Studies On Unit Commitment Considering Spinning Reserve Optimization

Spinning reserve (SR) is one of the most important resources used by system operators to maintain system security and improve operational reliability, which is also a decision-making problem coordinating system operation security and economy. With the development of electrical industry and introduction of market mechanism, constantly increasing uncertainties during system operation process have highlighted the importance of SR. It's obviously meaningful for this thesis to choose this subject for deep research.Based on previous achievement at home and abroad, the thesis focuses on uncertainties in system operation process and introduces probability optimization theory to unit commitment and SR optimization. To make unit commitment and SR optimization more intelligent and reasonable, the thesis strives to achieve coordination of system operation security and economy in unit commitment, simultaneous optimization of generation and SR requirement, as well as shedding off the drawback of human decision.Firstly, this thesis introduces a practical mixed-integer linear model of unit commitment and its sloving strategy. The nonlinear objective fuction and constraints of unit commitment is transformed into linear form, and therefore the linear form can be sloved by large-scale commercial optimization software. This method can conveniently make extension of unit commitment, and make researchers consantrated on unit commitment model but never mind the sloving algorithm.Then, based on the research on relationship between system operation risk and SR requirement, a unit commitment model considering expected customer interruption cost (ECOST) is proposed. The proposed model which adds ECOST into unit commitment objective function, can automatically determine optimal SR capacity by making compromise between system operation cost and ECOST. System expected energy not supplied (EENS) is expressed and simplified by unit commitment variables when assess ECOST, so as to achieve simultaneous optimization of generation and SR requirement in unit commitment.Based on above, a probabilistic unit commitment model based on multi-scenario technique is proposed. In the proposed model, system operation process is represented by several scenarios. ECOST under every scenario is considered in unit commitment, system cost and operation risk under every scenario is coordinated by each scenario occurrence probability. Network security constraints and readjustments of unit commitment after contingencies are included in the model, so as to guarantee the decision plain doesn't violate transmission limits of lines in all scenarios.At last, probabilistic unit commitment model based on multi-scenario technique is applied to power system with wind power generation. By probabilistic expression of wind power forecast error, probabilistic unit commitment model of power system with wind power generation based on multi-scenario technique is established, and SR requirement according to wind power fluctuation is automatically optimized. Network security constraints are included in the model to consider its impact on unit commitment and SR optimization. From the view of wind power economic value analysis, a new method to determine optimal wind power penetration in each bus is presented based on the proposed unit commitment model. The method which aims at minimizing system expected cost can determine optimal economic wind power penetration in each bus and do have significant meaning in scheduling and planning of wind power.