Publications
254 results found
P Kunjumuhammed L, C Pal B, F Thornhill N, 2013, A Test System Model for Stability Studies of UK Power Grid, IEEE PES PowerTech Grenoble 2013
Dzafic I, Gilles M, Jabr RA, et al., 2013, Real Time Estimation of Loads in Radial and Unsymmetrical Three-Phase Distribution Networks, IEEE Transactions on Power Systems, Vol: 28, Pages: 4839-4848, ISSN: 0885-8950
This paper presents a load estimator for large scale asymmetric distribution networks. It is based on iterating between 1) a weighted least squares (WLS) estimator that attempts to adjust the forecasted load group values to the telemetered measurements and 2) a three-phase load flow employing the Fortescue transformation. The WLS estimation phase explicitly handles Y- and $Delta$-connected unbalanced loads and area losses; it can also identify bad measurements based on the estimated load scaling factors. Numerical results show that the proposed load estimator is superior to conventional load allocation based on current balancing, and that its performance is commensurate with the requirements of real-time applications on unsymmetrical radial distribution networks having up to one million nodes.
Ariff MAM, Pal BC, 2013, Coherency Identification in Interconnected Power Systems - An Independent Component Analysis Approach, IEEE Transactions on Power Systems, Vol: 28, Pages: 1747-1756, ISSN: 0885-8950
This paper presents a novel approach to the coherency identification technique in interconnected power system using independent component analysis (ICA). The ICA is applied to the generator speed and bus angle data to identify the coherent areas of the system. The results of the application of ICA using simulated data from 16-machine 68-bus system model and on data gathered through U.K. University-based Wide-Area Measurement System are presented. The approach is able to identify the cluster of generators and buses following a disturbance in the system. It is also demonstrated that the approach is robust in the presence of noise in measured signal, which is an important factor to be considered for assessing the effectiveness of any measurement-based technique.
Fabozzi D, Thornhill N, Pal BC, 2013, Power System Control
Summary of InventionIn accordance with an aspect of the invention there is provided a method for allocating a plurality of power reserves to deliver power to a power network to meet a power reserve requirement for balancing a frequency of the power network. The method comprises obtaining, for a plurality of power reserves of a power network, power reserve flexibility characteristics associated with each power reserve. The method further comprises obtaining, for the plurality of power reserves, an indexing value associated with the delivery of power by each of the power reserves. The method further comprises determining a power reserve requirement associated with the power network. The method further comprises assigning one or more of the plurality of power reserves to deliver power to the power network, the plurality of power reserves assigned in accordance with the power reserve flexibility characteristics associated with each of the power reserves, the indexing value associated with each of the power reserves, and the power reserve requirement associated with the power network. The power reserve flexibility characteristics may be indicative of power deliverable to the power network by the respective power reserve with respect to time. The power reserve flexibility characteristics may include characteristics of positive and/or negative power reserve flexibility.The power reserve flexibility characteristics may include one or more of a maximum deliverable power, a period of time to provide the maximum deliverable power from receipt of an instruction for power delivery, a minimum duration for sustaining the maximum deliverable power and a period of time to reduce power delivery from the maximum deliverable power to a minimum deliverable power.The assigning of one or more of the plurality of power reserves may further comprise selecting one or more of the plurality power reserves to provide the power reserve requirement in order of the indexing value associated with t
Sarkar S, Dutta D, Samanta SK, et al., 2013, Oxidative inhibition of Hsp90 disrupts the super-chaperone complex and attenuates pancreatic adenocarcinoma in vitro and in vivo, INTERNATIONAL JOURNAL OF CANCER, Vol: 132, Pages: 695-706, ISSN: 0020-7136
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- Citations: 56
Ariff MAM, Pal BC, 2013, Coherency Identification in Interconnected Power System—An Independent Component Analysis Approach, IEEE Transactions on Power Systems, Vol: 28, Pages: 1747-1756
Simfukwe D, Pal B, 2013, Robust and Low Order Power Oscillation Damper Design Through Polynomial Control, General Meeting of the IEEE-Power-and-Energy-Society (PES), Publisher: IEEE, ISSN: 1944-9925
Barocio E, Pal BC, Fabozzi D, et al., 2013, Detection and visualization of power system disturbances using principal component analysis, IREP Symposium: Bulk Power System Dynamics and Control - IX Optimization, Security and Control of the Emerging Power Grid, IREP 2013
In this paper, a multivariate statistical projection method based on Principal Component Analysis (PCA) is proposed for detecting and extracting unusual or anomalous events from wide-area monitoring data. The method combines PCA with statistical test to detect and analyze anomalous dynamic events from measured data. Simulations based on a transient stability model of the New England Test System are used to demonstrate the ability of the method to detect and extract system events from wide-area data. © 2013 IEEE.
Thornhill NF, Fabozzi D, Pal BC, 2013, Monitoring and management of power transmission dynamics in an industrial smart grid, IEEE PES PowerTech Grenoble 2013
This article is a position paper whose purpose is to give the context for presentations in a special session at PowerTech 2013. The special session is being proposed by the EU FP7 Real-Smart Consortium, a Marie Curie Industry-Academic Pathways and Partnerships project. The paper gives an overview of topics on modeling, monitoring and management of power transmission dynamics with participation from large industrial loads. © 2013 IEEE.
Chattopadhyay SK, Chakraborty C, Sinha AK, et al., 2013, Asymmetric Multilevel Inverter with Quasi-Linear Power Distribution Ratio for Grid Connected Photovoltaic Converters, IEEE International Symposium on Industrial Electronics (ISIE), Publisher: IEEE, ISSN: 2163-5137
Kuenzel S, Kunjumuhammed LP, Pal BC, et al., 2012, Wind Power Plants Inertial Response Capability Considering Wake Effect, 11th International Workshop on Large-Scale Integration of Wind Power into Power Systems as well as on Transmission Networks for Offshore Wind Power Plants, Lisbon
Manitsas E, Singh R, Pal BC, et al., 2012, Distribution System State Estimation using an Artificial Neural Network Approach for Pseudo Measurement Modeling, IEEE Transactions on Power Systems, Vol: 27, Pages: 1888-1896-1896, ISSN: 0885-8950
This paper presents an alternative approach topseudo measurement modeling in the context of distributionsystem state estimation (DSSE). In the proposed approach pseudomeasurements are generated from a few real measurements usingartificial neural networks (ANNs) in conjunction with typicalload profiles. The error associated with the generated pseudomeasurements is made suitable for use in the weighted leastsquares (WLS) state estimation by decomposition into severalcomponents through the Gaussian mixture model (GMM). Theeffect of ANN-based pseudo measurement modeling on thequality of state estimation is demonstrated on a 95-bus sectionof the U.K. generic distribution system (UKGDS) model
Jabr RA, Singh R, Pal BC, 2012, Minimum Loss Network Reconfiguration Using Mixed-Integer Convex Programming, IEEE Transactions on Power Systems, Vol: 27, Pages: 1106-1115, ISSN: 0885-8950
This paper proposes a mixed-integer conic programmingformulation for the minimum loss distribution network reconfigurationproblem. This formulation has two features: first,it employs a convex representation of the network model whichis based on the conic quadratic format of the power flow equationsand second, it optimizes the exact value of the network losses.The use of a convex model in terms of the continuous variables isparticularly important because it ensures that an optimal solutionobtained by a branch-and-cut algorithm for mixed-integer conicprogramming is global. In addition, good quality solutions with arelaxed optimality gap can be very efficiently obtained. A polyhedralapproximation which is amenable to solution via more widelyavailable mixed-integer linear programming software is also presented.Numerical results on practical test networks including distributedgeneration show that mixed-integer convex optimization is an effective tool for network reconfiguration.
Jabr RA, Martins N, Pal BC, et al., 2012, Contingency Constrained VAr Planning Using Penalty Successive Conic Programming, IEEE Transactions on Power Systems, Vol: 1, Pages: 545-553, ISSN: 0885-8950
This paper presents a new method for VAr planning under multiple operating scenarios, optimizing sizes and locations of new reactive compensation equipment to ensure that both the system voltage profile and voltage stability requirements are met. The approach is based on ${mbi L}_{1}$-norm regularization for finding a solution with minimum VAr installation sites and on the ${mbi L}_{2}$-norm penalty function for satisfying the multiple state constraints. The ${mbi L}_{2}$-norm penalty function is exact in the sense that a finite penalty parameter is required to establish equivalence with the VAr planning problem, thus avoiding numerical ill-conditioning. The solution is obtained from a successive conic programming algorithm which makes use of adaptive trust-region control. The results of the new method are compared with those of an optimal power flow-based program for VAr planning.
Bell KWR, Fenton B, Griffiths H, et al., 2012, Attracting Graduates to Power Engineering in the U.K.: Successful University and Industry Collaboration, IEEE Transactions on Power Systems, Vol: 1, Pages: 450-457, ISSN: 0885-8950
The power industry in many parts of the industrialized world faces major challenges over the next two decades to renew ageing networks, accommodate new generation, especially renewables, and make grid operation “smarter”. This requires increasing numbers of professionals, but in many places, the industry faces great losses in personnel and experience as senior engineers retire. As a consequence, the industry needs to recruit a new generation of well-qualified electrical engineering graduates. This paper describes one particular initiative to attract school leavers into engineering and electric power engineering in particular: the U.K.'s “Power Academy”. The main features of the scheme and its success to date are described along with the new challenges and various issues that remain to be addressed. These include the need for “engineering leadership” and career progression for technical specialists. It is argued that companies' continued investment in schemes like the Power Academy is essential to meet the challenges faced by the power industry and to ensure a healthy future supply of professional engineers
Caro E, Singh R, Pal BC, et al., 2012, An Incremental PMU Placement Method for Power System State Estimation, IET Generation Transmission and Distribution, Vol: 6, Pages: 922-929
This study focuses on the selection of the most effective location of phasor measurement units (PMUs) in the network for the purpose of state estimation. The reduction in the error of the estimated states, that is, the quality improvement of the estimate, is the objective used to select the most appropriate allocation of PMUs. The concept of participation of various states into the uncertainty of the error is applied to identify the most important states influencing the estimated errors. Unlike other methods, the proposed technique considers all the elements of the state error covariance matrix and therefore addresses the impact of correlations between the errors. The effectiveness of the method has been demonstrated on the standard IEEE 14-bus and IEEE 57-bus system models. The comparison of performance with other existing measurement placement techniques targeting the same objective reflects the effectiveness of the participation factor-based approach.
Kunjumuhhamed LP, Singh R, Pal BC, 2012, Robust Signal Selection for Damping Inter-area Oscillations, IET Generation Transmission and Distribution, Vol: 6, Pages: 404-416, ISSN: 1751-8687
This study reports an approach of selecting effective feedback signal to damp out electromechanical oscillations in the power system under unpredictable supply and demand situation. The idea of minimum variance of the modal residue has been utilised to select a signal which is very effective over a large number of operating conditions. A minimal variation of residue results in minimal deviation in damping performance from the desired level. The effectiveness of the method is demonstrated in a 16-machine, 68-bus NETS-NYPS test system and 46-machine, 190-bus practical Mexican interconnected system models.
Simfukwe D, Pal BC, Jabr RA, et al., 2012, Robust and Low Order Design of FACTS and Power System Stabilizers for Oscillations Damping, IET Generation Transmission and Distribution, Vol: 6, Pages: 445-452, ISSN: 1751-8687
The study presents a method for the coordinated design of low-order robust controllers for stabilising power system oscillations. The design uses conic programming to shift under-damped or unstable modes into a region of sufficient damping of the complex plane and involves two stages. The first stage is a phase compensation design that accounts for multiple operating conditions with flexible AC transmission systems (FACTS) and power system stabilisers (PSS), unlike our earlier approach involving PSS only. The second stage is gain tuning. This is done effectively in a coordinated way using conic programming. An example demonstrates the method's ability to design coordinated FACTS and PSS controllers resulting in damping oscillations over all given operating conditions of the power system with very simple and low-order control structure.
Chattopadhyay SK, Chakraborty C, Pal BC, 2012, A Hybrid Multilevel Inverter Topology with Third Harmonic Injection for Grid Connected Photovoltaic Central Inverters, 21st IEEE International Symposium on Industrial Electronics (ISIE), Publisher: IEEE, Pages: 1736-1741, ISSN: 2163-5137
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- Citations: 15
Chattopadhyay SK, Chakraborty C, Pal BC, 2012, Cascaded H-Bridge & Neutral Point Clamped Hybrid Asymmetric Multilevel Inverter Topology for Grid Interactive Transformerless Photovoltaic Power Plant, 38th Annual Conference on IEEE-Industrial-Electronics-Society (IECON ), Publisher: IEEE, Pages: 5074-5079, ISSN: 1553-572X
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- Citations: 9
Thambirajah J, Thornhill NF, Pal BC, 2011, A Multivariate Approach Towards Inter-Area Oscillation Damping Estimation Under Ambient Conditions Via Independent Component Analysis And Random Decrement, IEEE Transactions on Power Systems, Vol: 26, Pages: 315-322, ISSN: 0885-8950
This paper presents a novel approach to the monitoring of interarea oscillation frequency and damping using multivariate analysis techniques. A two-step method is presented 1) independent component analysis for the detection of interarea modes and estimation of their frequencies and 2) random decrement for the estimation of mode damping. The method is applied to real measurements taken in Finland within the Nordic Power System to estimate the critical interarea mode frequency and damping in the system.
Singh R, Manitsas E, Pal BC, et al., 2011, A Recursive Bayesian Approach for Identification of Network Configuration Changes in Distribution System State Estimation, General Meeting of the IEEE-Power-and-Energy-Society (PES), Publisher: IEEE, ISSN: 1944-9925
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- Citations: 1
Jukka T, Thambirajah J, Larsson M, et al., 2011, Comparison of Three Electromechanical Oscillation Damping Estimation Methods, IEEE Transactions on Power Systems, Vol: 26, Pages: 2398-2407, ISSN: 0885-8950
This paper describes three data driven methods to monitor electromechanical oscillations in interconnected power system operation. The objective is to compare and contrast the performance of the methods. The accuracy of damping ratio and frequency of oscillations are the measures of the performance of the algorithms. The advantages and disadvantages of various techniques and their limitations to measurement noise have been considered while assessing performance. The target frequency and damping are computed using the Nordic power system simulation model.
Jabr R, Pal B, Martins N, 2011, A Sequential Conic Programming Approach for the Coordinated and Robust Design of Power System Stabilizers, General Meeting of the IEEE-Power-and-Energy-Society (PES), Publisher: IEEE, ISSN: 1944-9925
Singh R, Pal BC, Jabr RA, et al., 2011, Meter Placement for Distribution System State Estimation: An Ordinal Optimization Approach, IEEE Transactions on Power Systems, Vol: 26, Pages: 2328-2335, ISSN: 0885-8950
This paper addresses the problem of meter placement for distribution system state estimation (DSSE). The approach taken is to seek a set of meter locations that minimizes the probability that the peak value of the relative errors in voltage magnitudes and angle estimates across the network exceeds a specified threshold. The proposed technique is based on ordinal optimization and employs exact calculations of the probabilities involved, rather than estimates of these probabilities as used in our earlier work. The use of ordinal optimization leads to a decrease in computational effort without compromising the quality of the solution. The benefits of the approach in terms of reduced estimation errors is illustrated by simulations involving a 95-bus UKGDS distribution network model.
Barocio E, Pal BC, Messina AR, 2011, Real-Time Monitoring as Enabler for Smart Transmission Grids, General Meeting of the IEEE-Power-and-Energy-Society (PES), Publisher: IEEE, ISSN: 1944-9925
Jabr RA, Pal BC, Martins N, et al., 2010, Robust and coordinated tuning of power system stabiliser gains using sequential linear programming, IET Generation, Transmission and Distribution, Vol: 4, Pages: 893-904, ISSN: 1751-8687
This study presents a linear programming (LP)-based multivariable root locus following technique for coordinating the gain settings of power system stabilisers (PSSs). The stabiliser robustness is accounted for in the design problem by simultaneously considering the state-space representations and multivariable root loci corresponding to different operating scenarios. The proposed technique computes a curve in the PSS gain parameter space such that when the PSS gains move along this curve to their optimal values, the branches of the corresponding multivariable root loci terminate at satisfactory points in the complex plane. The curve in the gain parameter space is computed via a linear program that successively minimises the Euclidean distance between the unsatisfactory and satisfactory eigenvalue locations. The design method is demonstrated on a 39-bus test system with 14 operating scenarios. A comparison is carried out between the coordination results of two PSS structures, one involving two phase-lead blocks and the other comprised of two phase-lead blocks and a phase-lag block.
Jabr RA, Pal BC, Martins N, 2010, A Sequential Conic Programming Approach for the Coordinated and Robust Design of Power System Stabilizers, IEEE Transactions on Power Systems, Vol: 25, Pages: 1627-1637
This paper shows that conic programming is an effective tool to solve robust power system stabilizer (PSS) design problems, namely coordinated gain tuning and coordinated phase and gain tuning. Design robustness is achieved by simultaneously considering several operating scenarios. The method is implemented through a sequence of conic programming runs that define a multivariable root locus along which the eigenvalues move. Specifically, the eigenvalues corresponding to the unstable and poorly damped modes are moved to a conic sector in the left half of the s-plane, whereas the eigenvalues corresponding to the well damped modes are constrained to stay within the boundaries of this conic sector. At each step of the solution, the PSS design parameters are restricted in a trust-region such that the computation of the eigenvalue shift based on the residue method holds valid. The proposed method is demonstrated on a 68-bus test system with nine different operating conditions. Comparisons are carried out between conic programming implementations for PSS coordinated gain tuning and for simultaneous tuning of gain and phase characteristics
Singh R, Manitsas E, Pal BC, et al., 2010, A Recursive Bayesian Approach for Identification of Network Configuration Changes in Distribution System State Estimation, IEEE Transactions on Power Systems, Vol: 25, Pages: 1329-1336
This paper deals with the identification of network configuration changes in distribution system state estimation (DSSE). The models of critical network configurations are stored in the form of a model bank. A recursive Bayesian approach which utilizes the output of the state estimation function of each model in the bank is used to identify the correct configuration of the network. The concept is demonstrated on a part of the U.K. Generic Distribution System (UKGDS) model.
Singh R, Pal BC, Jabr RA, 2010, Distribution System State Estimation Through Gaussian Mixture Model of the Load as Pseudo Measurement, IET Generation, Transmission and Distribution, Vol: 4, Pages: 50-59
This study presents an approach to utilise the loads as pseudo-measurements for the purpose of distribution system state estimation (DSSE). The load probability density function (pdf) in the distribution network shows a number of variations at different nodes and cannot be represented by any specific distribution. The approach presented in this study represents all the load pdfs through the Gaussian mixture model (GMM). The expectation maximisation (EM) algorithm is used to obtain the parameters of the mixture components. The standard weighted least squares (WLS) algorithm utilises these load models as pseudomeasurements. The effectiveness of WLS is assessed through some statistical measures such as bias, consistency and quality of the estimates in a 95-bus generic distribution network model.
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