School of Electrical and Electronic Engineering, Huazhong University of Science and Technology(HUST), Wuhan, China

Biography: Professor Li Kaicheng mainly focuses on research on electromagnetic measurement, power quality analysis and control, electronic transformer, intelligent instrument etc. He teaches courses such as "Signals and Systems", "Sensors and Automatic Measurement", "Weak signal detection" and so on. He published more than 100 papers in domestic and international journals, and gained morn 10 patents and 5 government awards. He instructed more than 30 master's degree students and PhD students.

Speech Title: The Accurate Detection of Voltage Sag Based on Improved

Abstract: With the rapid development of power system and the large-scale application of power electronic device, power quality problem is being highlighted nowadays.

Voltage sag is a common power quality event, which will result in operation malfunctions and equipments failure, which can bring huge economic loss. Voltage sag is defined as a decrease in RMS voltage to between 0.1 pu to 0.9 pu for durations from 0.5 cycles to 1 min. The main characteristics of voltage sag are magnitude, time duration and phase-angle. Under the influences caused by strong electromagnetic interference and strong noise, It is difficult to measure the transient signal accurately. In order to detect the voltage sag, this paper proposes a new method based on improved Kalman filter with frequency compensation, simulation results show that exact detection of voltage sag characteristics (sag amplitude, starting and ending time and angle jump) can be available through this method, and even in the case of frequency offset, harmonics and noise, this method is still able to detect voltage sag accurately, and has strong robustness.

Keywords: voltage sag, frequency compensation, Linear Kalman Filtering, phase jump