考虑网内与网外购电计划差异的月度最优外购电模型

计及市场电价、水电生产、负荷需求的不确定性因素,结合外购电计划给网内系统带来的峰荷与谷荷状态可能都不满足调峰要求,以及局部线路和潮流断面的传输功率可能越限的问题,建立了省级电网月度最优外购电模型。模型的目标函数为全网购电费用及半绝对离差风险价值二者均最低,约束条件重点为月峰荷、谷荷2种负荷状态下的系统调峰约束和电网支路及断面直流潮流安全约束。采用非序贯蒙特卡洛模拟法模拟模型中的不确定性因素,结合线性加权和法与线性规划法求解购电组合中的多目标线性规划问题。以重庆电网为例,仿真分析了低谷调峰、网络安全约束及节点负荷电力不确定性对外购电计划的影响,验证了所建模型的有效性和实用性。

An Optimal Monthly Power Purchasing Model Considering Differences Between Internal and External Grid

By taking into account the uncertainties of market prices,hydroelectricity production and load demand and the possible failure of both the peak-and/or valley-load duration in the intragrid system to meet the requirement for peak regulation as well as the possible overload of branches or sections due to external power purchase,a monthly optimal power purchasing model for the provincial grid is developed.The objective is to minimize the power purchasing cost and semi-absolute deviation risk measurement,while the constraint is mainly the system peak regulating constraint and grid branch and section DC flow security constraint in the monthly peak load state and valley load state.The multi-objective linear programming in the power purchasing portfolio is solved by simulating the uncertainty factors in the model using the non-sequential Monte Carlo method in conjunction with the linear weighted sum method and linear programming.Finally,Chongqing power grid is used as an example to test the validity and practicality of the proposed model and analyze the influence of peak regulation,security constraints and bus load power uncertain factors on the optimal power purchasing scheme.