Sanjoy Roy

• Professor at Indian Institute of Technology Ropar

As a support to performance assessment of deepwater wave energy converters, this work quantifies susceptibility of output power to short duration variations, independent of source wave statistics. Introduced as 𝝇-metrics, the quantified measures may be a basis for technology comparisons, with possible convergence to a choice for implementation. The...

In the wake of a proposed installation of two-body floating heave buoy wave energy convertor (WEC) off coast of Vizhinjam in peninsular India, this paper analyses functional estimates of short duration mean power generation and associated variability at a site in deepwater vicinity of the port town. The work is motivated by two aspects that are of...

With deepwater wave power generation being seriously considered as a viable option across the marine vicinity of India, seasonal disparity of mean power as well as short duration power variability are of interest in the context of site and technology selection. Past experience with an onshore wave power installation in the region has not been altog...

With power from integrated vRES added to electricity generated by conventional sources across a commitment interval, unexpected real-time changes in demand and generation may contribute substantial overheads to the optimal cost of energy (CoE). This paper presents analytical formulations and illustrative examples to focus on a significant fraction...

The power output by a small hydropower generation unit (SHP) is conventionally estimated as a product of the net head, admitted flow, and a typical value of efficiency. In case of run of river (RoR) units however, sub-daily variability of stream flow together with consequent variation of efficiency make the conventional estimate open to errors. Th...

[ For follow up, please refer to the additional "Comment" submitted by author on RG. ] ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ As a critical component for evaluation of out...

A constraint to represent maximum likelihood of occurrence for coexistent variable demand and variable generation is proposed for inclusion in the conventional static load dispatch. The constraint allows direct representation of cross-correlations between variable power levels, which makes the dispatch appropriate for scenarios with high penetratio...

Photovoltaic (PV) power generation units located in tropical or equatorial sites frequently experience low-lying, dense cloud cover; and are thereby exposed to rapid real time changes in irradiance. Commonly referred to as cloud transients, the changes lead to short duration power variations and substantial reduction of output from individual units...

A scatter of operating points is commonly observed over time whenever a pitch angle controlled (PAC) wind energy conversion system (WECS) operates in source wind susceptible to short duration variations caused by turbulence and gusts. A suitable interpretation of the distributed operating points can be useful in the context of real-time performance...

Integration of non-dispatchable renewable power sources within a utility service area warrants possible revision of default cost optima obtained by conventional economic dispatch (ED). Uncertain shifts in the minimum cost may be expected due to variation of demand and generation, and convenient prior estimates of such changes would undoubtedly be o...

The statistics of low level scattered cloud cover (cumulus or strato-cumulus types), is evolved to formulate analytical expressions for short duration mean output power and its variability, as well as power change distribution, at the output of photovoltaic generating stations. The proposed expressions are used to obtain statistical estimates of th...

Short duration wind variations affect real time performance of active pitch-regulated wind turbines in two ways as evident from reported experimental and empirical studies. First the mean output power, which may be referred to as the short duration output power, differs significantly from the corresponding zero-turbulence value obtained with ideal...

The inexact power output from a pitch angle-controlled (PAC) horizontal-axis turbine, as influenced by short duration wind variations like turbulence and gusts, has been the subject of well-documented experimental and empirical studies. In this paper, an analytical interpretation of the phenomena is presented under assumption of two-parameter Weibu...

The distorted output of a pitch angle controlled (PAC) horizontal axis turbine, as influenced by short duration wind variations like turbulence and gusts, is analyzed under the assumption of two-parameter Weibull statistics. The well accepted concept of turbulence intensity is used as a parametric measure of short duration wind variations. Analytic...

Randomness of wind speed around a short-duration-stable mean value is commonly referred to as short duration wind variation. This paper investigates the effect of substantial wind-based capacity inclusion on optimal load dispatch, with the source wind susceptible to short duration variations. Analytical formulation of the economic load dispatch (EL...

If proposed wind park configurations are planned through a globally coordinated approach across a utility service area, then electricity can be fed into the grid with substantial cost advantages. This paper shows that by four important measures, such optimal multiunit plans are sensitive to wind regimes presented by candidate sites to available mak...

The characteristic low mechanical inertia of isolated (grid-independent) wind-diesel generating units makes them significantly susceptible to time-varying components of wind speed, such as gusting and periodic ramping. With the electrical frequency maintained nearly constant by the diesel/alternator part, wind dynamics are typically reflected in te...

If wind park configurations are globally coordinated across the service area of a power utility, then electricity can be generated for the grid with substantial cost advantages. Based on this premise, the paper introduces a model by which large scale assessment of grid connected wind based power generation may be undertaken for a utility service ar...

The fundamental formulation, analysis and sample simulation studies reported show how the linear power system stabiliser (PSS) can be evolved so as to accommodate more than one identical power generating unit operating at a common busbar. The presentation augments the more conventional approach by which the PSS is formulated for a single-machine-in...

A new multiunit optimization algorithm is formulated to plan participation by photovoltaic sources with significant penetration in utility generation. The focus is on the minimization of the overall levelized cost of energy, with constraints on demand, capacity as decided by penetration, efficiency levels, and various cost components. Collector are...

This work presents an approach by which multiple microscale hydro generating units can be planned over a catchment area consisting of several potential installation sites so as to extract the maximum possible energy per-unit investment cost. With a pre-decided overall charge rate, this would, in turn, determine the annual payback of levelized insta...

This paper presents long-term production costing as an important decision tool that can be used to assess entry of exogenous players within an otherwise centrally planned, natural monopolistic market. The ex-monopolist emerges as the dominant participant of the restructured market, and continues to play a decisive role in price determination. In do...

R.C. Bansal, et al. comment on the paper by S. Roy (see ibid., vol.17, p.124-9, 2002). They suggest that additional data for wind energy conversion systems and site conditions may be considered. S. Roy replies to the comments.

This paper presents two market dependent optimization algorithms that can be used to plan wind energy conversion system (WECS) installations simultaneously over several sites of interest to a utility, within the scope of (1) available WECS models, (2) power demand of the utility, and (3) wind characteristics at each site; both (2) and (3) being var...

This paper presents two market dependent optimization algorithms that can be used to plan wind energy conversion system (WVECS) installations simultaneously over several sites of interest to a utility, within the scope of (a) available WECS models, (b) power demand of the utility, and (c) wind characteristics at each site; both (b) and (c) being va...

In comparison to conventional industrial cogeneration plants, the closed loop combined cycle cogeneration (CLCC) system has the advantage that it needs virtually no enhancement in steam handling capability of the existing plant, both in terms of steam pressure and volume flow rates. An optimal design procedure is introduced in the paper for configu...

In comparison to conventional industrial cogeneration plants, the closed loop combined cycle cogeneration (CLCC) system has the advantage that it needs virtually no enhancement in steam handling capability of the existing plant, both in terms of steam pressure as well as volume flow rates. An optimal design procedure is introduced in this paper for...

In systems where production of a commodity or service is accompanied by simultaneous generation of detriments, reduction of the latter usually implies increase in production cost. This leaves considerable scope for sustainable decisions regarding the extent to which control of detriments can be done in a cost effective manner. One example of such a...

This paper introduces a new small perturbation model for the well known “generator/infinite bus” system, that includes explicit representation of amortisseur windings. The major points of difference between this model and the conventional Heffron-Phillips small perturbation model are discussed by a comparison of synchronising and damping torque coe...

Traditionally, steam-based cogeneration systems have been added to industrial applications as topping cycle or bottoming cycle configurations. Such systems frequently require that pressure or steam flow handling capacity of one or more existing steam headers be enhanced. The aim of this work is to suggest a new type of cogeneration system configura...

This paper attempts a novel formulation for the steady-state output DC voltage of a three-phase alternator fed HVDC converter, expressed as a function of the output DC current of the configuration. The formulation includes a detailed representation of alternator flux-linkages, and involves relevant self and mutual inductance parameters as well as t...

This paper introduces an optimisation model that may be used for planning wind turbine installations over a global energy scenario. The model follows from the observation that, in most practical cases, installations may have to be made under space constraints, and that this may limit the overall energy output per unit land area. In such cases, it m...

This paper describes a method to recommend allocation of generating units, with a view to achieve cost-effective control of particulate and gaseous emissions over an energy scenario. Definition of relative cost and relative emission, with respect to corresponding base-case values, allows one to develop a model that describes cost and emission aspec...

Export Date: 16 May 2012, Source: Scopus

A computationally powerful digital signal processor (DSP)-based implementation of adaptive speed control algorithms for a diesel-driven electric generating unit is described in this paper. The complexity of the algorithm and the short control interval required for this application necessitated the use of a DSP. Hardware and software have been desig...

This paper introduces a two-stage optimization process that can be used to determine local and inter-utility tariffs for a scenario. The scenario can include several power utilities with local demand of electrical energy. It can also be associated with a central authority that (a) co-ordinates the energy pricing, and (b) owns some generating units...

Self-tuning adaptive control algorithms, that employ explicit dead-time identification techniques, have been discussed in the literature vis-a-vis the diesel-driven power prime-mover. Such algorithms are numerically intensive owing to the complicated identification algorithms. This paper discusses the implementation of the above mentioned algorithm...

Scheduling methods, which reduce undesirable emissions from fossil-fuel generating units, has been a matter of considerable interest to power utilities. This paper introduces the idea that overall emission-reduction for a system can be achieved by optimizing the emissions at a few most emissive units, instead of doing so at all units. Such an appro...

An adaptive speed control scheme for diesel prime movers is presented. Diesel prime movers are characterized by nonlinear, time-varying parameters including a nonlinear input dead-time variation that introduces an unknown delay between the injection of fuel and the production of engine torque. Such plants are difficult to control by conventional pr...

A method of modeling, involving approximation of dead-times, is presented for diesel driven power prime-movers. The resulting predictive adaptive control scheme is compared to a conventional PI scheme on the basis of common disturbances encountered by a practical prime-mover. It is found that the adaptive scheme achieves significant improvement des...

Of the variety of identification and adaptive control methods that are applied to plants with dead-time, most differ in the way the dead-time is modelled. Common approaches include approximating the delay effect by several poles, or by all-pass filters. In this paper an attempt is made to derive some sufficient conditions for all-pole delay models...

The adaptive control scheme introduced by S. Roy et al. (1991) for naturally aspirated diesel prime-movers has been applied to turbocharged generation plants. The performance has been studied in comparison to that of a fixed PI (proportional plus integral) controller. It is seen that since the nonlinear effect of air dynamics now affects the dynami...

The performance of an incremental Clarke-Gawthrop adaptive control scheme, suitable for a diesel-engine prime mover, is described. The controller uses a predictor that is derived from explicit estimates of the plant deadtime and time constants. Its performance under speed reference changes and load disturbances has been compared to that of a fixed,...

In the design of identification algorithms, the dead-time is usually modelled by some form of a polynomial function that adequately approximates the dead-time behaviour over relevant frequency bands. The application of all-zero models for approximation of plant dead-times is discussed. A gain-error criterion is established for a general model, wher...

Of the variety of identification and adaptive control methods that are applied to plants with dead-time, most differ in the way the dead-time is modelled. Common approaches include approximating the delay effect by several poles, or by all-pass filters. In this paper an attempt is made to derive some sufficient conditions for all-pole delay models...

The recursive least-squares estimation technique is extended for application to systems with small but unknown dead-time delays. This problem is studied with particular reference to when the diesel engine is used as a prime-mover, in which case the dead-time leads to a significant variation in dynamic performance. In practice, least-squares estimat...

An adaptive control scheme, based on a low-order model of a diesel driven power plant, is used for the speed control of the prime-mover. By using an explicit identification of the delay, it is shown that a low-order identification model can prove to be adequate even when the actual plant delay is time-varying. It is shown both by the frequency resp...

Adaptive control of a power prime-mover requires effective modeling and identification techniques that have good disturbance rejection properties. Existing methods tend to avoid explicit modeling of input dead-time due to resulting computational complexity. Two different approaches of modeling the diesel power prime-mover are presented. The predict...