From the optimization point of view, an optimum solution of the Unit commitment problem with reliability constraints can be achieved when all constraints are simultaneously satisfied rather than sequentially or separately satisfying them. Therefore, the reliability constraints need to be appropriately formulated in terms of the conventional Unit commitment variables. In this paper, the reliability-constrained Unit commitment problem is formulated in a mixed-integer program format. Both the Unit commitment risk and the response risk are taken into account as the probabilistic criteria of the operating reserve requirement. In addition to spinning reserve of generating Units, interruptible load is also included as a part of operating reserve. The numerical studies using IEEE-RTS indicate the effectiveness of the proposed formulation. The obtained results are presented and the implementation issues are discussed. Two sensitivity analyses are also fulfilled to illustrate the effects of generating Unit failure rates and interruption time of interruptible load.

Given the importance of Unit commitment risk (UCR) assessment in determining the probability of meeting load demand in the ahead short-term operation period, in this paper, a new analytical model for UCR assessment is presented. In the proposed model to consider the impact of wind power participation in the entire short-term period of operation of the system, using the developed risk area concept, a new model for UCR assessment is presented. Furthermore, uncertainties of wind power and load demand are considered simultaneously. Unlike the models presented in previous research for UCR assessment, which consider the share of wind power in the last period of operation, the proposed model for UCR assessment considers the share of wind power in all periods of operation. The proposed model was tested and evaluated on the RBTS system with a wind farm. Moreover, the results obtained from the simulation were reported. According to the results, in all cases, the value of UCR in the proposed model is lower than the modified PGM (M-PGM) method. The effectiveness of this innovative approach in evaluating the UCR of the power system despite wind power and load uncertainties was confirmed based on the results.

This paper aims to study the effect of the hourly demand response (DR) on security-constraint Unit commitment (SCUC) problem with considering economic and security objectives. The demand side participation can solve some of the electricity market problems. Here, DR is take into consideration as one of the demand side management (DSM) parts. The DR is consist of fixed and responsive loads. The fixed loads satisfy in any circumstance and responsive loads can curtail or shift to other operating hours. The combination of SCUC with DR is a complex and the mixed integer non-linear problem. The bender’ s decomposition is used as an optimization technique for solve this problem. This technique solves the problem by decompose it into master and sub problems. One of the effective of this manner is reducing the processing time. The performance and effectiveness of the proposed method are demonstrated on 6-, 24-and 118-bus test systems.

As renewable energy increasingly penetrates into power grid systems, new challenges arise for system operators to keep the systems reliable under uncertain circumstances, while ensuring high utilization of renewable energy. This paper presents Unit commitment (UC) which takes into account the volatility of wind power generation. The UC problem is solved with the forecasted intermittent wind power generation and possible scenarios are simulated for representing the wind power volatility. The iterative process between the commitment problem and the economic dispatch (ED) problem will continue until we find the optimum mode of committing the Units. Furthermore we have considered a hydro pump storage (HPS) Unit to be a part of operating system in order to mitigating wind power forecasting errors and peak shaving. Numerical simulations indicate the effectiveness of the proposed UC for managing the security of power system operation by taking into account the intermittency and volatility of wind power generation.

This paper proposes a novel technique for solving generation scheduling and ramp rate constrained Unit commitment. A modified objective function associated with a new start-up cost term is introduced in this paper. The proposed method is used to solve generating scheduling problem satisfying SRR, minimum up and down time as well as ramp rate constraints. Two case studies are conducted to implement and show the effectiveness of the proposed method. One is a conventional 10-Unit system and its multiples while the other is a 26-Unit system with 24-h scheduling horizon. A comparison between the results of the proposed technique with those of some methods demonstrates a significant improvement.