计及时空相关性的分布式风电接入配电网风险评估

随着分布式电源的大量接入,为研究分布式风电的相关性对配电网风险的影响,提出了一种计及时空相关性的分布式风电接入配电网风险评估方法。首先,考虑风电出力在不同季节的时空相关性,基于Copula函数和马尔科夫模型建立风电出力两阶段四季场景生成模型;其次,为提高风险评估的效率,基于红黑树结构建立动态故障集,通过查找、存储已抽样状态序列及其评估结果,避免同一状态反复调用程序计算潮流;最后,在IEEE 33节点配电网系统中计算配电网过电压、低电压、线路过载和失负荷运行风险指标,并基于层次分析法建立综合运行风险指标,合理全面地评估了强相关性风电接入配电网带来的风险,验证了所提模型和方法的有效性和准确性。

Operation Risk Evaluation on Distributed Wind Power Connected to Distribution Network Considering Temporal-Spatial Correlation

With the massive access of distributed power generation, in order to study the impact of the correlation of distributed wind power on the risk assessment of the distribution network, a risk assessment method for distributed power generations connected to distribution network considering temporal-spatial correlation is proposed. Firstly, considering the temporal-spatial correlation of wind power generators in different seasons, a two-stage wind power scenario generation model considering temporal-spatial correlation in different seasons is established on the basis of Copula function and Markov chain model. Secondly, in order to improve the computational efficiency of risk assessment, the dynamic fault set is established on the basis of the red-black tree structure. By searching and storing the sampled state sequence and its evaluation results, it avoids repeatedly calling the optimal power flow in the same state, and improves the speed of state evaluation. Finally, the operational risk indices such as over-voltage, low-voltage, line overload and loss of load are calculated in IEEE 33-bus distribution network system, and the comprehensive operational risk indices are established on the basis of analytic hierarchy process. The risk caused by strongly correlated wind power connected to distribution network is reasonably and comprehensively evaluated, and the effectiveness and accuracy of the proposed model and method are verified.