Publications
254 results found
de Souza JCS, Lessa Assis TM, Pal BC, 2015, Data compression in smart distribution systems via singular value decomposition, IEEE Transactions on Smart Grid, Vol: 8, Pages: 275-284, ISSN: 1949-3061
Electrical distribution systems have been experiencingmany changes in recent times. Advances in metering systeminfrastructure and the deployment of a large number of smartmeters in the grid will produce a big volume of data thatwill be required for many different applications. Despite thesignificant investments taking place in the communications infrastructure,this remains a bottleneck for the implementation ofsome applications. This paper presents a methodology for lossydata compression in smart distribution systems using the singularvalue decomposition technique. The proposed method is capableof significantly reducing the volume of data to be transmittedthrough the communications network and accurately reconstructingthe original data. These features are illustrated by resultsfrom tests carried out using real data collected from meteringdevices at many different substations.
Anagnostou G, Pal BC, 2015, Impact of Overexcitation Limiters on the Power System Stability Margin Under Stressed Conditions, IEEE Transactions on Power Systems, Vol: 31, Pages: 2327-2337, ISSN: 1558-0679
This paper investigates the impact of the overexcitation limiters (OELs) on the stability margin of a power system which is operating under stressed conditions. Several OEL modeling approaches are presented and the effect of their action has been examined in model power systems. It is realized that, more often than not, OEL operating status goes undetected by existing dynamic security assessment tools commonly used in the industry. It is found that the identification and accurate representation of OELs lead to significantly different transient stability margins. Unscented Kalman filtering is used to detect the OEL activation events. In the context of stressed system operation, such quantitative assessment is very useful for system control. This understanding is further reinforced through detailed studies in two model power systems.
Agalgaonkar Y, Pal BC, Jabr RA, 2015, Stochastic Distribution System OperationConsidering Voltage Regulation Risks in thePresence of PV Generation, IEEE Transactions on Sustainable Energy, Vol: PP, Pages: 1-10, ISSN: 1949-3037
Variable over voltage, excessive tap counts andvoltage regulator (VR) runaway condition are major operationalchallenges in distribution network while accommodating generationfrom Photovoltaics (PVs). The conventional approach toachieve voltage control based on off-line simulation for voltage setpoint calculation does not consider forecast errors. In this work,a stochastic optimal voltage control strategy is proposed whileconsidering load and irradiance forecast errors. Stochastic operationalrisks such as overvoltage and VR runaway are definedthrough a chance constrained optimization (CCO) problem. Thisclassical formulation to mitigate runaway is further improvedby introducing a stochastic index called the Tap Tail Expectation.Operational objectives such as power losses and excessive tapcount minimization are considered in the formulation. A samplingapproach is proposed to solve the CCO. Along with other voltagecontrol devices, the PV inverter voltage support features arecoordinated. The simulation study is performed using a realisticdistribution system model and practically measured irradianceto demonstrate the effectiveness of the proposed technique.The proposed approach is a useful operational procedure fordistribution system operators. The approach can minimize feederpower losses, avoid voltage violations and alleviate VR runaway.
Nanchian S, Majumdar A, Pal BC, 2015, Three-Phase State Estimation Using Hybrid Particle Swarm Optimization, IEEE Transactions on Smart Grid, Vol: PP, Pages: 1-11, ISSN: 1949-3061
This paper proposes a method for three-phase stateestimation (SE) in power distribution network including on-loadtap changers (OLTC) for voltage control. The OLTC tap positionsare essentially discrete variables from the SE point ofview. Estimation of these variables in SE presents a formidablechallenge. The proposed methodology combines discrete andcontinuous state variables (voltage magnitudes, angles, and tappositions). A hybrid particle swarm optimization (HPSO) isapplied to obtain the solution. The method is tested on standardIEEE 13- and 123-bus unbalanced test system models. Theproposed algorithm accurately estimates the network bus voltagemagnitudes and angles, and discrete tap values. The HPSO-basedtap estimation provides a more accurate estimation of losses inthe network, which helps in fair allocation of cost of losses inarriving at overall cost of electricity
Puthenpurayil Kunjumuhammed L, Pal BC, 2015, Selection of feedback signals for controlling dynamics in future power transmission networks, IEEE Power & Energy Society General Meeting, 2015
This paper deals with the selection of feedback signal(s) that retain the modal behavior of power system electromechanical dynamics under varying operating circumstances. The approach seeks signals that have relatively large magnitude of residue, less variation of the magnitude and phase angle, sufficient gap between the critical pole-zeros, and least sensitive to other modes. The methodology is tested in a 16-machine interconnected power system model with multiple wind farms.
Zhang Y, Larsson M, Pal B, et al., 2015, Simulation approach to reliability analysis of WAMPAC system, 2015 IEEE PES Innovative Smart Grid Technologies Conference (ISGT), Publisher: IEEE, Pages: 1-5
Wide are monitoring, protection and control (WAMPAC) plays a critical role in smart grid development. Since WAMPAC frequently has the tasks of executing control and protection actions necessary for secure operation of power systems, its reliability is essential. This paper proposes a novel approach to the reliability analysis of WAMPAC systems. WAMPAC system functions are first divided into four subsystems: the measured inputs, the communication, the actuator and the analytic execution subsystems. The reliability indices of the subsystems are computed then using Monte Carlo approach. A sensitivity analysis is also described to illustrate the influence of different components on the system reliability.
Ariff MAM, Pal B, Singh A, 2015, Estimating Dynamic Model Parameters for Adaptive Protection and Control in Power System, General Meeting of the IEEE-Power-and-Energy-Society, Publisher: IEEE, ISSN: 1944-9925
Zhang Y, Larsson M, Pal B, et al., 2015, Simulation Approach to Reliability Analysis of WAMPAC System, 2015 IEEE Power & Energy Society Innovative Smart Grid Technologies Conference (ISGT), Publisher: IEEE
Singh AK, Singh R, Pal BC, 2015, Stability Analysis of Networked Control in Smart Grids, General Meeting of the IEEE-Power-and-Energy-Society, Publisher: IEEE, ISSN: 1944-9925
Lourenço EM, Coelho EPR, Pal BC, 2014, Topology Error and Bad Data Processingin Generalized State Estimation, IEEE Transactions on Power Systems, Vol: 30, Pages: 3190-3200, ISSN: 1558-0679
This paper presents a method for processing real-timedata error in generalized state estimation (GSE). Attention is focusedon the two main types of error: network topology errorsand bad data on analog measurements. The proposed approach isable to handle both errors without making any previous assumptionregarding the nature of those errors. The degrading effectsof topology errors over bad data processing when both topologyand measurement errors occur at the same time are evaluated andnew strategy is proposed to overcome it. GSE is treated as a constrainedoptimization problem where measurements and circuitbreakerstatus are modeled as equality constraints.Geometric testsbased on the geometric interpretation of the Lagrange multipliervector are then utilized to determine the source of the error. Theproposed strategy is tested on two model power networks representedat the bus-section level which is derived from the IEEE30-bus and 118-bus systems.
Linash PK, Pal BC, 2014, Selection of Feedback Signals for ControllingDynamics in Future Power Transmission Networks, IEEE Transactions on Smart Grid, Vol: PP, Pages: 1-10, ISSN: 1949-3053
This paper deals with the selection of feedbacksignal(s) that retain the modal behaviour of power system electromechanicaldynamics under varying operating circumstances.The approach seeks signal that has relatively large magnitude ofresidue, less variation of the magnitude and phase angle, sufficientgap between the critical pole-zeros and least sensitive to othermodes. The methodology is tested in a 16-machine interconnectedpower system model with multiple wind farms.
Tortelli OL, Laurenco EM, Garcia AV, et al., 2014, Fast Decoupled Power Flow to Emerging Distribution Systems via Complex pu Normalization, IEEE Transactions on Power Systems, Vol: PP, Pages: 1-8, ISSN: 0885-8950
This paper proposes a generalized approach of the per unit normalization, named complex per unit normalization (cpu), to improve the performance of fast decoupled power flow methods applied to emerging distribution networks. The proposed approach takes into account the changes envisaged and also already faced by distribution systems, such as high penetration of generation sources and more interconnection between feeders, while considering the typical characteristics of distribution systems, as the high R/ X ratios. These characteristics impose difficulties on the performance of both backward-forward sweep and decoupled-based power flow methods. The cpu concept is centred on the use of a complex volt-ampere base, which overcomes the numerical problems raised by the high R/ X ratios of distribution feeders. As a consequence, decoupled power flow methods can be efficiently applied to distribution system analysis. The performance of the proposed technique and the simplicity of adapting it to existing power flow programs are addressed in the paper. Different distribution network configurations and load conditions have been used to illustrate and evaluate the use of cpu.
Ariff MAM, Pal BC, Singh AK, 2014, Estimating Dynamic Model Parameters for Adaptive Protection and Control in Power System, IEEE Transactions on Power Systems, ISSN: 0885-8950
This paper presents a new approach in estimating important parameters of power system transient stability model such as inertia constant H and direct axis transient reactance x′d in real time. It uses a variation of unscented Kalman filter (UKF) on the phasor measurement unit (PMU) data. The accurate estimation of these parameters is very important for assessing the stability and tuning the adaptive protection system on power swing relays. The effectiveness of the method is demonstrated in asimulated data from 16-machine 68-bus system model. The paper also presents the performance comparison between the UKF and EKF method in estimating the parameters. The robustness of method is further validated in the presence of noise that is likely to be in the PMU data in reality.
Singh A, Pal BC, Singh R, 2014, Stability Analysis of Networked Control in Smart Grids, IEEE Transactions on Smart Grid, Vol: 6, Pages: 381-390, ISSN: 1949-3053
A suitable networked control scheme and its stability analysis framework have been developed for controlling inherent electromechanical oscillatory dynamics observed in power systems. It is assumed that the feedback signals are obtained at locations away from the controller/actuator and transmitted over a communication network with the help of phasor measurement units (PMUs). Within the generic framework of networked control system (NCS), the evolution of power system dynamics and associated control actions through a communication network have been modeled as a hybrid system. The data delivery rate has been modeled as a stochastic process. The closed-loop stability analysis framework has considered the limiting probability of data dropout in computing the stability margin. The contribution is in quantifying allowable data-dropout limit for a specified closed loop performance. The research findings are useful in specifying the requirement of communication infrastructure and protocol for operating future smart grids.
Dzafic I, Jabr RA, Halilovic E, et al., 2014, A Sensitivity Approach to Model Local Voltage Controllers in Distribution Networks, IEEE Transactions on Power Systems, Vol: 29, Pages: 1419-1428, ISSN: 0885-8950
Local controllers are essential in distribution networks;they are employed in classical devices such as loadtap-changing (LTC) transformers and switchable shunt capacitors,and more recently in distributed generation (DG). Theeffective use of distribution management system (DMS) applicationsrequires an accurate model of the interaction betweenthe local controllers through the distribution system. This paperpresents a new sensitivity matrix approach for modeling suchinteractions, and demonstrates its application in the implicitGaussmethod for power flow computation. The sensitivity methodmodels both PV buses (for the connection of DG) and tap positionadjustments through current source injections, and consequentlyavoids re-factorization of the network bus admittance matrix.Numerical results on distribution networks with up to 3145 busesshow that the sensitivity-based power flow method for simulatingthe operation of local controllers is superior to a sequentialcontrol action adjustment approach previously proposed in theliterature, and that its computing time is commensurate with theperformance requirements in real-time DMS applications.
kuenzel, Puthenpurayil Kunjumuhammed L, pal, et al., 2014, Impact of wakes on wind farm inertial response, IEEE PES General Meeting | Conference & Exposition, 2014
Singh A, Pal BC, 2014, Decentralized Dynamic State Estimation in Power Systems Using Unscented Transformation, IEEE Transactions on Power Systems, Vol: 29, Pages: 794-804, ISSN: 0885-8950
This paper proposes a decentralized algorithm for real-time estimation of the dynamic states of a power system. The scheme employs phasor measurement units (PMUs) for the measurement of local signals at each generation unit, and subsequent state estimation using unscented Kalman filtering (UKF). The novelty of the scheme is that the state estimation at one generation unit is independent from the estimation at other units, and therefore the transmission of remote signals to a central estimator is not required. This in turn reduces the complexity of each distributed estimator, and makes the estimation process highly efficient, accurate and easily implementable. The applicability of the proposed algorithm has been thoroughly demonstrated on a representative model.
Jabr RA, Dzafic I, Pal BC, 2014, Robust Optimization of Storage Investment on Transmission Networks, IEEE Transactions on Power Systems, Vol: 30, Pages: 531-539, ISSN: 0885-8950
This paper discusses the need for the integration of storage systems on transmission networks having renewable sources, and presents a tool for energy storage planning. The tool employs robust optimization to minimize the investment in storage units that guarantee a feasible system operation, without load or renewable power curtailment, for all scenarios in the convex hull of a discrete uncertainty set; it is termed ROSION—Robust Optimization of Storage Investment On Networks. The computational engine in ROSION is a specific tailored implementation of a column-and-constraint generation algorithm for two-stage robust optimization problems, where a lower and an upper bound on the optimal objective function value are successively calculated until convergence. The lower bound is computed using mixed-integer linear programming and the upper bound via linear programming applied to a sequence of similar problems. ROSION is demonstrated for storage planning on the IEEE 14-bus and 118-bus networks, and the robustness of the designs is validated via Monte Carlo simulation.
Kuenzel S, Kunjumuhhamed LP, Pal BC, et al., 2014, Impact of Wakes on Wind Farm Inertial Response, IEEE Transactions on Sustainable Energy, Vol: 5, Pages: 237-245, ISSN: 1949-3029
Dzafic I, Pal BC, Gilles M, et al., 2014, Generalized π Fortescue Equivalent Admittance Matrix Approach to Power Flow Solution, IEEE Transactions on Power Systems, Vol: 29, Pages: 193-202, ISSN: 0885-8950
This paper develops a generalized admittance matrix approach in Fortescue coordinate system to solve unbalanced/unsymmetrical distribution networks including different number of phases. This generalized Fortescue $pi$ equivalent is defined in this paper for solving the heterogeneous phase, and thus Fortescue, network model. The performance of the approach is demonstrated in different model networks with number of nodes ranging between 168 and 14200. It is found that the current iteration method exploiting the decoupling in admittance matrix in Fortescue coordinate is substantially faster than the typical unbalanced three-phase solution in phase domain. The method has a significant potential for application in real time active power network management.
Agalgaonkar YP, Pal BC, Jabr RA, 2014, Distribution voltage control considering the impact of PV generation on tap changers and autonomous regulators, IEEE Transactions on Power Systems, Vol: 29, Pages: 182-192, ISSN: 0885-8950
The uptake of variable megawatts from photovoltaics (PV) challenges distribution system operation. The primary problem is significant voltage rise in the feeder that forces existing voltage control devices such as on-load tap-changers and line voltage regulators to operate continuously. The consequence is the deterioration of the operating life of the voltage control mechanism. Also, conventional non-coordinated reactive power control can result in the operation of the line regulator at its control limit (runaway condition). This paper proposes an optimal reactive power coordination strategy based on the load and irradiance forecast. The objective is to minimize the number of tap operations so as not to reduce the operating life of the tap control mechanism and avoid runaway. The proposed objective is achieved by coordinating various reactive power control options in the distribution network while satisfying constraints such as maximum power point tracking of PV and voltage limits of the feeder. The option of voltage support from PV plant is also considered. The problem is formulated as constrained optimization and solved through the interior point technique. The effectiveness of the approach is demonstrated in a realistic distribution network model.
Nanchian S, Majumdar A, Pal BC, et al., 2014, Transformer Tap Estimation Using Hybrid Particle Swarm Optimization, IEEE PES General Meeting, Publisher: IEEE, ISSN: 1944-9925
Ablakovic D, Dzafic I, Jabr RA, et al., 2014, Experience in Distribution State Estimation Preparation and Operation in Complex Radial Distribution Networks, IEEE PES General Meeting, Publisher: IEEE, ISSN: 1944-9925
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DZafic I, Halilovic E, Jabr RA, et al., 2014, Influence of Distribution Line Asymmetry on Power Flow Results, IEEE PES General Meeting, Publisher: IEEE, ISSN: 1944-9925
Singh AK, Pal BC, 2014, Decentralized Dynamic State Estimation in Power Systems Using Unscented Transformation, IEEE PES General Meeting, Publisher: IEEE, ISSN: 1944-9925
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- Citations: 1
Agalgaonkar Y, Pal BC, Jabr RA, 2014, Distribution Voltage Control Considering the Impact of PV Generation on Tap Changers and Autonomous Regulators, IEEE PES General Meeting, Publisher: IEEE, ISSN: 1944-9925
Singh AK, Pal BC, 2013, IEEE PES Task Force on Benchmark Systems for Stability Controls - Report on the 68-Bus, 16-Machine, 5-Area System, Publisher: IEEE Power and Energy Society
This report refers to a small-signal stability study carried over the 68-Bus, 16-Machine, 5-Area Sys-tem and validated on a widely known software package: MATLAB-Simulink (ver. 2012b). The 68-bus sys-tem is a reduced order equivalent of the inter-connected New England test system (NETS) and New York power system (NYPS), with five geographical regions out of which NETS and NYPS are represented by a group of generators whereas, the power import from each of the three other neighboring areas are approxi-mated by equivalent generator models. This report has the objective to show how the simulation of this system must be done using MATLAB in order to get results that are comparable (and exhibit a good match with respect to the electromechanical modes) with the ones obtained using other commercial software packages and presented on the PES Task Force website on Benchmark Systems for Stability Controls (http://www.sel.eesc.usp.br/ieee/).
Kuenzel S, Kunjumuhammed LP, Pal BC, 2013, Frequency Response Capability of the GB System in 2030, London, UK, 12th International Workshop on Large-scale Integration of Wind Power into Power Systems as well as on Transmission Networks for Offshore Wind Power Plants, Publisher: Energynautics GmbH
P Kunjumuhammed L, C Pal B, Anaparthi K, et al., 2013, Effect of wind penetration on power system stability
Fabozzi D, Thornhill NF, Pal BC, 2013, Frequency Restoration Reserve Control Scheme with Participation of Industrial Loads, Piscataway, NJ, IEEE PES PowerTech Grenoble 2013, Publisher: IEEE
In order to accommodate larger amounts of renewable energy resources, whose power output is inherently unpredictable, there is an increasing need for frequency control power reserves. Loads are already used to provide replacement reserves, i.e. the slowest kind of reserves, in several power systems. This paper proposes a control scheme for frequency restoration reserves with participation of industrial loads. Frequency restoration reserves are required to change their active power within a time frame of tens of seconds to tens of minutes in response to a regulation signal. Industrial loads in many cases already have the capacity and capability to participate in this service. A mapping of their process constraints to power and energy demand is proposed in order to integrate industrial loads in existing control schemes. The proposed control scheme has been implemented in a 74-bus test system. Dynamic simulations show that industrial loads can be successfully integrated into the power system as frequency restoration reserves.
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