A Study on Voltage Sag Assessment for Multiple Sensitive Loads Based on Probabilistic Prediction

This paper presents a voltage sag assessment method that considers the voltage tolerance characteristic of multiple loads in a power system. In general, load sensitivity to a voltage sag is characterized by a voltage magnitude and duration expressed as a voltage tolerance curve (VTC). In order to assess the impact of voltage sags on a load, it is essential to estimate the expected voltage sag frequency that reflects the load's VTC. However, most of the previous assessment methods have focused on rectangular shape VTCs; hence, there is a limitation in that these methods cannot reflect various load sensitivities. This paper proposes an effective method of voltage sag assessment based on vulnerable areas and numerical interpolation by considering diagonal shape as well as rectangular shape VTCs. And the voltage sag duration is estimated using a probability model based on the historical data of protection systems. In addition, the proposed method significantly reduces computational burden for voltage sag assessment while showing similar results to the existing methods. In the case study, the performance of the proposed method was verified using the IEEE-30 bus system with various multiple sensitive loads.

Automated summary

This paper presents a voltage sag assessment method that considers the voltage tolerance characteristic of multiple loads in a power system. The proposed method effectively assesses the impact of voltage sags by considering both rectangular and diagonal voltage tolerance curves. It also estimates the voltage sag duration using a probability model based on historical data. The method reduces computational burden while achieving similar results to existing methods.