Voltage Sag Assessment by Considering Financial Losses and Equipment Sensitivity

This paper presents a method for determining the network lines and buses where the occurrence of faults will lead to voltage sags causing severe financial losses in the power system. The proposed method is based on a typical stochastic assessment of voltage sags. The network regions where fault occurrences will simultaneously lead to voltage sags at different sensitive load points can be determined by an area of severity (AOS) analysis. The damage infliction ranking of network lines is also addressed. The ranking of damage infliction is determined from the results of estimation of financial losses due to voltage sags caused by faults on each line. The financial losses are calculated by using the annual expected number of trips of sensitive equipment and the tripping costs per sag event of the equipment. The damage infliction ranking is useful for establishing efficient planning for the mitigation of financial damage due to voltage sags and evaluating the relationship between sensitive equipment and system voltage sag performance.