考虑不确定性的电压暂降不兼容度和影响度评价指标及方法

Uncertainty Description and Assessment of Incompatibility & Influence Index for Voltage Sags

随着敏感性用电设备的大量使用,电压暂降已经成为最重要的电能质量问题之一。合理、准确评估电压暂降的严重程度和电压暂降对敏感设备造成的影响,不仅能够用来衡量系统供电质量的优劣,而且也是电力市场环境下电能按质论价的前提。为合理、准确地评估电压暂降的严重性,将不确定性表示方法应用于电压暂降严重性评估中。采用云模型描述电压暂降幅值特征和设备电压耐受能力;将正态云模型的期望曲线作为隶属函数,采用模糊安全事件隶属函数方法描述设备受电压暂降影响可能出现的故障状态。建立了一种用云模型表示和计算的电压暂降不兼容度和影响度指标,以反映电压暂降的严重性和对设备造成的影响程度。用配电网电压暂降仿真模型进行仿真分析,给出了评估结果,验证了方法的可行性和合理性。

With the extensive use of sensitive electrical equipment, voltage sag has become one of the most important power quality problems. Evaluating the severity and the influence on sensitive equipment of voltage sag reasonably and accurately can not only measure the quality of power system supply, but also provide basis for fixing prices according to the quality in the electric power market. In order to assess the severity and the influence of voltage sag reasonably and accurately in sensitive equipment, some uncertainty representations are applied in voltage sag severity assessment. Cloud model is used to describe voltage sagJ s features and voltage tolerance of sensitive equipment, and fuzzy security incidents membership function is used to describe the state of equipment failures subjected to voltage sag. Incompatibility index and influence index are presented by cloud model to reflect and calculate the severity and the influence of voltage sag in sensitive equipment. Distribution network voltage sag simulation examples show that the presented method is feasible and reasonable.