• Title, Summary, Keyword: Rescheduling

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Rescheduling on Parallel Machines with Compressible Processing Times (작업시간이 압축 가능한 경우 병렬기계의 재일정계획)

  • Kim, Suhwan
    • Journal of the Society of Korea Industrial and Systems Engineering
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    • v.38 no.2
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    • pp.47-55
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    • 2015
  • This paper deals with rescheduling on unrelated parallel-machines with compressible processing times, assuming that the arrival of a set of new jobs triggers rescheduling. It formulates this rescheduling problem as an assignment problem with a side constraint and proposes a heuristic to solve it. Computational tests evaluate the efficacy of the heuristic.

Generation Rescheduling Based on Energy Margin Sensitivity for Transient Stability Enhancement

  • Kim, Kyu-Ho;Rhee, Sang-Bong;Hwang, Kab-Ju;Song, Kyung-Bin;Lee, Kwang Y.
    • Journal of Electrical Engineering and Technology
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    • v.11 no.1
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    • pp.20-28
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    • 2016
  • This paper presents a generation rescheduling method for the enhancement of transient stability in power systems. The priority and the candidate generators for rescheduling are calculated by using the energy margin sensitivity. The generation rescheduling formulates the Lagrangian function with the fuel cost and emission such as NOx and SOx from power plants. The generation rescheduling searches for the solution that minimizes the Lagrangian function by using the Newton’s approach. While the Pareto optimum in the fuel cost and emission minimization has a drawback of finding a number of non-dominated solutions, the proposed approach can explore the non-inferior solutions of the multiobjective optimization problem more efficiently. The method proposed is applied to a 4-machine 6-bus system to demonstrate its effectiveness.

A Study on the Rescheduling of Generation Considering Contingency in Power System with Wind Farms (풍력발전단지가 연계된 전력계통에서 상정고장을 고려한 발전력 재조정에 관한 연구)

  • Choi, Soo-Hyun;Kim, Kyu-Ho
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.66 no.2
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    • pp.255-260
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    • 2017
  • This paper studies on effective rescheduling of generation when the single line contingency has occurred in power system with wind farm. The suggested method is formulated to minimize the rescheduling cost of conventional and wind generators to alleviate congestion. The generator rescheduling method has been used with incorporation of wind farms in the power system. Since all sensitivity is different about congestion line, Line Outage Distribution Factor(LODF) and Generator Sensitivity Factor(GSF) is used to alleviate congestion. The formulation have been proccessed using linear programming(LP) optimization techniques to alleviate transmission congestion. The effectiveness of the proposed rescheduling of generation method has been analyzed on revised IEEE 30-bus systems.

A Study on the Development of Rescheduling Procedure for Shipbuilding Master Production Schedule (조선 기준일정계획을 위한 재계획 절차의 개발)

  • Park, Ju-Chull;Hwang, Ha-Yong
    • IE interfaces
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    • v.11 no.3
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    • pp.129-141
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    • 1998
  • In this paper, a rescheduling procedure is developed for shipbuilding master production schedule. Shipyard initially develops backward production schedules for the entire shipbuilding process, and then refines the schedule by stage. The rescheduling procedure of this paper tries to resolve the schedule discrepancies between the outdoor backward schedule and the refined indoor schedule. Through the proposed rescheduling procedure, outdoor schedule can be successfully adjusted using buffer days and duration reduction. An Object-oriented program is also developed to automate the procedure. We can observe the improvement on productivity and quality of rescheduling works from the application of the developed procedure.

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Task Rescheduling Using a Coordinator in a Structural Decentralized Control of Supervisory Control Systems

  • Lee, Sang-Heon;Kim, Ill-Soo;Kai C. Wong
    • International Journal of Precision Engineering and Manufacturing
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    • v.5 no.2
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    • pp.22-31
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    • 2004
  • A problem of task rescheduling using a coordinator in a structural decentralized control of supervisory control theory is formulated. we consider that the overall system is divided into a number of local systems. Using an example of a chemical batch reaction process, it has shown that after local supervisors have been established for a given task, a coordinator can be used to solve some rescheduling problems among local plants for new or modified tasks. The coordination system models the interactions of local plants, and is consisting of only the shared events of local plants, so simpler to synthesize. A coordinator is designed based on the specifications given for the coordination system. Under the 'structural' conditions developed in this paper, the combined concurrent actions of the coordinator with the existing local supervisors will achieve the rescheduling requirements. Again since the conditions are structural (not specification-dependent), once the coordination architecture has been established, it can be used for a number of different tasks without further verifications.

No Tardiness Rescheduling with Order Disruptions

  • Yang, Jaehwan
    • Industrial Engineering and Management Systems
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    • v.12 no.1
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    • pp.51-62
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    • 2013
  • This paper considers a single machine rescheduling problem whose original (efficiency related) objective is minimizing makespan. We assume that disruptions such as order cancelations and newly arrived orders occur after the initial scheduling, and we reschedule this disrupted schedule with the objective of minimizing a disruption related objective while preserving the original objective. The disruption related objective measures the impact of the disruptions as difference of completion times in the remaining (uncanceled) jobs before and after the disruptions. The artificial due dates for the remaining jobs are set to completion times in the original schedule while newly arrived jobs do not have due dates. Then, the objective of the rescheduling is minimizing the maximum earliness without tardiness. In order to preserve the optimality of the original objective, we assume that no-idle time and no tardiness are allowed while rescheduling. We first define this new problem and prove that the general version of the problem is unary NP-complete. Then, we develop three simple but intuitive heuristics. For each of the three heuristics, we find a tight bound on the measure called modified z-approximation ratio. The best theoretical bound is found to be 0.5 - ${\varepsilon}$ for some ${\varepsilon}$ > 0, and it implies that the solution value of the best heuristic is at most around a half of the worst possible solution value. Finally, we empirically evaluate the heuristics and demonstrate that the two best heuristics perform much better than the other one.

Optimal Power Flow based on Priority of Generation Rescheduling (발전력재배분의 priority를 이용한 최적전력조류)

  • Kim, Kyu-Ho;Kim, Soo-Nam;Rhee, Sang-Bong;Lee, Sang-Keun;Song, Kyung-Bin
    • Proceedings of the KIEE Conference
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    • pp.412-413
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    • 2011
  • This paper presents a new generation rescheduling approach for preventive control of power systems, which can optimally reallocate power generations for unstable contingencies. The transient stability constraints used in the optimal rescheduling model are described by energy margin sensitivity. Especially the energy margin sensitivity is evaluated for change with respect to generation. For a given contingency, the energy margin is computed and the respective sensitivities are also computed.

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Fuzzy PSO Congestion Management using Sensitivity-Based Optimal Active Power Rescheduling of Generators

  • Venkaiah, Ch;Vinod Kumar, D M
    • Journal of Electrical Engineering and Technology
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    • v.6 no.1
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    • pp.32-41
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    • 2011
  • This paper presents a new method of Fuzzy Particle Swarm Optimization (FPSO)-based Congestion Management (CM) by optimal rescheduling of active powers of generators. In the proposed method, generators are selected based on their sensitivity to the congested line for efficient utilization. The task of optimally rescheduling the active powers of the participating generators to reduce congestion in the transmission line is attempted by FPSO, Fitness Distance Ratio PSO (FDR-PSO), and conventional PSO. The FPSO and FDR-PSO algorithms are tested on the IEEE 30-bus and Practical Indian 75-bus systems, after which the results are compared with conventional PSO to determine the effectiveness of CM. Compared with FDR-PSO and PSO, FPSO can better perform the optimal rescheduling of generators to relieve congestion in the transmission line.

Comparative Study of Two Congestion Management Methods for the Restructured Power Systems

  • Manikandan, B.V.;Raja, S. Charles;Venkatesh, P.;Mandala, Manasarani
    • Journal of Electrical Engineering and Technology
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    • v.6 no.3
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    • pp.302-310
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    • 2011
  • Congestion management is one of the most challenging tasks of a system operator to ensure the operation of transmission system within operating limits. In this paper, cluster/zone method and relative electrical distance (RED) method for congestion management are compared based on the considered parameters. In the cluster/zone method, rescheduling of generation is based on user impact on congestion through the use of transmission congestion distribution factors. In the RED method, the desired proportions of generations for the desired overload relieving are obtained. Even after generation rescheduling, if congestion exists, load curtailment option is also introduced. Rescheduling cost, system cost, losses, and voltage stability parameter are also calculated and compared for the above two methods of congestion management. The results are illustrated on sample 6-bus, IEEE 30-bus, and Indian utility 69-bus systems.

Optimal Congestion Management Based on Sensitivity in Power System with Wind Farms (민감도를 이용하여 풍력단지가 연계된 송전계통의 최적혼잡처리)

  • Choi, Soo-Hyun;Kim, Kyu-Ho
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.65 no.12
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    • pp.1965-1970
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    • 2016
  • This paper studies generator rescheduling technique for congestion management in power system with wind farms. The proposed technique is formulated to minimize the rescheduling cost of conventional and wind generators to alleviate congestion subject to operational line overloading. The generator rescheduling method has been used with incorporation of wind farms in the power system. The locations of wind farms are selected based upon power transfer distribution factor (PTDF). Because all generators in the system do not need to participate in congestion management, the rescheduling has been done by generator selection based on the proposed generator sensitivity factor (GSF). The selected generators have been rescheduled using linear programming(LP) optimization techniques to alleviate transmission congestion. The effectiveness of the proposed methodology has been analyzed on IEEE 14-bus systems.