Imperial College London

ProfessorBikashPal

Faculty of EngineeringDepartment of Electrical and Electronic Engineering

Professor of Power Systems
 
 
 
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Contact

 

+44 (0)20 7594 6172b.pal Website CV

 
 
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Assistant

 

Miss Guler Eroglu +44 (0)20 7594 6170

 
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Location

 

1104Electrical EngineeringSouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
to

198 results found

Kumar CS, Rajawat K, Chakrabarti S, Pal BCet al., 2020, Robust distribution system state estimation with hybrid measurements, IET GENERATION TRANSMISSION & DISTRIBUTION, Vol: 14, Pages: 3250-3259, ISSN: 1751-8687

Journal article

Gupta Y, Doolla S, Chatterjee K, Pal BCet al., 2020, Optimal DG Allocation and Volt–var Dispatch for a Droop Based Microgrid, IEEE Transactions on Smart Grid, Pages: 1-1, ISSN: 1949-3053

Journal article

Nsengiyaremye J, Pal BC, Begovic MM, 2020, Microgrid protection using low-cost communication systems, IEEE Transactions on Power Delivery, Vol: 35, Pages: 2011-2020, ISSN: 0885-8977

Power electronics interface of renewable energy to system is now the trend in both transmission and distribution segments of power network. Unlike synchronous generators, the fault feeding and control characteristic of these renewable generators are different and mostly influenced by the topology, switching, and control deployed in power electronics interface. So, the network protection design and operational requirements are now challenged in the absence of large fault current. Although the differential current principle still works, its implementation is limited by the significant cost associated to its communication system. This paper proposes a differential line protection scheme based on local fault detection and comparing binary state outputs of relays at both ends of the line thus requiring a simple, flexible and low bandwidth communication system. The performance of the proposed scheme is assessed through simulation of an example system with several scenarios.

Journal article

Merritt NR, Chakraborty C, Bajpai P, Pal BCet al., 2020, A unified control structure for grid connected and islanded mode of operation of voltage source converter based distributed generation units under unbalanced and non-linear conditions, IEEE Transactions on Power Delivery, Vol: 35, Pages: 1758-1768, ISSN: 0885-8977

This manuscript develops a unified control structure for Distributed Generation (DG) units based on Voltage Source Converters considering unbalanced and non-linear operating conditions. This control structure works for both the Islanded and the Grid-connected modes of operation of the Micro-Grid (MG). The objective of this control scheme is to regulate the line currents of the DG unit in such a manner that the voltage at the Point of Common Coupling (PCC) remains balanced despite the line currents of the DG unit being unbalanced and distorted. Multiple adaptive P-R controllers have been proposed for the current control loop of the Voltage Source Converter (VSC). These controllers have been implemented with resettable integrators so as to limit the DC components in the post fault current of the VSC. The Battery Energy Storage System (BESS) is interfaced to the DC link of the VSC through bi-directional dc-dc converters. An improved control structure for the bi-directional dc-dc converter has been developed. The effectiveness of these control structures have been presented and tested in PSCAD/EMTDC in an IEEE 34 node distribution system model being fed by two identical DG units.

Journal article

X H, Hua G R L, Pal BC, 2020, Transient stability analysis and enhancement of renewable energy conversion system during LVRT, IEEE Transactions on Sustainable Energy, Vol: 11, Pages: 1612-1623, ISSN: 1949-3029

Grid-connected renewable energy conversion systems (RECSs) are usually required by grid codes to possess the low voltage ride through (LVRT) and reactive power support capabilities so as to cope with grid voltage sags. During LVRT, RECS's terminal voltage becomes sensitive and changeable with its output current, which brings a great challenge for the RECS to resynchronize with the grid by means of phase-locked loops (PLLs). This paper indicates that loss of synchronism (LOS) of PLLs is responsible for the transient instability of grid-connected RECSs during LVRT, and the LOS is essentially due to the transient interaction between the PLL and the weak terminal voltage. For achieving a quantitative analysis, an equivalent swing equation model is developed to describe the transient interaction. Based on the model, the transient instability mechanism of RECSs during LVRT is clarified. Furthermore, a transient stability enhancement method is proposed to avoid the possibility of transient instability. Simulations performed on the New England 39-bus test system verify the effectiveness of the method.

Journal article

Pal B, 2020, Successful publications: where the best intentions of all meet [Leader's Corner], IEEE Power and Energy Magazine, Vol: 18, Pages: 12-16, ISSN: 1540-7977

Reports on the Open Access (OA) initiative and efforts by IEEE to launch OA publications.

Journal article

Ali H, Pal B, Model order reduction of multi-terminaldirect-current grid systems, IEEE Transactions on Power Systems, ISSN: 0885-8950

Journal article

Nduka O, Yu YUE, Pal BC, Okafor ENCet al., 2020, A robust augmented nodal analysis approach to distribution network solution, IEEE Transactions on Smart Grid, Vol: 11, Pages: 2140-2150, ISSN: 1949-3053

The ambition to decarbonize the source of energy for heat and transport sector through electricity from renewable energy has led to significant challenge in the way power distribution networks (DNs) are planned, designed and operated. Traditionally, DN was put in place to support the demand passively. Now with renewable generation, storage and demand side management through automation, provision of network support services have transformed the character of the DNs. Active management of the DN requires fast power flow analysis, state estimation, reactive power support etc. This paper proposes a method of power flow analysis which incorporates the challenges of distributed generator (DG) characteristics, demand side management and voltage support. The proposed approach reformulated the Jacobian matrix of the well-known modified augmented nodal analysis (MANA) method; thus, improving the robustness and solvability of the formulation. Reactive powers of the DGs, node voltages and currents of ‘non-constitutive’ elements were the chosen state variables. The performance of this method is compared with the MANA. Results are discussed and the effectiveness of the proposed approach is demonstrated with two example case studies.

Journal article

Ul-Nazir F, Kumar N, Pal BC, Singh B, Panigrahi BKet al., 2020, Enhanced SOGI controller for weak grid integrated solar PV system, IEEE Transactions on Energy Conversion, Vol: 35, Pages: 1208-1217, ISSN: 0885-8969

This paper presents a two-stage three-phase solar photovoltaic (PV) system, which is controlled through a novel enhanced second order generalized integrator (ESOGI) based control technique. The proposed ESOGI is used for fundamental component extraction from nonlinear load current and distorted grid voltages. The proposed integrator effectively and simultaneously manages to address the DC offset, inter-harmonic and integrator delay problems of the traditional SOGI. In addition, the proposed control technique provides power factor correction, harmonic elimination, and load balancing functionalities. The ESOGI controller is used to generate reference grid currents for controlling the voltage source converter (VSC), interfacing the PV panel with the grid. Extensive simulation and experimental results, on a developed prototype in the laboratory, depict that the total harmonic distortion (THD) of the grid injected currents and voltages are found well under IEEE-519 standard.

Journal article

Batzelis EI, Anagnostou G, Chakraborty C, Pal BCet al., 2020, Computation of the lambert W function in photovoltaic modeling, Electrimacs 2019, Publisher: Springer International Publishing, Pages: 583-595, ISSN: 1876-1100

Recently, the Lambert W function has emerged as a valuable mathematical tool in photovoltaic (PV) modeling and other scientific fields. This increasing interest is because it can be used to reformulate the implicit equations of the single-diode PV model into explicit form. However, the computation of the Lambert W function itself is still not clear in the literature; some studies use the iterative built-in functions in MATLAB or other computational platforms, while others adopt their own approximation formulae. This paper takes a deeper look at the ways the Lambert W function is evaluated in PV models and carries out a comparative study to assess the most commonly used methods in terms of accuracy, computational cost, and application range. These alternatives are implemented in a modern computer and a typical microcontroller to evaluate their performance in both simulations and embedded applications. The analysis concludes that some series expansions are good options for PV modeling applications, requiring less execution time than the built-in MATLAB lambertw function and exhibiting negligible approximation error.

Conference paper

Chen Y, Mazhari SM, Chung CY, Faried S, Pal BCet al., 2020, Rotor angle stability prediction of power systems with high wind power penetration using a stability index vector, IEEE Transactions on Power Systems, ISSN: 0885-8950

This paper proposes a methodology for predicting online rotor angle stability in power system operation under significant contribution from wind generation. First, a novel algorithm is developed to extract a stability index (SI) that quantifies the margin of rotor angle stability of power systems reflecting the dynamics of wind power. An approach is proposed that takes advantage of the machine learning technique and the newly defined SI. In case of a contingency, the developed algorithm is employed in parallel to find SIs for all possible instability modes. The SIs are formed as a vector and then applied to a classifier algorithm for rotor angle stability prediction. Compared to other features used in state-of-the-art methods, SI vectors are highly rec-ognizable and thus can lead to a more accurate and reliable prediction. The proposed approach is validated on two IEEE test systems with various wind power penetration levels and compared to existing methods, followed by a discussion of results.

Journal article

Rois H, Kunjumuhammed LPK, Pal BC, Adamczyk A, Vershinin Ket al., 2020, A trajectory piecewise-linear approach to nonlinear model order reduction of wind farms, IEEE Transactions on Sustainable Energy, Vol: 11, Pages: 894-905, ISSN: 1949-3029

This paper presents a method to develop computationally efficient dynamic model of a wind farm suitable for large disturbance simulation. The method based on a Trajectory Piecewise Linear (TPWL) approximation uses single and multiple training trajectory to develop a nonlinear reduced order model (ROM). Simulation results using a small demonstration wind farm system and a large practical wind farm system are discussed to demonstrate the effectiveness of the model in capturing dynamic behaviour of wind farm following large disturbances.

Journal article

Nduka OS, Kunjumuhammed L, Pal B, Majumdar A, Yu Y, Maiti S, Ahmadi Aet al., 2019, Field trial of coordinated control of PV and energy storage units and analysis of power quality measurements, IEEE Access, Vol: 8, Pages: 1962-1974, ISSN: 2169-3536

Trends support low voltage distribution networks will soon experience significant uptake of customer-owned low-carbon technology (LCT) devices especially rooftop photovoltaics (PVs) and small-scale energy storage (SSES) systems. This paradigm shift will introduce some significant challenges in modern distribution network planning and operations owing to the temporal nature of modern demand.Therefore, it became relevant to investigate the UK low voltage (LV) network operations considering high uptake of PVs and SSESs through both field measurements and desktop studies. The aim was to validatethrough field trials, the flexibility benefits of peak demand reduction and reverse power flow mitigation through smart control of customer-owned SSESs. It was shown that peak demand of up to 60% could beachieved in UK distribution network through the smart control of these devices. In tandem with the demand reduction, the study revealed that type-tested SSES power interface units do not pose significant powerquality risks even for 100% customer penetration.

Journal article

Kumar S, Singh B, Pal BC, Xu L, Al-Durra Aet al., 2019, Energy efficient three-phase utility interactive residential microgrid with Mode transfer capabilities at weak grid conditions, IEEE Transactions on Industry Applications, Vol: 55, Pages: 7082-7091, ISSN: 0093-9994

This article presents an energy efficient autonomous grid-synchronized photovoltaic (PV) array battery energy storage (BES) based microgrid with power quality improving capabilities under weak grid conditions. The microgrid is developed to supply consumer loads even at disappearance of the weak grid. The BES is not only beneficial on daily energy saving but it is also sized to furnish smoothening facilities to the PV-BES microgrid. A pseudolinear synchronization scheme is used, which is based on extraction of fundamental positive sequence components from the polluted grid voltages. The islanded controller furnishes reliability by maintaining the voltage and frequency and continuous power to the consumer load. The multivariance generalized adaptive controller is proposed to control the microgrid and to improve the power quality aspects. The effectiveness of microgrid is demonstrated experimentally with estimation of phase and frequency at grid synchronization and desynchronization with polluted grid conditions.

Journal article

Zhang L, Kerrigan E, Pal B, 2019, Optimal communication scheduling in the smart grid, IEEE Transactions on Industrial Informatics, Vol: 15, Pages: 5257-5265, ISSN: 1551-3203

This paper focuses on obtaining the optimal communication topology in the smart grid architecture, i.e. what is the optimal communication setup of smart meters in a smart building. The fact that smart meters also consume energy, more often than not, gets ignored by researchers and engineers. In this paper, we will show that smart meter networks can consume significantly less energy with optimal scheduling. Numerical results show that the overall energy consumption can be reduced by implementing the optimal communication architecture and transmission rate setup, rather than implementing a straightforward communication architecture with uniform channel bandwidth.

Journal article

Anagnostou G, Puthenpurayl Linash K, Pal B, 2019, Dynamic state estimation for wind turbine models with unknown wind velocity, IEEE Transactions on Power Systems, Vol: 34, Pages: 3879-3890, ISSN: 0885-8950

This paper proposes a novel Kalman filtering based dynamic state estimation method, which addresses cases of models with a nonlinear unknown input, and it is suitable for wind turbine model state estimation. Given the complexity characterising modern power networks, dynamic state estimation techniques applied on renewable energy based generators, such as wind turbines, enhance operators’ awareness of the components comprising modern power networks. In this context, the method developed here is implemented on a doubly-fed induction generator based wind turbine, under unknown wind velocity conditions, as opposed to similar studies so far, where all model inputs are considered to be known, and this does not always reflect the reality. The proposed technique is derivative-free and it relies on the formulation of the nonlinear output measurement equations as power series. The effectiveness of the suggested algorithm is tested on a modified version of the IEEE benchmark 68-bus, 16-machine system.

Journal article

Su D, Batzelis E, Pal B, 2019, Machine learning algorithms in forecasting of photovoltaic power generation, 2019 International Conference on Smart Energy Systems and Technologies (SEST), Publisher: IEEE

Due to the intrinsic intermittency and stochastic nature of solar power, accurate forecasting of the photovoltaic (PV) generation is crucial for the operation and planning of PV-intensive power systems. Several PV forecasting methods based on machine learning algorithms have recently emerged, but a complete assessment of their performance on a common framework is still missing from the literature. In this paper, a comprehensive comparative analysis is performed, evaluating ten recent neural networks and intelligent algorithms of the literature in short-term PV forecasting. All methods are properly fine-tuned and assessed on a one-year dataset of a 406 MWp PV plant in the UK. Furthermore, a new hybrid prediction strategy is proposed and evaluated, derived as an aggregation of the most well-performing forecasting models. Simulation results in MATLAB show that the season of the year affects the accuracy of all methods, the proposed hybrid one performing most favorably overall.

Conference paper

Singh AK, Pal BC, 2019, Rate of change of frequency estimation for power systems using interpolated DFT and Kalman filter, IEEE Transactions on Power Systems, Vol: 34, Pages: 2509-2517, ISSN: 0885-8950

This paper presents a new method for estimating rate of change of frequency (RoCoF) of voltage or current signals measured using instrument transformers. The method is demonstrably superior to currently available methods in literature, in terms of estimation-latency and estimation-error. The estimation is performed in two steps. In the first step, the analog voltage or current signal obtained from an instrument transformer is statistically processed using interpolated discrete Fourier transform in order to obtain the means and variances of the signal parameters. These means and variances are then given as inputs to the second step, in which Kalman filtering is used to find the final RoCoF estimate. Accurate mathematical expressions for the means and variances of signal parameters have been derived and used in the second step, which is the main reason behind the superior performance of the method. The applicability of the method has been demonstrated on a benchmark power system model.

Journal article

Rois HA, Kunjumuhammed LP, Pal BC, Adamsczyk A, Vershinin Ket al., 2019, Model order reduction of wind farms: linear approach, IEEE Transactions on Sustainable Energy, Vol: 10, Pages: 1194-1205, ISSN: 1949-3029

This paper presents three types of linear modelorder reduction (MOR) technique, namely singular value de-composition (SVD)-based, Krylov-based, and modal truncation-based type applied to large-scale wind farm models. The firsttype includes a Balanced Truncation (BT) and AlternatingDirection Implicit (ADI)-based BT method, while the secondtype encompasses a Rational Krylov (RK), and Iterative RationalKrylov Algorithm (IRKA) method. In the third type, a SubspaceAccelerated MIMO Dominant Pole Algorithm (SAMDP) methodis used. The effectiveness of these methods are tested on practical-sized wind farms with 90, 120 and 210 doubly-fed inductiongenerators (DFIGs). Merits and demerits of each method arediscussed in detail. The reduced order model (ROM) of windfarm is validated against the full order model (FOM) in term offrequency domain indices and waveform agreement at the pointof common coupling (PCC).

Journal article

Batzelis E, Anagnostou G, Cole I, Betts T, Pal Bet al., 2019, A state-space dynamic model for photovoltaic systems with full ancillary services support, IEEE Transactions on Sustainable Energy, Vol: 10, Pages: 1399-1409, ISSN: 1949-3029

Large-scale photovoltaic (PV) integration to the network necessitates accurate modeling of PV system dynamics under solar irradiance changes and disturbances in the power system. Most of the available PV dynamic models in the literature are scope-specific, neglecting some control functions and employing simplifications. In this paper, a complete dynamic model for two-stage PV systems is presented, given in entirely state-space form and explicit equations that takes into account all power circuit dynamics and modern control functions. This is a holistic approach that considers a full range of ancillary services required by modern grid codes, supports both balanced and unbalanced grid operation, and accounts for the discontinuous conduction mode (DCM) of the dc/dc converter of the system. The proposed dynamic model is evaluated and compared to other approaches based on the literature, against scenarios of irradiance variation, voltage sags and frequency distortion. Simulation results in MATLAB/Simulink indicate high accuracy at low computational cost and complexity.

Journal article

Zhao J, Gomez-Exposito A, Netto M, Mili L, Abur A, Terzija V, Kamwa I, Pal B, Singh AK, Qi J, Huang Z, Meliopoulos APSet al., 2019, Power system dynamic state estimation: motivations, definitions, methodologies, and future work, IEEE Transactions on Power Systems, Vol: 34, Pages: 3188-3198, ISSN: 0885-8950

This paper summarizes the technical activities of the Task Force on Power System Dynamic State and Parameter Estimation. This Task Force was established by the IEEE Working Group on State Estimation Algorithms to investigate the added benefits of dynamic state and parameter estimation for the enhancement of the reliability, security, and resilience of electric power systems. The motivations and engineering values of dynamic state estimation (DSE) are discussed in detail. Then, a set of potential applications that will rely on DSE is presented and discussed. Furthermore, a unified framework is proposed to clarify the important concepts related to DSE, forecasting-aided state estimation, tracking state estimation, and static state estimation. An overview of the current progress in DSE and dynamic parameter estimation is provided. The paper also provides future research needs and directions for the power engineering community.

Journal article

Nogueira EM, Portelinha RK, Lourenco EM, Tortelli OL, Pal BCet al., 2019, Novel approach to power system state estimation for transmission and distribution systems, IET Generation, Transmission and Distribution, Vol: 13, Pages: 1970-1978, ISSN: 1350-2360

This article proposes a power system state estimation (PSSE) capable of dealing with distribution and transmission networks. The proposed approach combines decoupled techniques, complex per unit (cpu) system, and a switching branch representation to meet the increasing complexity of state estimation issue when associated with the emerging electrical systems. The result is an efficient tool that can easily deal with distributed generation, closed loop, or meshed operation and manoeuvres in distribution systems (DS) keeping the efficiency and ability of the fast decoupled estimator to process transmission systems (TS). Results obtained with several simulations carried out on two distribution test systems, a 136-node Brazilian feeder and a 907-node European feeder, and on the IEEE 14-bus TS, demonstrate the effectiveness of the proposed methodology.

Journal article

Kazari H, Oraee H, Pal BC, 2019, Assessing the effect of wind farm layout on energy storage requirement for power fluctuation mitigation, IEEE Transactions on Sustainable Energy, Vol: 10, Pages: 558-568, ISSN: 1949-3029

Optimization of wind farm (WF) layout has been studied in the literature with the objective of maximizing the wind energy capture. Based on the power spectrum density (PSD) theorem, this paper shows that the WF layout affects not only the total harvested energy but also the level of power fluctuation, which in turn influences required capacity of battery energy storage system (BESS) needed to mitigate the inherent power fluctuation of the wind farms. Since both harvested energy level and BESS capacity directly influence the profit of WF owner, the effect of WF layout on these quantities are taken into account simultaneously and WF layout optimization problem is redefined. Genetic algorithm (GA) is then employed in order to optimize the resulting objective function. The proposed method and optimization process are performed on the layout of an actual offshore WF using real wind data. A new index is introduced to quantify the power fluctuations, and energy curtailment is assessed. The comparative analysis between the actual layout performance and the optimal layout in different scenarios is conducted, showing the reduction of power fluctuations and improvement of energy curtailment. In addition, different BESS technologies have been analyzed to study the impact of their parameters on the optimization results.

Journal article

Cai L, Thornhill NF, Kuenzel S, Pal Bet al., 2019, A test model of a power grid with battery energy storage and wide-area monitoring, IEEE Transactions on Power Systems, Vol: 34, Pages: 380-390, ISSN: 0885-8950

This paper presents a test model for investigating how to coordinate a power grid and Energy Storage Systems (ESSs) by Wide-Area Monitoring (WAM). It consists of three parts: (1) a model of a power grid containing different types of generators, loads and transmission network; (2) a model of lithium-ion battery ESSs; (3) a model of multivariate statistical analysis based WAM built to capture the grid information for guiding the operation of ESSs. Simulation studies using a reduced equivalent model specifically built for a UK power grid enhanced with lithium-ion battery ESSs and WAM illustrate the way in which WAM can coordinate a power grid and ESSs, and also demonstrate the benefit of ESSs on a power grid.

Journal article

Vuyyuru U, Pal BC, Maiti S, Chakraborty C, Pal BCet al., 2019, Series voltage regulator for radial DC-microgrid, IEEE Transactions on Sustainable Energy, Vol: 10, Pages: 127-136, ISSN: 1949-3029

The concept of a novel series voltage regulator (SVR) for controlling the dc-bus voltage of a radial dc microgrid is presented in this paper. The proposed SVR uses a dual-active-bridge dc-dc converter followed by a full-bridge dc-dc converter. It injects dynamic voltage in series with the dc grid to compensate resistive drop over the network. As a result, the voltage level at the different points of the grid becomes independent of load variation and stays within the specified limit. Note that the required power rating of the SVR is very low (say 2.7%) compared to the load demand considering 5% voltage regulation. In this paper, the voltage regulator is connected at the midpoint of the grid, but it may be connected in some other locations to get optimal rating of the same. The proposed configuration is simulated in MATLAB/SIMULINK at a 380-V level to check the dynamic performance under various operating conditions. A scaled-down version (at 30-V level) of the proposed system is developed in the laboratory to experimentally validate the concept. The results show the effectiveness of such a voltage regulator for the radial dc microgrid, especially under critical load condition.

Journal article

Ul Nazir F, Pal B, Jabr R, 2019, A two-stage chance constrained volt/var control scheme for active distribution networks with nodal power uncertainties, IEEE Transactions on Power Systems, Vol: 34, Pages: 314-325, ISSN: 0885-8950

Volt/var control (VVC) is one of the primary functions of the distribution management system aiming at optimum operation of power distribution networks while respecting all of their operational and security constraints. However, the recent huge integration of highly stochastic distributed generation (DG) sources with the grid presents a significant challenge to the traditionalVVCschemes,whichassumethefuturetobeperfectly known. This paper presents a two-stage chance constrained optimization scheme to handle these nodal power uncertainties and guarantees that the operational and security constraints are respectedforalmostallrealizationsoftheuncertainty.Thechance constrained model is solved by collecting enough randomly chosen samples from the probability spaces of the uncertain parameters so that the class of the problem, a mixed integer second order cone program (MISOCP), is not elevated. The algorithm not only dispatches the optimum schedule for discrete controlling devices like transformers and shunt capacitors but also optimizes the predefined decision rules for reactive power control of DG sources, thus falling in line with the requirement laid down in the revised IEEE 1547 Standard. Numerical simulations on three different test systems show the superiority of the proposed algorithm over the traditional deterministic methods.

Journal article

Bose U, Chattopadhyay SK, Chakraborty C, Pal BCet al., 2019, A novel method of frequency regulation in microgrid, IEEE Transactions on Industry Applications, Vol: 55, Pages: 111-121, ISSN: 0093-9994

Owing to generation and demand mismatch, thefrequency deviation and the rate of change of frequency (RoCoF)may become drastic at times in an islanded micro-grid. This isdue to increased penetration of non-inertial renewable energysources that brings down the system’s resilience to any kind ofdisturbance. Therefore, efficient control algorithms are requiredto mimic the inertial behavior of a conventional synchronousmachine to arrest/limit any sudden change. This work focuseson frequency regulation of microgrid during transient condi-tions by means of fast-responding external energy reserve. Thecharacteristics of a weak grid has been studied and simulatedthrough modeling a Virtual Synchronous Machine (VSM). Aninverter model is also developed to integrate the Energy StorageSystem (ESS) to the grid and a Double Second-Order GeneralizedIntegrator Phase Locked Loop (DSOGI-PLL) is implementedthat is capable of synchronizing the system under distortedand unbalanced situation. A new technique to estimate thefrequency of the microgrid is reported. A simple proportionalcontroller based approach for different level of pulsed powerinjection (using ultracapacitors and batteries) is proposed andsimulated using MATLAB. Experimental demonstration is madeusing batteries only but with two different current-limits. Thecontroller is implemented using dSPACE1103.

Journal article

Singh AK, Pal BC, 2018, Decentralized Nonlinear Control for Power Systems using Normal Forms and Detailed Models, IEEE-Power-and-Energy-Society General Meeting (PESGM), Publisher: IEEE, ISSN: 1944-9925

Conference paper

Batzelis E, Stavros P, Pal BC, 2018, PV system control to provide active power reserves under partial shading conditions, IEEE Transactions on Power Electronics, Vol: 33, Pages: 9163-9175, ISSN: 0885-8993

The challenges of modern power systems will in-evitably impose increased ancillary service requirements to pho-tovoltaic (PV) plants in the future, including operating reserves.Recent studies investigate methods to maintain active powerreserves without energy storage in the standard case of uniformillumination. In this paper, this functionality is extended to partialshading conditions, often encountered in PV systems. A newcontrol scheme is proposed that permits operation at a reducedpower level, estimating at the same time the shading conditionsand maximum available power. This is achieved by applyinga least squares curve fitting algorithm on voltage and currentmeasurements, without relying on any irradiance or temperaturesensors. To the best of our knowledge, this is the first powerreserves control scheme for PV systems under partial shadingpresented in the literature. The robustness and effectiveness ofthe proposed method is validated under rapidly changing shadingconditions through simulations and experimental tests on a 2 kWPV system prototype.

Journal article

Singh AK, Pal BC, 2018, Dynamic Estimation and Control of Power Systems, Publisher: Academic Press, ISBN: 9780128140062

Dynamic estimation and control is a fast growing and widely researched field of study that lays the foundation for a new generation of technologies that can dynamically, adaptively and automatically stabilize power systems. This book provides a comprehensive introduction to research techniques for real-time estimation and control of power systems.Dynamic Estimation and Control of Power Systems coherently and concisely explains key concepts in a step by step manner, beginning with the fundamentals and building up to the latest developments of the field. Each chapter features examples to illustrate the main ideas, and effective research tools are presented for signal processing-based estimation of the dynamic states and subsequent control, both centralized and decentralized, as well as linear and nonlinear. Detailed mathematical proofs are included for readers who desire a deeper technical understanding of the methods.This book is an ideal research reference for engineers and researchers working on monitoring and stability of modern grids, as well as postgraduate students studying these topics. It serves to deliver a clear understanding of the tools needed for estimation and control, while also acting as a basis for readers to further develop new and improved approaches in their own research.

Book

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