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Proceedings ArticleDOI

Generation dispatch with storage and renewables under Availability Based Tariff

01 Nov 2008-pp 1-6
TL;DR: There are several issues which are unique to the Indian power system namely the frequency linked pricing of energy, asynchronous operation of the grid, blocked governors in state utilities etc, which have a bearing on the generation dispatch which determines the energy availability and cost.
Abstract: There are several issues which are unique to the Indian power system namely the frequency linked pricing of energy, asynchronous operation of the grid, blocked governors in state utilities etc. Each of these has a bearing on the generation dispatch which determines the energy availability and cost. In this work we study the implications of these issues on generation dispatch from first principles. The adverse effects of load prediction error and wind prediction error on dispatch and the utility of storage to mitigate them have been thoroughly analyzed.
Citations
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Journal ArticleDOI
TL;DR: In this paper, a load dispatch model based on ABT is presented, where any unscheduled interchange (UI) from generating units, which helps in maintaining nominal frequency on the grid, invites higher incentives.
Abstract: Grid discipline is very important for smooth and secure operation of any power system. ABT is one such commercial tool which improves the grid discipline by suitably re-dispatching the participating generating units depending upon the frequency of the grid at different intervals. This paper presents a load dispatch model based on ABT, where any unscheduled interchange (UI) from generating units, which helps in maintaining nominal frequency on the grid, invites higher incentives. Besides load variations, the integrated unpredictable renewable sources like the wind and the solar units cause significant UIs and consequently vary the system frequency. The optimum sized pumped storage (PS) unit used in the generation mix compensates these variations, and reduces the UIs and emission. The study has been carried out for restructured power system with significant renewable sources integrated in it. The system frequency is predicted considering the variations in the wind power and in the load demand, and scheduled interchange (SI) power is decided based on the predicted frequency. The grid power schedule decided on the basis of predicted frequency is very useful in minimizing the UI charges. The PS unit improves the frequency profile by suitably adjusting its operation as pump and as generator, which minimizes the cost paid as UI charges. The results of the model proposed have been demonstrated on modified IEEE-14 bus system data.

8 citations

Journal ArticleDOI
15 Jul 2020-Energy
TL;DR: The MG OEM problem is solved considering three different scenarios to scrutinize its robustness in manipulating optimal operating schedules and statistical cost estimates and modified glowworm swarm optimization (MOGSO), a bio-inspired algorithm based on swarm intelligence is proposed to solve optimization functions globally in both deterministic and probabilistic approaches.
Abstract: This article presents a stochastic framework in probabilistic optimal energy management (OEM) of renewable-based microgrid (MG) incorporating uncertainty. OEM of MG is an optimization problem to optimize functional cost of energy associated with distributed generation and responsive loads. Effective coordination between power generation and consumption becomes an essential assignment in MG operation that should be done at a minimum cost and proper scheduling. Renewable energy, load demand and market bids are random which requires a computationally amenable robust uncertainty model to deal with its uncertainty effects. Hence, OEM problem has been formulated using k-point estimation method (k-PEM) based on moments of input random variable (IRV). Inherent randomness associated with renewable energy parameters ascends the MG problem to be stochastic which requires a powerful heuristic tool to obtain optimal operating schedules and cost estimation. Hence, modified glowworm swarm optimization (MOGSO), a bio-inspired algorithm based on swarm intelligence is proposed to solve optimization functions globally in both deterministic and probabilistic approaches. In order to visualize the effectiveness of proposed hybrid PEM-MOGSO method, the MG OEM problem is solved considering three different scenarios to scrutinize its robustness in manipulating optimal operating schedules and statistical cost estimates.

7 citations

01 Jan 2012
TL;DR: In this paper, a real variable genetic algorithm (RGA) method for fixed head hydro-thermal problem is presented for short term hydrothermal scheduling (STHTS) is a daily planning proposition in power system operation.
Abstract: The short term hydrothermal scheduling (STHTS) is a daily planning proposition in power system operation. The main purpose of hydro thermal generation scheduling is to minimize the overall operation cost and to satisfy the given constraints by scheduling optimally the power outputs of all hydro and thermal units under study periods, given electrical load and limited water resource. This paper presents Real Variable Genetic Algorithm method for fixed head hydro-thermal problem. Also, hydro power input-output model with constant head has been developed for Sewa hydro electric power plant by using the curve fitting techniques namely least square method in MATLAB 7.9 version software. The control parameters of genetic algorithm have been optimized for the considered case study.

5 citations

Journal ArticleDOI
TL;DR: A detailed formulation to model energy storage systems (ESS) and renewable sources for power system operation considering 24-hour period is developed and evaluated with two different power systems (i.e. 5-bus and IEEE modified 24-bus systems).
Abstract: The power system operation considering energy storage systems (ESS) and renewable power represents a challenge. In a 24-hour economic dispatch, the generation resources are dispatched to meet demand requirements considering network restrictions. The uncertainty and unpredictability associated with renewable resources and storage systems represents challenges for power system operation due to operational and economical restrictions. This paper develops a detailed formulation to model energy storage systems (ESS) and renewable sources for power system operation considering 24-hour period. The model is formulated and evaluated with two different power systems (i.e. 5-bus and IEEE modified 24-bus systems). Wind availability patterns and scenarios are used to assess the ESS performance under different operational circumstances. With regard to the systems proposed, there are scenarios in order to evaluate ESS performance. In one of them, the increase in capacity did not represent significant savings or performance for the system, while in the other it was quite the opposite especially during peak load periods.

3 citations

Journal Article
TL;DR: Differential evolution (DE) based algorithm is proposed, implemented and compared with real variable genetic algorithm (RVGA) for solving the hydrothermal scheduling problem considering valve point loading for fixed head hydro-thermal problem.
Abstract: The short term hydrothermal scheduling (STHTS), is a daily planning proposition in power system operation. The main purpose of hydro thermal generation scheduling is to minimize the overall operation cost and to satisfy the given constraints by scheduling optimally the power outputs of all hydro and thermal units under study periods, given electrical load and limited water resource. In this paper differential evolution (DE) based algorithm is proposed, implemented and compared with real variable genetic algorithm (RVGA) for solving the hydrothermal scheduling problem considering valve point loading for fixed head hydro-thermal problem. Also, hydro power input-output model with constant head has been developed for Sewa hydro electric power plant by using the curve fitting technique namely least square method. The control parameters of real-variable genetic algorithm and differential evolution have been optimized for the considered case study. From the simulation results, it is found that the DE based approach is able to provide a higher quality solution at a comparatively lesser computational effort.

3 citations

References
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Journal ArticleDOI
TL;DR: In this paper, the impacts of large-scale wind power on system operations from cost, reliability, and environmental perspectives are assessed using a time series of observed and predicted 15-min average wind speeds at foreseen onshore and offshore-wind farm locations.
Abstract: This paper proposes a new simulation method that can fully assess the impacts of large-scale wind power on system operations from cost, reliability, and environmental perspectives. The method uses a time series of observed and predicted 15-min average wind speeds at foreseen onshore- and offshore-wind farm locations. A Unit Commitment and Economic Dispatch (UC-ED) tool is adapted to allow for frequent revisions of conventional generation unit schedules, using information on current wind energy output and forecasts for the next 36 h. This is deemed the most faithful way of simulating actual operations and short-term planning activities for a system with large wind power penetration. The problem formulation includes ramp-rate constraints for generation schedules and for reserve activation, and minimum up-time and down-time of conventional units. Results are shown for a realistic future scenario of the Dutch power system. It is shown that problems such as insufficient regulating and reserve power-which are typically associated with the variability and limited predictability of wind power-can only be assessed in conjunction with the specifics of the conventional generation system that wind power is integrated into. For the thermal system with a large share of combined heat and power (CHP) investigated here, wind power forecasting does not provide significant benefits for optimal unit commitment and dispatch. Minimum load problems do occur, which result in wasted wind in amounts increasing with the wind power installed

643 citations


"Generation dispatch with storage an..." refers background in this paper

  • ...The effect of prediction errors [6] and the possible role of storage [7] in an ABT based network have been analyzed....

    [...]

Journal ArticleDOI
TL;DR: In this article, the authors considered the impact of uncertain wind forecasts on the value of stored energy (such as pumped hydro) in a future U.K. system, where wind supplies over 20% of the energy.
Abstract: This paper considers the impact of uncertain wind forecasts on the value of stored energy (such as pumped hydro) in a future U.K. system, where wind supplies over 20% of the energy. Providing more of the increased requirement for reserves from standing reserve sources could increase system operation efficiency, enhance wind power absorption, achieve fuel cost savings, and reduce CO2 emissions. Generally, storage-based standing reserve's value is driven by the amount of installed wind and by generation system flexibility. Benefits are more significant in systems with low generation flexibility and with large installed wind capacity. Storage is uniquely able to stock up generated excesses during high-wind/low-demand periods, and subsequently discharge this energy as needed. When storage is combined with standing reserve provided from conventional generation (e.g., open-cycle gas turbines), it is valuable in servicing the highly frequent smaller imbalances

302 citations


"Generation dispatch with storage an..." refers background in this paper

  • ...The effect of prediction errors [6] and the possible role of storage [7] in an ABT based network have been analyzed....

    [...]

Proceedings ArticleDOI
10 Jun 2004
TL;DR: This paper discusses an unconventional concept- tariff linked to frequency which has been introduced in India at the inter-state level through the three-part tariff for central generating stations, the so called availability based tariff (ABT).
Abstract: This paper discusses an unconventional concept- tariff linked to frequency. This new concept has been introduced in India at the inter-state level, starting from mid 2002, through the three-part tariff for central generating stations, the so called availability based tariff (ABT). In this scheme overdrawals are costly when the grid is short on generation, and are cheap when the grid has surplus generating capacity. Similarly any oversupply is paid for at a high rate when frequency is below 50.0 Hz and at a low rate when the frequency is above 50.0 Hz. Underdrawal and undersupply also get the same treatment.

37 citations


"Generation dispatch with storage an..." refers background in this paper

  • ...The present electricity policy in India called the Availability Based Tariff (ABT) [2, 3 ], has a price component which is linked to frequency....

    [...]

Proceedings ArticleDOI
12 Jun 2005
TL;DR: The commercial mechanism, availability based tariff (ABT), adopted by India has facilitated seamless integration on commercial front to a good extent and the guiding principles for such standardization are reported in this paper.
Abstract: That regional interconnections can benefit interconnected grids is accepted by the decision makers owing to optimal utilization of resources, diversity of load patterns, increased security and improved system performance. However, there are "opportunities and threats" depending on how commercial, operational and security issues are tackled. The threats stem from potential seaming problems in the integration and lack of adequate defense mechanisms. In India, five large sized regional grids operate and these are interconnected either synchronously or asynchronously. The operating strategies for interconnections have evolved through trial operations on exiting system which are covered in this paper. The paper overviews the salient features of all the regional interconnections in India. The commercial mechanism, availability based tariff (ABT), adopted by India has facilitated seamless integration on commercial front to a good extent as described in this paper. ABT links part of tariff with a universally available signal of system frequency. From experience gained over last few years, the operational and security issues have been discussed. With open access in operation, the interconnecting corridors have to play a significant role in the operation of the interconnected system. The need for evolving standards for the integrated operation became evident from the experience. The guiding principles for such standardization are also reported in this paper.

17 citations


"Generation dispatch with storage an..." refers background in this paper

  • ...Due to operational reasons the Indian power system is demarcated into five regions- Northern, Southern, Western, Eastern and North Eastern [1]....

    [...]

Proceedings Article
01 Dec 2007
TL;DR: It is shown that pumped storage on daily schedule has a beneficial impact on economics but increase emissions, and optimized generation scheduling with due consideration to emission factors of thermal plants is required.
Abstract: Availability based tariff (ABT) is a commercial mechanism launched in India since 2003 to improve grid discipline in an inherently energy deficient system In this structure cost of unscheduled electricity purchased by state electricity boards (SEBs) from central generating stations (CGS) is inversely proportional to grid frequency The quantitative impact of pumped storage (PS) on frequency profile is analyzed by formulating the problem as a constrained linear programming one We initially show that pumped storage can improve the operating frequency profile and economics of a region But while dimensioning the storage emissions need to be addressed and hence, three different objectives are posed- optimal generation scheduling with conventional least cost strategy, optimal generation scheduling with least emission strategy, optimal generation scheduling with combined economic and emission dispatch strategy Utilizing the TamilNadu grid as a case study, it is shown that pumped storage on daily schedule has a beneficial impact on economics but increase emissions Hence optimized generation scheduling with due consideration to emission factors of thermal plants is required

4 citations


"Generation dispatch with storage an..." refers background in this paper

  • ...The total thermal, hydro and wind availability and entitlements for the sample days are obtained from [8]. The unit details are available in [ 9 ]....

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