电压暂降的计算及故障点电压暂降系数确定

由于电力系统中新型电力电子设备的广泛应用,电压暂降已逐渐成为影响设备正常运行的主要电能质量问题之一,为避免电压暂降对设备正常运行造成危害,电压暂降计算已成为电力系统运行分析不可缺少的一部分。采用故障定位法,设计了电力系统电压暂降计算软件,从而实现查找、统计、分析、预估等功能,实现电力系统的电压暂降计算,并提出一种故障点电压暂降系数(FPSC)的量化指标,对电力系统不同的故障点进行了FPSC的计算,根据FPSC的数值确定对全网电压暂降影响严重的故障区域;并利用电压暂降分析程序的输出结果对欲购进新设备的电压敏感性进行了评价;以某实际工业配网为算例,利用所设计计算软件对该本地配网进行了电压暂降的分析计算,所做工作可以为用户采取电压暂降抑制措施提供理论指导。

Voltage Sag Analysis and Fault Position Sag Coefficient Calculation

With the wide application of the new electric and electronics equipments in power system,voltage sag has been becoming a main problem which is responsible for most of the industry's financial losses.Thus voltage sag calculation should be an essential part of power system analysis.In this paper,fault position method is adopted to analyze the voltage sag,a voltage sag analysis software(VOLSAS) is designed.The sag analysis software is capable of searching the buses which are affected by faults,analyzing the voltage sag exposed areas of sensitive loads,predicting the number of voltage sags each year.In order to assess the degree of fault position influence on the power system,an index named fault position sag coefficient(FPSC) is defined in this paper.Based on the results of sag analysis,FPSC can be calculated,the dangerous fault positions which cause serious voltage sags can be determined by the value of FPSC.The central concern of the voltage sag analysis is the estimation of the disoperation of the sensitive loads,an assessment between the equipment susceptibility and the system's estimated sag characteristics is made,and the impact of sags on sensitive equipments is evaluated roughly in the paper.In this paper,a detailed voltage sag study for a practical industrial distribution network has been done by using the VOLSAS.The distribution network belongs to a large steel industrial customer.The customer is supplied by three substations.The electric power is distributed to many industry plants through a simple subtransmission system and a large complicated onsite distribution network.The customer is annoyed by the interruption of plant operation caused by voltage sags.The interruption cost is significant.The study results offer an opportunity to evaluate suitable method to avoid the loss caused by voltage sag.