基于仿射最小路法的含分布式电源配电网可靠性分析

大规模风电和光伏发电以分布式电源形式接入电力系统,提高了配电网可靠性评估的复杂度。针对分布式电源输出功率的随机性问题,建立了基于马尔可夫过程的发电机多容量状态模型以模拟出力波动。在此基础上,为克服区间最小路法过于保守的不足,提出了可以有效缩减区间范围的仿射最小路法,该算法既考虑了配电网元件及负荷的原始参数不确定性,也计及了不确定变量之间的相关性。以IEEE-RBTS母线6配电系统为例,分析瞬时故障对配电网可靠性的影响,并对所提出的模型和算法的合理性进行验证。结果表明,仿射最小路法相比于区间最小路法,在可靠性指标计算方面具有更高的精准度,并且在系统不确定性越大时区间缩减效果越明显,为实际工程中的可靠性评估及系统规划设计提供了有力依据。

Reliability Analysis of Distribution Network with Distributed Generators Based on Affine Minimal Path Method

Wind power and photovoltaic generation in large scale is connected to the distribution network in the form of distributed power supply, which increases the complexity in the reliability assessment of the distribution network. A multi-capacity state model of the generator based on the Markov process is developed to simulate the output fluctuation in face of the randomness of the distributed power output. In order to avoid the over-estimation problem of the interval minimum method, an affine minimal path method is proposed to effectively reduce the range of calculation results. This algorithm considers not only the original parameter uncertainties for components and the load points in the distribution network, but also the correlation between the uncertain variables. With the IEEE-RBTS BUS 6 power distribution system as an example, the rationality of the proposed model and algorithm is verified, and the influence of transient fault on the reliability evaluation of the system is analyzed. The result shows that the affine minimal path method has higher accuracy than the interval-minimum method in calculating the reliability index. The greater the uncertainty of the system is, the more obvious will the effect of interval reduction appear, which provides a reliable basis for reliability evaluation and system planning and design in actual engineering.