基于区间数逼近的微网电压暂降风险评估

Risk Assessment of Micro-Grid Voltage Sag Based on an Approximation Method of Interval Numbers

当前微网的概念已逐渐深入到现代电网运行中,其中电能质量问题具有很强的随机性和不确定性。将风险评估理论引入到微网电能质量分析中,用区间数估计理论替代传统的定值估计方法,建立了基于区间数逼近的微网电压暂降风险评估模型。该模型还考虑了微网中各类分布式电源的权重优化问题,对合理配置分布式电源具有一定指导作用。算例结果表明,该方法可以较好地反映微网中电压暂降的随机性,并引入模糊理论对其风险值综合评估,能准确反映事实,客观科学,具有一定的推广和应用价值。

At present,the concept of micro-grid has been gradually introduced into the operation of modern power grids, but the power quality of micro-grid has a strong randomness and uncertainty.This paper introduces the theory of risk assessment into power quality analysis of micro-grid,and using interval numbers estimation theory to substitute the traditional setting estimation method,and based on approximation method of interval numbers this paper proposes a voltage sag risk assessment model for micro-grid.The model also takes into account weight optimization of various types of micro-distributed power sources, which can play a guiding role in the rational allocation of distributed power.The simulation results show that the method can well reflect the stochastic voltage sag in micro-grid,and the introduction of fuzzy theory on its comprehensive risk assessment can accurately reflect the facts.It is objective and scientific, thus has a certain value for the promotion and application.