyleHelma Maria Trondheim; Bárður A. Niclasen; Terji Nielsen; Filipe Faria Da Silva; Claus Leth Bak. 2021. "100% Sustainable Electricity in the Faroe Islands: Expansion Planning Through Economic Optimization." IEEE Open Access Journal of Power and Energy 8, no. 99: 23-34.
Fast and accurate fault detection and localization are important topics in voltage source converter-based high-voltage direct current transmission (VSC-HVDC) grids in order to isolate the fault after the first milliseconds of occurrence. Common signal processing methods used for detecting fault traveling wave (TW) peaks like Fourier transform, S-transform and wavelet-based techniques transform the signal into the frequency domain, requiring complicated computations. In this paper, the application of mathematical morphology (MM)-based filters for detecting and locating faults in VSC-HVDC links is studied. MM-based methods analyze the signal in the time domain and detect the wave peaks accurately. Multiple MM-based filters resulted from basic MM operators are presented and used for TW-based fault study in VSC-HVDC grids. Several fault cases are applied to the CIGRE VSC-HVDC model in PSCAD, and the MM-based scripts are written in MATLAB. The impact of different sizes and types of the structuring elements on the accuracy of peak detection is analyzed. The results show the accuracy of MM filters for detecting and locating fault transient in VSC-HVDC links. The proposed method gives accurate results for both low-impedance and high-impedance faults.
Mani Ashouri; Filipe Faria da Silva; Claus Leth Bak. Analysis and validation of mathematical morphology filters for single-ended fault localization in VSC-HVDC links. Electrical Engineering 2021, 103, 1583 -1596.
AMA StyleMani Ashouri, Filipe Faria da Silva, Claus Leth Bak. Analysis and validation of mathematical morphology filters for single-ended fault localization in VSC-HVDC links. Electrical Engineering. 2021; 103 (3):1583-1596.
Chicago/Turabian StyleMani Ashouri; Filipe Faria da Silva; Claus Leth Bak. 2021. "Analysis and validation of mathematical morphology filters for single-ended fault localization in VSC-HVDC links." Electrical Engineering 103, no. 3: 1583-1596.
The impacts of the static synchronous compensator (STATCOM) on the traditional loss of excitation (LOE) protection are investigated in this study. To do a comprehensive study, a common and realistic excitation system is developed for the generator by employing the phase-domain model of the synchronous generator accessible in the real-time-digital-simulator. Using such a model, LOE phenomenon is realistically studied in accordance with IEEE Standard C37. 102-2016, while the generator dynamics along with the LOE relay performance are investigated through different types of partial and complete LOE events. It is shown that in the presence of STATCOM, two major impacts on the generator and its LOE protection can be expected: i) It imposes an additional time delay on the relay to detect the LOE failures, which depends on the generator initial loading and the type of LOE failure, and ii) It might lead the generator to reach a new stable operating point without experiencing a loss of synchronism condition, during an improper changeover from AVR to MVR operating mode. The related consequences for both of the impacts are discussed in this paper and some solutions are suggested to deal with the probable negative aspects.
Abbas Hasani; Farhad Haghjoo; Claus Leth Bak; Filipe Faria da Silva. STATCOM Impacts on Synchronous Generator LOE Protection: A Realistic Study Based on IEEE Standard C37. 102. IEEE Transactions on Industry Applications 2020, 57, 1255 -1264.
AMA StyleAbbas Hasani, Farhad Haghjoo, Claus Leth Bak, Filipe Faria da Silva. STATCOM Impacts on Synchronous Generator LOE Protection: A Realistic Study Based on IEEE Standard C37. 102. IEEE Transactions on Industry Applications. 2020; 57 (2):1255-1264.
Chicago/Turabian StyleAbbas Hasani; Farhad Haghjoo; Claus Leth Bak; Filipe Faria da Silva. 2020. "STATCOM Impacts on Synchronous Generator LOE Protection: A Realistic Study Based on IEEE Standard C37. 102." IEEE Transactions on Industry Applications 57, no. 2: 1255-1264.
A review of the ongoing research on black start (BS) service integrated with offshore wind farms (OWFs) is presented in this paper. The overall goal is to firstly gain a better understanding of the BS capabilities required by modern power systems. Subsequently, the challenges faced by OWFs as novel BS service providers as well as an outlook on the ongoing research which may provide solutions to these are presented. OWFs have the potential to be a fast and environmentally friendly technology to provide BS services for power system restoration and, therefore, to ensure resiliency after blackouts. As a power electronic-based system, OWFs can be equipped with a self-starter in the system in order to perform BS. The self-start unit could be a synchronous generator (SG) or a power electronic unit such as a grid-forming (GFM) converter. Preliminary BS studies performed in PSCAD/EMTDC are presented in a simplified OWF system via an SG as the self-start unit. Consequently, technical challenges during the BS procedure in an OWF benchmark system are outlined via theoretical discussions and simulations results. This is useful to understand the threats to power electronics during BS. Finally, the most relevant GFM strategies in the state-of-the-art literature are presented and their application to OWF BS is discussed.
Daniela Pagnani; Frede Blaabjerg; Claus Leth Bak; Filipe Miguel Faria Da Silva; Łukasz H. Kocewiak; Jesper Hjerrild. Offshore Wind Farm Black Start Service Integration: Review and Outlook of Ongoing Research. Energies 2020, 13, 6286 .
AMA StyleDaniela Pagnani, Frede Blaabjerg, Claus Leth Bak, Filipe Miguel Faria Da Silva, Łukasz H. Kocewiak, Jesper Hjerrild. Offshore Wind Farm Black Start Service Integration: Review and Outlook of Ongoing Research. Energies. 2020; 13 (23):6286.
Chicago/Turabian StyleDaniela Pagnani; Frede Blaabjerg; Claus Leth Bak; Filipe Miguel Faria Da Silva; Łukasz H. Kocewiak; Jesper Hjerrild. 2020. "Offshore Wind Farm Black Start Service Integration: Review and Outlook of Ongoing Research." Energies 13, no. 23: 6286.
Loss of excitation (LOE) relay is one of the most essential protection elements for synchronous generators in power plants. During the last few decades, several LOE detection methods have been proposed, while limited schemes such as admittance- and impedance-based ones have been adopted for industrial applications. This study investigates and compares the behavior of some practical LOE detection schemes through extensive simulation scenarios, and from the reliability, speed, and security points of view. The simulation scenarios are accomplished by using the real-time-digital-simulator, where the phase domain model of the synchronous generator is used to develop a realistic and typical power generation system. Employing such a system, different types of complete and partial LOE incidents can be applied according to IEEE Standard C37.102-2006, while the performance of any scheme can be assessed through accurate and realistic LOE scenarios.
Abbas Hasani; Claus Bak; Filipe Silva. Performance Assessment of Some Practical Loss of Excitation Detection Schemes Employing a Realistic Model. Energies 2020, 13, 5928 .
AMA StyleAbbas Hasani, Claus Bak, Filipe Silva. Performance Assessment of Some Practical Loss of Excitation Detection Schemes Employing a Realistic Model. Energies. 2020; 13 (22):5928.
Chicago/Turabian StyleAbbas Hasani; Claus Bak; Filipe Silva. 2020. "Performance Assessment of Some Practical Loss of Excitation Detection Schemes Employing a Realistic Model." Energies 13, no. 22: 5928.
This study proposes a modal online differential fault detection and localization (MODF) scheme for VSC-MTDC cable transmission. Modal theory is used to remove the coupling between layers of two-core extruded high-voltage direct current cable. As a result, the decoupled modes are determined and the modal matrix resulted. In high frequencies, the modes have different velocities, which result in a time difference between modal initial peaks. This time delay is used to design modal fault detection and localization scheme, which can work in a variety of strategies like pilot or non-communicated protection systems, one-sided or two-sided relaying, and single-zone or double-zone relay settings. Novel modal time–distance characteristics are introduced for adjusting the zone setting of relays in the MODF scheme. Multiple faults are applied to the CIGRE VSC-MTDC model in the real-time digital simulator with a Beckhoff CX5130 controller in the hardware-in-the-loop setup for testing the proposed MODF scheme. The advantages and weak points of each strategy are analyzed and compared for the modelled faults. Hilbert–Huang transform is used for the accurate detection of modal initial peaks. It is shown that the method gives accurate and selective results for a wide range of VSC-MTDC configurations.
Mani Ashouri; Filipe Faria da Silva; Claus Leth Bak; Aliakbar Abdoos; Seyed Mehdi Hosseini. Modal online differential fault detection and localisation scheme for VSC‐MTDC cable transmission. IET Generation, Transmission & Distribution 2020, 14, 4475 -4487.
AMA StyleMani Ashouri, Filipe Faria da Silva, Claus Leth Bak, Aliakbar Abdoos, Seyed Mehdi Hosseini. Modal online differential fault detection and localisation scheme for VSC‐MTDC cable transmission. IET Generation, Transmission & Distribution. 2020; 14 (20):4475-4487.
Chicago/Turabian StyleMani Ashouri; Filipe Faria da Silva; Claus Leth Bak; Aliakbar Abdoos; Seyed Mehdi Hosseini. 2020. "Modal online differential fault detection and localisation scheme for VSC‐MTDC cable transmission." IET Generation, Transmission & Distribution 14, no. 20: 4475-4487.
By the increase of the penetration of power-electronic-based (PE-based) units, such as wind turbines and PV systems, many features of those power systems, such as stability, security, and protection, have been changed. In this paper, the security of electrical grids with high wind turbines penetration is discussed. To do so, first, an overview of the power systems’ security assessment is presented. Based on that, stability and security challenges introduced by increasing the penetration of wind turbines in power systems are studied, and a new guideline for the security assessment of the PE-based power systems is proposed. Simulation results for the IEEE 39-bus test system show that the proposed security guideline is necessary for PE-based power systems, as the conventional security assessments may not be able to indicate its security status properly.
Bahram Shakerighadi; Saeed Peyghami; Esmaeil Ebrahimzadeh; Frede Blaabjerg; Claus Leth Back. A New Guideline for Security Assessment of Power Systems with a High Penetration of Wind Turbines. Applied Sciences 2020, 10, 3190 .
AMA StyleBahram Shakerighadi, Saeed Peyghami, Esmaeil Ebrahimzadeh, Frede Blaabjerg, Claus Leth Back. A New Guideline for Security Assessment of Power Systems with a High Penetration of Wind Turbines. Applied Sciences. 2020; 10 (9):3190.
Chicago/Turabian StyleBahram Shakerighadi; Saeed Peyghami; Esmaeil Ebrahimzadeh; Frede Blaabjerg; Claus Leth Back. 2020. "A New Guideline for Security Assessment of Power Systems with a High Penetration of Wind Turbines." Applied Sciences 10, no. 9: 3190.
Bahram Shakerighadi; Esmaeil Ebrahimzadeh; Mads Graungaard Taul; Frede Blaabjerg; Claus Leth Bak. Modeling and Adaptive Design of the SRF-PLL: Nonlinear Time-Varying Framework. IEEE Access 2020, 8, 28635 -28645.
AMA StyleBahram Shakerighadi, Esmaeil Ebrahimzadeh, Mads Graungaard Taul, Frede Blaabjerg, Claus Leth Bak. Modeling and Adaptive Design of the SRF-PLL: Nonlinear Time-Varying Framework. IEEE Access. 2020; 8 ():28635-28645.
Chicago/Turabian StyleBahram Shakerighadi; Esmaeil Ebrahimzadeh; Mads Graungaard Taul; Frede Blaabjerg; Claus Leth Bak. 2020. "Modeling and Adaptive Design of the SRF-PLL: Nonlinear Time-Varying Framework." IEEE Access 8, no. : 28635-28645.
This paper presents the modal analysis of different HVDC cable bundles. Using modal theory, specific transformation matrices are presented, and the modal equivalent circuits are illustrated. The behavior of the resulting modes is studied in a wide frequency range, the impact of different cable parameters and burial configurations on the modal characteristics are analyzed. A concept for online fault localization in HVDC cable transmission based on the difference between the modal velocities and consequently the arrival times of the modal traveling wave (TW) initial peaks is presented. In this method, modal voltages and currents are used instead of direct measurements and the proposed concept uses one-sided measurement without needing to detect the second TW reflections. Multiple faults are applied to CIGRE HVDC models in PSCAD/EMTDC and the modal analysis is obtained in MATLAB. The impact of different sampling frequencies, fault resistance, fault location and different grounding schemes on the proposed modal fault location principle is analyzed. The theoretical results show the accuracy of the proposed modal fault localization concept for different HVDC cable bundles.
Mani Ashouri; Filipe Faria Da Silva; Claus Leth Bak. On the Application of Modal Transient Analysis for Online Fault Localization in HVDC Cable Bundles. IEEE Transactions on Power Delivery 2019, 35, 1365 -1378.
AMA StyleMani Ashouri, Filipe Faria Da Silva, Claus Leth Bak. On the Application of Modal Transient Analysis for Online Fault Localization in HVDC Cable Bundles. IEEE Transactions on Power Delivery. 2019; 35 (3):1365-1378.
Chicago/Turabian StyleMani Ashouri; Filipe Faria Da Silva; Claus Leth Bak. 2019. "On the Application of Modal Transient Analysis for Online Fault Localization in HVDC Cable Bundles." IEEE Transactions on Power Delivery 35, no. 3: 1365-1378.
Photovoltaic distributed generation (PVDG) has seen tremendous growth in recent years, especially in the residential sector. Among other concerns, the voltage rise in AC networks is considered the most limiting factor in achieving increased PV penetration levels. A steady-state impact study is performed on a CIGRE low-voltage (LV) residential network. This paper compares six techniques to increase the PV penetration limit in the LV residential network, namely single-phase penetration (SPP), Distribution Scheme 1 (DS1), Distribution Scheme 2 (DS2), alternate phase penetration (APP), offline tap adjustment (OTA) and switched on-load tap adjustment (SOLTA). PSCAD software is used for this study. The best results are obtained for the DS2-SOLTA case that gives the minimum voltage magnitude and voltage unbalance in the system. The steady-state results are validated by a dynamic data study using measured solar irradiance and residential load data. A novel approach is also proposed for calculating the worst day from the data set. The obtained results verify the effectiveness of the proposed approach.
Musharraf Wajahat; Hassan Abdullah Khalid; Ghullam Mustafa Bhutto; Claus Leth Bak. A Comparative Study into Enhancing the PV Penetration Limit of a LV CIGRE Residential Network with Distributed Grid-Tied Single-Phase PV Systems. Energies 2019, 12, 2964 .
AMA StyleMusharraf Wajahat, Hassan Abdullah Khalid, Ghullam Mustafa Bhutto, Claus Leth Bak. A Comparative Study into Enhancing the PV Penetration Limit of a LV CIGRE Residential Network with Distributed Grid-Tied Single-Phase PV Systems. Energies. 2019; 12 (15):2964.
Chicago/Turabian StyleMusharraf Wajahat; Hassan Abdullah Khalid; Ghullam Mustafa Bhutto; Claus Leth Bak. 2019. "A Comparative Study into Enhancing the PV Penetration Limit of a LV CIGRE Residential Network with Distributed Grid-Tied Single-Phase PV Systems." Energies 12, no. 15: 2964.
A new approach for generator loss of field (LOF) protection is proposed by estimating the field current based on the generator measurable parameters. The main idea of the proposed approach is that a significant difference will be created between the measured excitation and the estimated field currents during LOF occurrence. A differential index is introduced to monitor such difference and consequently to detect LOF failures. A detailed and realistic field circuit is considered for the generator by using the phase-domain model of the generator in the real-time digital simulator, while different types of LOF events can be simulated through such model as well. The obtained results show that the presented technique can detect various types of LOF events much faster than the conventional impedance-based scheme. Moreover, it exhibits more security than the conventional technique in the face of power system disturbances (e.g., stable power swing and out-of-step conditions).
Abbas Hasani; Farhad Haghjoo; Filipe Miguel Faria da Silva; Claus Leth Bak. A Current-Based Differential Technique to Detect Loss of Field in Synchronous Generators. IEEE Transactions on Power Delivery 2019, 35, 514 -522.
AMA StyleAbbas Hasani, Farhad Haghjoo, Filipe Miguel Faria da Silva, Claus Leth Bak. A Current-Based Differential Technique to Detect Loss of Field in Synchronous Generators. IEEE Transactions on Power Delivery. 2019; 35 (2):514-522.
Chicago/Turabian StyleAbbas Hasani; Farhad Haghjoo; Filipe Miguel Faria da Silva; Claus Leth Bak. 2019. "A Current-Based Differential Technique to Detect Loss of Field in Synchronous Generators." IEEE Transactions on Power Delivery 35, no. 2: 514-522.
This paper presents a selective harmonic-based pilot protection scheme for detecting faults happened in the DC transmission section of VSC-MTDC grids with pulse width modulation (PWM) voltage source converters (VSCs). When a DC fault occurs in VSC-MTDC grids with PWM converters, first carrier frequency harmonic (FCFH) currents will be generated by all VSCs through the grid. FCFH currents have different flowing directions depending on the characteristics and the location of the fault. According to the characteristics of the existing FCFH in the fault currents, a selective pilot protection algorithm is designed for VSC-MTDC grids. Considering the internal and external DC transmission faults for specific zones, and the circulating flow of FCFH current in the DC link capacitors, the relays cannot detect FCFH currents for external faults, while for the internal faults, FCFH currents are clearly detected. To design the selective protection algorithm, Hilbert-Huang transform (HHT) is used to detect the instantaneous frequency and the instantaneous amplitude of the high frequency intrinsic mode function (IMF)s, which are extracted from the fault current waves. Multiple faults with different characteristics are applied to CIGRE DCS-2 VSC-MTDC grid with two-level and three-level VSCs modeled in PSCAD, and the HHT-based selective protection scheme is designed in MATLAB. According to the results, the proposed algorithm can truly discriminate between internal and external faults.
Mani Ashouri; Filipe Faria Da Silva; Claus Leth Bak. A Harmonic Based Pilot Protection Scheme for VSC-MTDC Grids with PWM Converters. Energies 2019, 12, 1010 .
AMA StyleMani Ashouri, Filipe Faria Da Silva, Claus Leth Bak. A Harmonic Based Pilot Protection Scheme for VSC-MTDC Grids with PWM Converters. Energies. 2019; 12 (6):1010.
Chicago/Turabian StyleMani Ashouri; Filipe Faria Da Silva; Claus Leth Bak. 2019. "A Harmonic Based Pilot Protection Scheme for VSC-MTDC Grids with PWM Converters." Energies 12, no. 6: 1010.
Chengxi Liu; Nan Qin; Kai Sun; Claus Leth Bak. Remote Voltage Control Using the Holomorphic Embedding Load Flow Method. IEEE Transactions on Smart Grid 2019, 10, 6308 -6319.
AMA StyleChengxi Liu, Nan Qin, Kai Sun, Claus Leth Bak. Remote Voltage Control Using the Holomorphic Embedding Load Flow Method. IEEE Transactions on Smart Grid. 2019; 10 (6):6308-6319.
Chicago/Turabian StyleChengxi Liu; Nan Qin; Kai Sun; Claus Leth Bak. 2019. "Remote Voltage Control Using the Holomorphic Embedding Load Flow Method." IEEE Transactions on Smart Grid 10, no. 6: 6308-6319.
Abbas Hasani; Farhad Haghjoo; Filipe Miguel Faria da Silva; Claus Leth Bak. Synchronous Generator Loss of Field Protection: A Real-Time Realistic Framework and Assessment of Some Recently Proposed Methods. IEEE Transactions on Power Delivery 2019, 34, 971 -979.
AMA StyleAbbas Hasani, Farhad Haghjoo, Filipe Miguel Faria da Silva, Claus Leth Bak. Synchronous Generator Loss of Field Protection: A Real-Time Realistic Framework and Assessment of Some Recently Proposed Methods. IEEE Transactions on Power Delivery. 2019; 34 (3):971-979.
Chicago/Turabian StyleAbbas Hasani; Farhad Haghjoo; Filipe Miguel Faria da Silva; Claus Leth Bak. 2019. "Synchronous Generator Loss of Field Protection: A Real-Time Realistic Framework and Assessment of Some Recently Proposed Methods." IEEE Transactions on Power Delivery 34, no. 3: 971-979.