Publications
254 results found
Rois HA, Kunjumuhammed LP, Pal BC, et 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).
Zhao J, Gomez-Exposito A, Netto M, et 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.
Nogueira EM, Portelinha RK, Lourenco EM, et 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.
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.
Cai L, Thornhill NF, Kuenzel S, et 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.
Vuyyuru U, Pal BC, Maiti S, et 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.
Bose U, Chattopadhyay SK, Chakraborty C, et 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.
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.
Singh AK, Pal BC, 2019, Power System Modeling, Simulation, and Control Design, DYNAMIC ESTIMATION AND CONTROL OF POWER SYSTEMS, Publisher: ACADEMIC PRESS LTD-ELSEVIER SCIENCE LTD, Pages: 9-33, ISBN: 978-0-12-814005-5
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Singh AK, Pal BC, 2019, DYNAMIC ESTIMATION AND CONTROL OF POWER SYSTEMS Conclusion, DYNAMIC ESTIMATION AND CONTROL OF POWER SYSTEMS, Publisher: ACADEMIC PRESS LTD-ELSEVIER SCIENCE LTD, Pages: 193-194, ISBN: 978-0-12-814005-5
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Singh AK, Pal BC, 2019, Centralized Dynamic Estimation and Control, DYNAMIC ESTIMATION AND CONTROL OF POWER SYSTEMS, Publisher: ACADEMIC PRESS LTD-ELSEVIER SCIENCE LTD, Pages: 35-60, ISBN: 978-0-12-814005-5
Singh AK, Pal BC, 2019, Control Based on Dynamic Estimation: Linear and Nonlinear Theories, DYNAMIC ESTIMATION AND CONTROL OF POWER SYSTEMS, Publisher: ACADEMIC PRESS LTD-ELSEVIER SCIENCE LTD, Pages: 121-140, ISBN: 978-0-12-814005-5
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Singh AK, Pal BC, 2019, Decentralized Nonlinear Control Using DSE & Normal Forms, DYNAMIC ESTIMATION AND CONTROL OF POWER SYSTEMS, Publisher: ACADEMIC PRESS LTD-ELSEVIER SCIENCE LTD, Pages: 165-191, ISBN: 978-0-12-814005-5
Singh AK, Pal BC, 2019, Decentralized Dynamic Estimation Using CTs/VTs, DYNAMIC ESTIMATION AND CONTROL OF POWER SYSTEMS, Publisher: ACADEMIC PRESS LTD-ELSEVIER SCIENCE LTD, Pages: 105-119, ISBN: 978-0-12-814005-5
Singh AK, Pal BC, 2019, Decentralized Dynamic Estimation Using PMUs, DYNAMIC ESTIMATION AND CONTROL OF POWER SYSTEMS, Publisher: ACADEMIC PRESS LTD-ELSEVIER SCIENCE LTD, Pages: 61-91, ISBN: 978-0-12-814005-5
Singh AK, Pal BC, 2019, DYNAMIC ESTIMATION AND CONTROL OF POWER SYSTEMS Introduction, DYNAMIC ESTIMATION AND CONTROL OF POWER SYSTEMS, Publisher: ACADEMIC PRESS LTD-ELSEVIER SCIENCE LTD, Pages: 1-8, ISBN: 978-0-12-814005-5
Singh AK, Pal BC, 2019, Dynamic Parameter Estimation of Analogue Voltage and Current Signals, DYNAMIC ESTIMATION AND CONTROL OF POWER SYSTEMS, Publisher: ACADEMIC PRESS LTD-ELSEVIER SCIENCE LTD, Pages: 93-104, ISBN: 978-0-12-814005-5
Singh AK, Pal BC, 2019, Decentralized Linear Control Using DSE and ELQR, DYNAMIC ESTIMATION AND CONTROL OF POWER SYSTEMS, Publisher: ACADEMIC PRESS LTD-ELSEVIER SCIENCE LTD, Pages: 141-164, ISBN: 978-0-12-814005-5
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 inevitably impose increased ancillary service requirements to photovoltaic (PV) plants in the future, including operating reserves. Recent studies have investigated methods to maintain active power reserves without energy storage in the standard case of uniform illumination. In this paper, this functionality is extended to partial shading conditions, often encountered in PV systems. A new control scheme is proposed that permits operation at a reduced power level, estimating at the same time the shading conditions and maximum available power. This is achieved by applying a least-squares curve fitting algorithm on voltage and current measurements, without relying on any irradiance or temperature sensors. To the best of our knowledge, this is the first power reserves control scheme for PV systems under partial shading presented in the literature. The robustness and effectiveness of the proposed method are validated under rapidly changing shading conditions through simulations and experimental tests on a 2-kW PV system prototype.
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.
Ma S, Geng H, Geng Y, et al., 2018, Clustering based coordinated control of large scale wind farm for power system frequency support, IEEE Transactions on Sustainable Energy, Vol: 9, Pages: 1555-1564, ISSN: 1949-3029
This paper proposes a frequency support control scheme for large-scale wind farm (WF) by considering distributed layout of wind turbines (WT) and wake effects inside the WF. The frequency support of WF is formulated as optimization problems. A novel clustering-based optimization method is proposed to coordinate all the WTs so that the whole WF can work at the optimal operating states. In large-scale WF, number of WTs is numerous. With the proposed method, the WTs are first clustered into groups according to their wind profiles. By dispatching the same control commands to the WTs belonging to the same group, each group can be further seen as one single WT. As a result, the number of the WTs and control variables reduces significantly and hence the optimization problems are highly simplified. A case study is carried out to verify the effectiveness of the proposed method.
Cai L, Thornhill NF, Kuenzel S, et al., 2018, Wide-area monitoring of power systems using principal component analysis and k-nearest neighbor analysis, IEEE Transactions on Power Systems, Vol: 33, Pages: 4913-4923, ISSN: 0885-8950
Wide-area monitoring of power systems is important for system security and stability. It involves the detection and localization of power system disturbances. However, the oscillatory trends and noise in electrical measurements often mask disturbances, making wide-area monitoring a challenging task. This paper presents a wide-area monitoring method to detect and locate power system disturbances by combining multivariate analysis known as Principal Component Analysis (PCA) and time series analysis known as k-Nearest Neighbor (kNN) analysis. Advantages of this method are that it can not only analyze a large number of wide-area variables in real time but also can reduce the masking effect of the oscillatory trends and noise on disturbances. Case studies conducted on data from a four-variable numerical model and the New England power system model demonstrate the effectiveness of this method.
Teja AVR, Chakraborty C, Pal BC, 2018, Disturbance rejection analysis and fpga based implementation of a second order sliding mode controller fed induction motor drive, IEEE Transactions on Energy Conversion, Vol: 33, Pages: 1453-1462, ISSN: 0885-8969
This paper presents a unified approach to deal withsliding mode controllers used for induction motor drives. Thestudy digs deep to identify matched and unmatched disturbancesand derive conditions to satisfactorily reject the same. Theinvestigation reveals fundamental limitations of hysteresis (firstorder sliding mode) controllers those can be overcome by higherorder controllers. Second order sliding mode controllers areinvestigated to achieve disturbance rejection and chattering freeperformance. It is shown that the drive with second order slidingmode controllers maintains constant switching frequency anddecoupling between torque and flux simultaneously in the face ofsudden speed, load, or parameter variations. Also, it is shown thatthe dynamic performance can be drastically improved at highersampling frequencies keeping the switching frequency constant.Extensive simulations are carried out in Matlab/Simulink. Imple-mentation of such a drive becomes feasible with low cost FPGAsdue to their inherent parallel processing capability. A vectorcontrolled induction motor drive is developed and the controlleris implemented using FPGA to corroborate the simulation resultsthrough experimentations.
Bhui P, Senroy N, Singh A, et al., 2018, Estimation of inherent governor dead-band and regulation using unscented Kalman filter, IEEE Transactions on Power Systems, Vol: 33, Pages: 3546-3558, ISSN: 0885-8950
The inclusion of the governor droop and dead-band in dynamic models helps to reproduce the measured frequency response accurately and is a key aspect of model validation. Often, accurate and detailed turbine-governor information are not available for various units in an area control centre. The uncertainty in the droop also arise from the nonlinearity due to the governor valves. The droop and deadband are required to tune the secondary frequency bias factors, and to determine the primary frequency reserve. Earlier research on droop estimation did not adequately take into account the effect of dead-band and other nonlinearities. In this paper, unscented Kalman filter is used in conjunction with continuously available measurements to estimate the governor droop and the dead-band width. The effectiveness of the approach is demonstrated through simulations
Anagnostou G, Boem F, Kuenzel S, et al., 2018, Observer-based anomaly detection of synchronous generators for power systems monitoring, IEEE Transactions on Power Systems, Vol: 33, Pages: 4228-4237, ISSN: 0885-8950
This paper proposes a rigorous anomaly detectionscheme, developed to spot power system operational changeswhich are inconsistent with the models used by operators. Thisnovel technique relies on a state observer, with guaranteedestimation error convergence, suitable to be implemented in realtime, and it has been developed to fully address this importantissue in power systems. The proposed method is fitted to thehighly nonlinear characteristics of the network, with the statesof the nonlinear generator model being estimated by meansof a linear time-varying estimation scheme. Given the relianceof the existing dynamic security assessment tools in industryon nominal power system models, the suggested methodologyaddresses cases when there is deviation from assumed systemdynamics, enhancing operators’ awareness of system operation.It is based on a decision scheme relying on analytical computationof thresholds, not involving empirical criteria which are likely tointroduce inaccurate outcomes. Since false-alarms are guaranteedto be absent, the proposed technique turns out to be very usefulfor system monitoring and control. The effectiveness of theanomaly detection algorithm is shown through detailed realisticcase studies in two power system models.
Nduka O, Pal BC, 2018, Quantitative evaluation of actual loss reduction benefits of a renewable heavy DG distribution network, IEEE Transactions on Sustainable Energy, Vol: 9, Pages: 1384-1396, ISSN: 1949-3029
Modern distribution network architectures havegreatly changed due to the increasing proliferation of the networkwith power converters of renewable distributed generators(RDGs) and switching electronic loads. While these RDGs mayoffer benefits to the distribution network operator (DNO) interms of network loss reduction, the quantification of suchbenefits are usually investigated on the basis that harmonicsfrom the power converters are negligible. In this work, theelectrical power losses in a network with significant penetrationof photovoltaics (PVs) is assessed. The harmonics from the powerconditioners of the PVs and network background distortions havebeen taken into account in the analysis. Technical insights fromstudy of practical distribution networks are presented.
Batzelis E, Anagnostou G, Pal B, 2018, A state-space representation of irradiance-driven dynamics in two-stage photovoltaic systems, IEEE Journal of Photovoltaics, Vol: 8, Pages: 1119-1124, ISSN: 2156-3381
In electric grids with large photovoltaic (PV) integration, the PV system dynamics triggered by irradiance variation is an important factor for the power system stability. Although there are models in the literature that describe these dynamics, they are usually formulated as block diagrams or flowcharts and employ implicit equations for the PV generator, thus requiring application-specific software and iterative solution algorithms. Alternatively, to provide a rigorous mathematical formulation, a state-space representation of the PV system dynamics driven by irradiance variation is presented in this paper. This is the first PV dynamic model in entirely state-space form that incorporates the maximum power point tracking function. To this end, the Lambert W function is used to express the PV generator's equations in an explicit form. Simulations are performed in MATLAB/Simulink to evaluate and compare the proposed dynamic model over the detailed switching modeling approach in terms of accuracy and computational performance.
Xuan G, Kuenzel STGI, Pal BC, 2018, Optimal wind farm cabling, IEEE Transactions on Sustainable Energy, Vol: 9, Pages: 1126-1136, ISSN: 1949-3029
Wind farm cable length has a direct impact on the project cost, reliability and electrical losses. The optimum cable layout results in a lower unit cost of generating electricity offshore. This paper explores three cabling structures: the string structure, ring structures and multi-loop structure on a 3D seabed. The newly proposed multi-loop structure increases reliability and proves to be most economic when the failure rate and mean time to repair (MTTR) of cables are relatively high. Particle swarm optimization (PSO) is used to find the optimal substation location that minimizes the overall cable distance.
Basak S, Chakraborty C, Pal BC, 2018, A new configuration of dual stator induction generator employing series and shunt capacitors, IEEE Transactions on Energy Conversion, Vol: 33, Pages: 762-772, ISSN: 0885-8969
Doubly-fed induction generators are suitable for systems having limited speed range as the overall control can be carried out by fractionally-rated converters. However, brushes and slip-rings used in these generators reduce system reliability and demand greater maintenance. Dual stator winding induction generator(DSWIG), being brushless, removes this limitation. Two distributed windings are embedded in the stator and the rotor is squirrel-cage. One of the windings is interfaced to an uncontrolled rectifier and the other to a fractionally rated PWM converter. Uncontrolled rectifier degrades the power quality within the generation system. At the same time, reactive power demand in induction generators increases with loading. This work deals with design and control of a standalone dc system based on DSWIG where a combination of passive tuned filter and series capacitor is utilised to address the voltage regulation and power quality issue. Simulation results using MATLAB/Simulink and experimental results (obtained from a laboratory prototype) have been presented, compared and discussed to demonstrate the effectiveness of the proposed alternative.
Schneider KP, Mather BA, Pal BC, et al., 2018, Analytic considerations and design basis for the IEEE distribution test feeders, IEEE Transactions on Power Systems, Vol: 33, Pages: 3181-3188, ISSN: 0885-8950
For nearly 20 years the Test Feeder Working Group of the Distribution System Analysis Subcommittee has been developing openly available distribution test feeders for use by researchers. The purpose of these test feeders is to provide models of distribution systems that reflect the wide diversity in design and their various analytic challenges. Because of their utility and accessibility, the test feeders have been used for a wide range of research, some of which has been outside the original scope of intended uses. This paper provides an overview of the existing distribution feeder models and clarifies the specific analytic challenges that they were originally designed to examine. Additionally, the paper will provide guidance on which feeders are best suited for various types of analysis. The purpose of this paper is to provide the original intent of the Working Group and to provide the information necessary so that researchers may make an informed decision on which of the test feeders are most appropriate for their work.
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