Congestion management for generation scheduling in a deregulated Chinese power system
28 Jan 2001-Vol. 3, pp 1262-1265
TL;DR: In this paper, a congestion management algorithm is developed to alleviate the congestion caused by allocated generation and to be economic at the same time, which is the main topic of this paper.
Abstract: Deregulation and market competition has been introduced into the Chinese utility industry. In order to alleviate the congestion caused by allocated generation and to be economic at the same time, a congestion management algorithm is developed, which is the main topic of this paper. The proposed algorithm utilizes the fast linear programming algorithm and considers the nonlinear cost of generators. When the system congestion cannot be alleviated only by adjusting the unit output, the proposed algorithm calculates an index of commitment change for each unit to re-commit units. Based on this algorithm, a security-integrated closed-loop generation scheduling is realized. Tests on the deregulated power system of Liaoning Province in China are also reported in this paper, and the result verifies the validity and efficiency of the presented algorithm.
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TL;DR: In this paper, an improved differential evolution based approach is proposed to ease congestion in transmission lines by generator rescheduling and installation of new wind farms, where an enhanced mutation operator is introduced to improve the performance of the differential evolution algorithm.
Abstract: Congestion management is imperative for reliable and secure system operation in restructured power systems. Since the installation of wind farms at proper locations offers the possibility of congestion relief, this paper investigates congestion management in power systems with specific consideration of wind energy sources. The optimal location of a wind farm is determined by the Bus Sensitivity Factor and the Wind Availability Factor. Differential Evolution is a population-based heuristics algorithm used for solving non-linear optimization problems. We propose an Improved Differential Evolution based approach to ease congestion in transmission lines by generator rescheduling and installation of new wind farms. In this approach, an enhanced mutation operator is introduced to improve the performance of the Differential Evolution algorithm. A standard IEEE-30 bus system is used to evaluate the proposed algorithm under critical line outages. The simulation results show that the proposed approach is more effective than other approaches.
41 citations
05 Dec 2005
TL;DR: In this paper, the impact of wind generation on the generation schedule, particularly the overall fuel cost, amount of emissions and system security, was evaluated based on the IEEE30 bus test system, with conventional and wind generation plant over a period of one week.
Abstract: In recent years, environmental concerns have significantly increased the pressure for cleaner and more efficient generation of electricity. In the UK and some European countries, there are requirements to produce a certain amount of electricity from renewable generation. Wind power is expected to contribute significantly to the renewable energy targets owing to advancements in wind technologies, falling capital costs, abundance of the free resource and commercial viability. However, wind is intermittent and unpredictable, posing serious threats to power system security. Despite the changes in generation mix and the market operation of power systems, priority remains on maintaining system security and minimising operation costs. This poses a fundamental challenge to the traditional generation scheduling methodologies that have worked well in hydrothermal dominated and vertically integrated environments. This paper evaluates the impact of wind generation on the generation schedule, particularly the overall fuel cost, amount of emissions and system security. The analysis is based on the IEEE30 bus test system, with conventional and wind generation plant over a period of one week. Results show that spinning reserve and production costs increase with increasing amounts of intermittent generation and emissions are reduced accordingly. System security initially improves but deteriorates with significant wind power penetration
36 citations
Cites background from "Congestion management for generatio..."
...Methods exist in literature for incorporating security aspects due to congestion [1], [2], [3] unit ramping and thermal stress [4], [5] and voltage/reactive...
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TL;DR: An improved optimal congestion cost model is built by introducing the congestion factor in dealing with the cases: opening the generator side and load side simultaneously and the designed algorithm is safe and easy to implement.
Abstract: This paper investigates the cost control problem of congestion management model in the real-time power systems. An improved optimal congestion cost model is built by introducing the congestion factor in dealing with the cases: opening the generator side and load side simultaneously. The problem of real-time congestion management is transformed to a nonlinear programming problem. While the transmission congestion is maximum, the adjustment cost is minimum based on the ant colony algorithm, and the global optimal solu-tion is obtained. Simulation results show that the improved optimal model can obviously reduce the adjust-ment cost and the designed algorithm is safe and easy to implement.
17 citations
Cites background from "Congestion management for generatio..."
...Reference [12] designed a relatively simple regulation for blocking costs against the optimization model of transmission congestion management....
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27 Mar 2009
TL;DR: In this paper, a hybrid method for ramp rate constrained unit commitment (RUC) problem is presented, which combines Lagrangian relaxation principle with evolutionary programming and quadratic programming (LREQP) for short-term thermal unit commitment.
Abstract: This paper proposes an approach which combines Lagrangian relaxation principle with evolutionary programming and quadratic programming (LREQP) for short-term thermal unit commitment. Unit commitment is a complex combinatorial optimization problem which is difficult to be solved for large- scale power systems. This paper presents a hybrid method for ramp rate constrained unit commitment (RUC) problem. Hybrid LREQP minimizes the total supply cost subject to the power balance, generation ramp limit constraints, on/off line minimum level constraints, minimum up and new down time constraints and generator operating constraints. The proposed solution method solves unit commitment problem with two coordination procedures. In the first procedure, an evolutionary programming algorithm is used to improve a solution obtained by the Lagrangian relaxation method: Lagrangian relaxation gives the starting point for a evolutionary programming procedure. In the second procedure, economic dispatch (ED) by quadratic programming (QP) is performed 24 hours to simultaneously dispatch output subject to all constraints and unit decommitment is carried out. Hybrid LREQP is tested on the 26 unit IEEE reliability test system. The proposed algorithm takes the advantages of both methods and therefore it can search a better solution within short computation time.
16 citations
10 Jun 2004
TL;DR: In this article, an improved Lagrangian relaxation (ILR) algorithm is proposed for centralized dispatch of transmission constrained generation scheduling (TCGS) problem in a centralized electricity market to minimize the consumer payment rather than the total supply cost subject to the power balance, spinning reserve, transmission lines, and generator operating constraints.
Abstract: This paper proposes an improved Lagrangian relaxation (ILR) for centralized dispatch of transmission constrained generation scheduling (TCGS) problem in a centralized electricity market. ILR minimizes the consumer payment rather than the total supply cost subject to the power balance, spinning reserve, transmission lines, and generator operating constraints. ILR algorithm is improved by new initialization of Lagrangian multipliers and adaptive adjustment of Lagrangian multipliers. If congestion exists, the alleviating congestion index is proposed for congestion management. Finally, the unit decommitment is performed to prevent excessive spinning reserve. The ILR for TCGS is tested on the 4 unit and the IEEE 24 bus reliability test systems. The proposed system electricity price including the uniform distributed side payment could ensure generator revenue adequacy leading to a lower consumer payment than system marginal price based on uniformly fixed cost amortized allocation.
7 citations
References
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TL;DR: A linear programming method for security dispatch and emergency control calculations on large power systems is presented, which works directly with the normal power-system variables and limits, and incorporates the usual sparse matrix techniques.
Abstract: A linear programming (LP) method for security dispatch and emergency control calculations on large power systems is presented. The method is reliable, fast, flexible, easy to program, and requires little computer storage. It works directly with the normal power-system variables and limits, and incorporates the usual sparse matrix techniques. An important feature of the method is that it handles multi-segment generator cost curves neatly and efficiently.
396 citations