光伏新能源并网系统的区间优化

摘要

新能源的大规模并网,势必增加电力系统运行参数的诸多不确定性,实现新能源并网系统稳定运行的关键:建立光伏发电系统并网的合理优化模型;提供其稳定运行的电压极限区间和系统合理的"承载容量",因此,提出将区间优化算法应用于光伏并网系统运行参数的优化.以光伏发电并网节点电源容量为目标函数,配电网节点电压和支路功率特性作为约束条件,建立光伏发电并网系统区间优化的非线性模型;利用区间可能度和区间序关系实现目标函数和约束条件的确定性模型转化,实现光伏并网节点电压波动最小和全网有功损耗最小为两层嵌套的区间优化函数,以光伏发电并网注入有功容量和并网节点电压的区间边界函数作为约束条件,将光伏发电系统的有功功率不等式约束和光伏发电系统并网调节问题结合建立多节点光伏发电系统并网的优化模型,实现鲁棒性的最优求解.利用IEEE33节点配电系统算例仿真,光伏单点接入末端的分叉支路,对配电网末端节点电压提升效果最好;系统末端节点电压提升3.3%~11.8%,末端节点电压下边界优化区间[9.8277,9.8367],实现节点电压下边界由-5%精确至-1.72%;多节点光伏接入并网系统,其有功功率损耗优化区间[131.6576,143.4365],比较光伏接入前降低63.8%~66.8%;首端功率优化区间[30.446,354.59],实现首端有功功率最大调峰354.59kW,为光伏发电并网系统的可靠性运行提供保证.该方法具备高精度求解和快速收敛的特点,适用于改善农村配电网末端电压过低的状况,同时该光伏并网的区间优化方法提供了光伏并网配置方案,为未来电力系统配电网重构提供重要的理论依据.%New energ y acce ss t he power distribution system on the large scale, increases the uncertainties of the operating parameters of power system. There are two aspects to the key issue of achieving the new energy grid system stable operation:establishing reasonable optimization model of photovoltaic power generation grid-connected system, and providing the voltage limit interval and system rational "carrying capacity" based on stable operation conditions. Therefore, we put forward the application of the interval optimization algorithm for realizing the operation parameter optimization of PV grid-connected system. The power source capacity of the photovoltaic power grid node was used as the objective function, and the distribution network node voltage and branch power characteristics as the constraint conditions, a nonlinear model of the interval optimization was created in regard to the photovoltaic power generation system. The deterministic model transformation of objective function and constraint condition using the interval possibility and interval order relationship were completed. Two nested interval optimization functions were established in order to achieve the minimum node voltage fluctuations and the minimum network active power loss. The interval boundary function of the active capacity and the node voltage as the constraint condition. It sets up the optimization model of multi-node PV grid-connected system was used to combine the active power inequality constraints and the regulation of PV grid-connected. The optimal solution of robustness was obtained. The simulation of IEEE 33 node power distribution system had the best effect to improve the voltage of the end node of the distribution network. The voltage of the end node was enhanced by 3.3% - 11.8%, with the optimal range of the end node voltage lower boundary [9.8277, 9.8367], the accuracy of node voltage lower boundary being from -5% to -1.72% the optimal range of active power loss being [131.6576, 143.4365] with the reduction of the active power loss by 63.8% - 66.8% compared with no PV grid-connected system. The first-end power optimization interval was [30.446, 354.59], achieving the active power maximum adjustment peak 354.59kW, which provided the reliability of the operation for the photovoltaic power grid-connected system. The method had the characteristics of high precision and fast convergence suitable for improving the condition of the voltage at the end of the rural distribution network. The PV grid-connected configuration scheme could be provided by utilizing the interval optimization method, which could provide an important theoretical basis for the future power distribution network reconstruction.