配电网状态估计的全局灵敏度分析及应用

在配电网状态估计中,量测装置配置不齐全,通常引入伪量测来满足系统的可观性要求。考虑到量测数据有一定的误差以及伪量测与真实值之间可能存在偏差,配电网状态估计的量测和伪量测存在不确定性,这会影响配电网状态估计的准确性。文中提出了配电网状态估计的全局灵敏度分析方法,辨识影响状态估计精度的关键(伪)量测不确定性因素及其位置;利用稀疏多项式混沌展开计算全局灵敏度指标,以提高全局灵敏度分析的计算效率;建立了基于不确定性因素重要性排序的量测装置布点方法。采用IEEE 33节点配电网进行仿真,通过与常用方法进行比较,验证了所提方法的有效性。该方法克服了传统状态估计灵敏度分析方法的不足,能有效评估(伪)量测不确定性因素的交互作用对状态估计的影响;此外,基于全局灵敏度分析的量测装置布点方法能显著提高配电网状态估计精度。

Global Sensitivity Analysis on State Estimation of Distribution Network and Its Application

In distribution network state estimation, measurement devices are limited and network observability is not achieved unless pseudo measurements are used. Considering the measurement errors and the deviations between the pseudo measurements and the actual values, the (pseudo-) measurements have uncertainties in distribution network state estimation, which will affect the performance of state estimation. The global sensitivity analysis method of the distribution network state estimation is proposed, to identify the critical (pseudo-) measurement uncertainties and their locations, which have an impact on the accuracy of state estimation. Based on the sparse polynomial chaos expansion, the global sensitivity indices are calculated to improve the computational efficiency of the global sensitivity analysis. And the metering placement method based on the importance ranking of uncertain parameters is provided. The proposed approach is tested on the IEEE 33-bus distribution system. Compared with the common methods, the accuracy and efficiency of the proposed method are verified. This method overcomes the shortcomings of the traditional state estimation sensitivity analysis. It evaluates the influence of the correlation of (pseudo-) measurement uncertainties on state estimation. The metering placement method based on the global sensitivity analysis is able to significantly improve the accuracy of distribution network state estimation.