在缺失部分概率分布参数的场合,通过概率-区间混合型不确定性潮流计算,能够直观地获取潮流分布及其区间信息,但现有方法依赖于抽样与数值计算,效率不高。为此,文章提出一种概率嵌入型混合不确定性潮流计算方法(probabilistic embedding mixed uncertainty power flow calculation method,PEPF),无需进行复杂采样,且可在系统常规工况下高效、准确求解潮流。该方法针对分布式电源的随机不确定性与负荷功率的区间不确定性,首先定义一种以输入变量概率作为嵌入因子的混合不确定性解析模型,将潮流计算由单个运行状态拓展至连续状态空间。此后,构建系统输入与潮流计算的级联解析化模型,采用线性递归求解状态量的各阶幂级数系数,获取状态量关于输入概率的解析多项式。最后,采集稀疏且高覆盖性的概率样点,即可快速代值计算潮流解的概率分布边界。基于IEEE30与IEEE141标准节点系统验证了所提方法的准确性与有效性。
Abstract
In scenarios where certain probability distribution parameters are absent
the probability-interval hybrid uncertainty power flow calculation can directly obtain the power flow distribution and its associated interval bounds. However
the existing methods rely on sampling and numerical computation
which leads to inefficiency. To address this issue
a probabilistic embedding mixed uncertainty power flow (PEPF) calculation method is proposed
which can efficiently and accurately solve power flows under normal operating conditions without complex sampling. The proposed method targets the stochastic uncertainty of distributed generation and the interval uncertainty of load power. First
it defines a mixed uncertainty analytical model with input variable probabilities as embedded factors
extending power flow calculations from a single operating state to a continuous state space. Subsequently
a cascaded analytical model linking system inputs and power flow calculations is constructed. A linear recursive approach is employed to determine the power series coefficients of state variables
thereby obtaining analytical polynomial expressions of these variables to input probabilities. Finally
by collecting sparse yet highly representative probability sample points
the boundaries of power flow solution distributions can be efficiently determined through direct substitution. The accuracy and effectiveness of the proposed method are verified by using the IEEE 30-bus system and IEEE 141-bus system standard node systems.