kumars rouzbehi | University of Seville (original) (raw)

Papers by kumars rouzbehi

IET Energy Systems Integration, 2020

Power systems are subjected to various types of faults as well as ferroresonance overvoltages. Th... more Power systems are subjected to various types of faults as well as ferroresonance overvoltages. These result in the interruption of the normal operation of the power grid, failure of equipment, electrical fires, etc. To tackle these issues, this paper proposes a dual function limiter to control the fault current and ferroresonance phenomenon in power systems. This compound device is a solid-state series transformer-based limiter that includes IGBT switches, capacitor, rectifiers, and a DC reactor. During the grid normal operation, the proposed limiter is not active and therefore is invisible and it operates in the instant of fault inception or ferroresonance overvoltage occurrences. Analytical studies in all operation modes are presented and assessments on the performance of the proposed ferroresonance and fault current limiter (FFCL) are conducted in Matlab. Simulation results confirm the reported analytical studies and FFCL´s performance.

IET Renewable Power Generation

2019 30th Irish Signals and Systems Conference (ISSC)

This paper presents a type of solar thermal power plant and also studies the efficiency of the co... more This paper presents a type of solar thermal power plant and also studies the efficiency of the common type of this distributed generation resource. In order to improve the efficiency of the power station, several techniques are studied such as the combined cycle plant, the thermoelectric generator and the intelligent control application. The thermodynamic analysis of the power plant and the performance of the equipment with an intelligent control system are validated by the developed experimental prototype.

2018 Smart Grid Conference (SGC)

In this paper, a general representation of multi terminal VSC-HVDC based microgrids appropriate f... more In this paper, a general representation of multi terminal VSC-HVDC based microgrids appropriate for power flow studies using Newton-Raphson method is developed and presented. To such aim, active loads and ideal synchronous machines are employed in order to incorporate both converter losses and power balance, respectively. The proposed representation takes into account the practical limitations, switching and conduction losses of semiconductors and the different VSC-HVDC stations control strategies. Moreover, the proposed generalized representation of VSC-HVDC systems can be easily extended to incorporate multi terminal VSC-HVDC based microgrids in an efficient manner. The proposed representation for VSC-HVDC systems and load flow solution are applied to a test system, followed by discussion on results of written computer program. Results show the proposed algorithm is able to solve ac/dc power flow problems with considerable less time in comparison to other existing algorithms. Developed presentation for multi-terminal VSC-HVDC can be effectively applied to power flow solution of AC and DC microgrids.

2020 22nd European Conference on Power Electronics and Applications (EPE'20 ECCE Europe)

This paper aims to develop a control technique for grid-interfaced voltage source converters in d... more This paper aims to develop a control technique for grid-interfaced voltage source converters in distributed power generation systems. The proposed method is composed of two control loops, i.e., inner and outer controllers. The former one is based on a fast current control technique, with the capability of handling active and reactive power. The inertial characteristic of conventional synchronous generators is mimicked by means of the outer control loop, with the aim of providing required inertia for the main grid. This developed control strategy results in mitigation of frequency nadir and rate of change of frequency level in the system frequency response, and thereby, frequency stability during disturbances. Herein, the dynamics of the suggested control scheme is first presented in the dq rotating frame for the design of current control loops. Virtual inertia emulation using the frequency-power response based topology is then discussed in detail. Finally, a 200 kVA virtual synchronous generator is simulated in MATLAB to support theoretical analyses and demonstrate the appropriate performance of the suggested technique in control of interfaced voltage source converters between distributed energy sources and power grids.

2019 10th International Power Electronics, Drive Systems and Technologies Conference (PEDSTC)

Power transmission technology of the offshore wind farm (OWF)s is usually based on HVDC interconn... more Power transmission technology of the offshore wind farm (OWF)s is usually based on HVDC interconnection. Power flow controller (PFC)s are flexible power transmission devices which play important role in the DC power flow (PF) control especially in contingency conditions. So, these devices should be modeled to solve related MT-HVDC grid DC PF equations. In this context, an interline DC PFC (IDC-PFC) is considered as a sample PFC for modeling due to its advantages in comparison to other series and cascaded PFCs. The novelty of this work is solving the DC PF problem of the IDC-PFC compensated MT-HVDC grids by modeling of the IDC-PFC and employing the Newton-Raphson (N-R) method. An eight-bus MT-HVDC test grid is considered to authenticate the presented IDC-PFC modeling and verify the accuracy of the DC PF results obtained by employing the N-R method. The obtained static results verify the accuracy of the presented IDC-PFC modeling and the performance of the N-R method in solving flexible MT-HVDC grid PF equations. Hence, it is suitable to integrate them in the future power system analysis softwares.

2020 28th Iranian Conference on Electrical Engineering (ICEE)

DC power flow controller (PFC)s are suitable equipment to provide secure/reliable operation of th... more DC power flow controller (PFC)s are suitable equipment to provide secure/reliable operation of the multiterminal HVDC (MT-HVDC) networks. Also, they enhance the controllability of these grids. This paper proposes a new representation of the Newton-Raphson (NR) based DC power flow (PF) solver to provide suitable DC PF studies of PFC compensated/flexible MT-HVDC grids. To achieve this aim, the power injection model (PIM) (under static condition) for an interline DC PFC (IDC-PFC) is proposed and embedded within the presented DC PF solver (DC-PFS) while the symmetry and original framework of the conductance matrix of the system is yet preserved and the proposed concept imposes a few changes on the related Jacobin matrix. In the proposed model, resistive shunt admittance of HVDC lines is also taken into account. Modifying the physical and control state variables of the whole system (IDC-PFC and MT-HVDC grid) in a common collaboration, the predetermined control objective(s) are obtained. The accurate concept and effectiveness of the presented IDC-PFC models and new representation of the NR-based DC-PFS are verified by performing dynamic and static simulations on an 8-bus MT-HVDC test network.

7th Iran Wind Energy Conference (IWEC2021)

Wind energy has always been developed as one of the vital parts of modern power systems. However,... more Wind energy has always been developed as one of the vital parts of modern power systems. However, by integration of wind-based generation, the level of fault current is likely to be increased which can damage the wind generators, microgrid components, and upstream grids. Consequently, utilizing viable protecting structures might preserve wind generator structures and other sections of the electric system as well. In this paper, first, the issue of the fault current of wind generators is discussed, and then well-known solution for protecting wind generators against fault current will be classified based on the comprehensive review. Next, various power electronic-based structures which are proper for protection of systems against the fault current, will be debated and ultimately the features of reviewed structures will be compared and summarized in a table for the case of wind energy generator protection.

2016 IEEE Energy Conversion Congress and Exposition (ECCE)

2020 2nd Global Power, Energy and Communication Conference (GPECOM), 2020

In this paper, a grid-connected hybrid DC/AC microgrid including a PV-based DC/DC converter, a bi... more In this paper, a grid-connected hybrid DC/AC microgrid including a PV-based DC/DC converter, a bidirectional Lithium Battery (LB)-based DC/DC converter and a grid-connected DC/AC converter is controlled by proposing various linear compensators embedded in the inner dynamics of the used power converters. The proposed control strategies are designed for the power converters in such a way that all DC-link voltage fluctuations are instantaneously combined with other parts of closed-loop systems through suitable compensators design. The best performance for the compensators components is achieved by evaluating the natural frequencies and amplitude of transfer functions realized from the proposed control techniques-based closed-loop systems. To assess the proposed control technique performance, comparative simulation results in MATLAB/SIMULINK are presented to verify desired DClink voltage, the appropriate control of DC/DC power converters output currents, AC grid stability, and accurate ...

IECON 2017 - 43rd Annual Conference of the IEEE Industrial Electronics Society

This study deals with impacts of the shunt conductances associated with HVDC cables and VSC-HVDC ... more This study deals with impacts of the shunt conductances associated with HVDC cables and VSC-HVDC stations on optimal operation of Multi-Terminal HVDC (MT-HVDC). In this study, for the first time, shunt conductances are integrated to HVDC Optimal Power-Flow (OPF) program that is executed at the Power Dispatch Center (PDC) of the MT-HVDC grid. With the objective of losses minimization, optimal reference operation points of the VSC-HVDC stations are derived. The operating points of the power converter stations are adjusted based on the calculations performed in the dispatch center. CIGRE DCS3 MT-HVDC grid, structured by CIGRE B4 working group, is taken as the test platform. Test results have revealed the optimum voltages and loss pattern change. Moreover, the findings are compared with the case of neglecting the shunt conductances.

IEEE Journal of Emerging and Selected Topics in Power Electronics

Electric Power Systems Research

Abstract Rational function-based models have proved to be very efficient for accurate frequency-d... more Abstract Rational function-based models have proved to be very efficient for accurate frequency-dependent modeling of power system components. These models are able to characterize the components terminal behaviours (analysing the admittance matrix) for nodal analysis. This provides a fast convergence and inherent stability to the solution routine of the model. This work presents a general framework for interfacing the dynamic phasor method to the rational models. That would be promising for the electromagnetic transient analysis (under harmonic distortion), in the frequency domain. Therefore, Y-element rational pole-residue models (employing the vector fitting method) are developed. Moreover, the pole-residue model is converted into the state-space representation. Next, the dynamic harmonic approach (in the frequency domain) is employed for harmonic analysis. It is shown that the order of state-space system can become a major concern for frequency-dependent networks analysis. Therefore, to generate a reduced-order model, the balanced realization theory is applied. Moreover, (for the sake of simplicity and efficiency) the trapezoidal integration rule is employed to discretise the state-space equations. For validation of the modelling, it is applied on three test case studies and results of these studies are compared with their time-domain analysis results.

IEEE Transactions on Power Electronics

High Voltage Direct Current (HVDC) systems are now well-integrated into AC systems in many jurisd... more High Voltage Direct Current (HVDC) systems are now well-integrated into AC systems in many jurisdictions. The integration of Renewable Energy Sources (RESs) is a major focus and the role of HVDC systems is expanding. However, the protection of HVDC systems against DC faults is a challenging issue that can have negative impacts on the reliable and safe operation of power systems. Practical solutions to protect HVDC grids against DC faults without a widespread power outage include (1) using DC Circuit Breakers (CBs) to isolate the faulty DC-link, (2) using a proper converter topology to interrupt the DC fault current, and/or (3) using high power DC transformers and DC hubs at strategic points within DC grids. The application of HVDC CBs is identified as the best approach that satisfies both DC grids and connected AC grids' requirements. This paper reports a comprehensive review of HVDC CBs technologies, including recent significant attempts in the development of modern HVDC CBs. The functional analysis of each technology is presented. Additionally, different technologies based on information obtained from literature are compared. Finally, recommendations for the improvement of CBs are presented.

2019 IEEE PES Innovative Smart Grid Technologies Europe (ISGT-Europe), 2019

Hybrid HVDC links incorporate both Line Commutated Converters (LCC) and Voltage Source Converters... more Hybrid HVDC links incorporate both Line Commutated Converters (LCC) and Voltage Source Converters (VSC) systems, thereby gathering the benefits of both technologies. Supplementary Power Oscillation Damping (POD) controllers can be added to both LCCs and VSCs to help enhance the power system stability against disturbances, such as short circuits. However POD controller tuning can be a delicate process, due to the highly non-linear and complex nature of the involved power system, which might induce adverse interactions leading to a reduced damping. This paper proposes the application of the Simulated Annealing Algorithm (SAA) for tuning the POD controllers parameters, with the purpose of optimizing the performance of POD controllers in the power system. The damping performance is evaluated in case of multiple disturbances in a test power system. The results show the ability of the proposed technique to enhance the performance of the POD controllers under various operating conditions.

In recent years, there have been considerable efforts in the design and development of technologi... more In recent years, there have been considerable efforts in the design and development of technologies and techniques for more efficient harvesting of renewable energy resources to meet the ever increasing electric power demand and to limit the use of fossil fuels. In this regard, offshore wind farms have emerged as a promising solution, particularly in the North Sea, due to the vast potential of offshore wind energy. Large-scale offshore wind farms in the North Sea pose grid integration challenges such as the need for long distance submarine power transmission and managing the harvested wind energy. These challenges can be properly addressed by developing of Multi terminal dc (MTDC) systems. Future MTDC grids are expected to be built overlaying the present ac grids as well as harvesting offshore wind to build so-called "Supergrid" The work presented in this dissertation is oriented to facilitate the control and operation of future MTDC grids. The proposed approaches rely on ...

Energies

Several types of high voltage direct current (HVDC) breakers have been introduced and commerciali... more Several types of high voltage direct current (HVDC) breakers have been introduced and commercialized. Each of them has advantages and disadvantages. Among them, the hybrid HVDC breaker is highly successful. One of the most important concerns that the hybrid HVDC breaker has faced is high power loss throughout its fault current breaking process. The hybrid HVDC breaker comprises a high voltage bidirectional main HVDC breaker. A significant number of electronic switches need to be connected in a series where anti-parallel diodes are essentially embraced. During fault inception, a number of series solid-state switches and a number of series diodes dramatically increase the power loss of the main breaker. This study, firstly, studies the power loss of the hybrid HVDC breaker and later develops a structure of a full-bridge hybrid breaker (FBHB) to reduce the losses of the current structure both in the normal and fault protection states. In this paper simulations are done based on PSCAD. ...

Applied Sciences

The integration of offshore wind farms has revitalized the interest in multi–terminal high voltag... more The integration of offshore wind farms has revitalized the interest in multi–terminal high voltage direct current (M–HVdc) transmission grids. HVdc breakers’ importance has increased as M–HVdc grids are now a commercial truth. Several HVdc circuit breaker technologies have been developed, published, and appeared as prototypes for HVdc networks. This paper summarizes the HVdc breaker technologies from the last two decades, distributed mainly in literature. A comparison of various state–of–the–art HVdc breakers is presented. Further, areas are identified where further research and development are required. The goal is to provide primary challenges and prospects in the HVdc breaker field.

Electrical Engineering (ICEE), Iranian Conference on

This paper addresses a key concern about insufficient inertia in future power systems characteriz... more This paper addresses a key concern about insufficient inertia in future power systems characterized by high penetration of renewable energy sources. In this regard, effective provision of inertial support from a Synchronous Power Controlled (SPC) Type 4 Wind Turbine (WT) is investigated by emulating electrochemical and electrical characteristics of a typical synchronous generator. The kinetic energy possessed by WTs rotary masses is excavated to supply the inertial power offered by SPC solution as the main contribution and hence eliminate the need for installing extra energy storage device. In this regard, a restructured control framework is proposed that the role of dc-link voltage control and maximum power point tracking are assigned to machine and SPC based grid side power converters respectively. Based on Real-Time Digital Simulator results (frequency sweep test), the feasibility of the proposed control framework along with the influence of key control parameters on the dynamic frequency support characteristics are evaluated.