New detection of voltage sag based on phase angle analysis

Abstract

Voltage sag compensator is very important in power quality. Its performance also depends on the types of sag detection techniques used. Sag detection technique determines the dynamic performance of a voltage-sag compensator. Many techniques have been introduced to measure and to detect voltage sag, such as RMS-Value Evaluation and Peak-Value Evaluation. Unfortunately, most of the techniques require a delay for sag to be detected then compensated, whereas immediate sag detection is vital to improvement of transient performance. This paper implements two main works. First, a new voltage-sag detection technique that is based on phase-angle analysis is proposed. The new technique is able to detect and compensate sag the moment it occurs. Beside fast detection response, it is simple to implement and involves less mathematical computation. Second, a new topology of voltage sag compensator is introduced. The proposed topology is able to reduce stress effect due to current flows into the switches and avoid non-stop operation during sag events. The proposed system's capability had been verified via MATLAB/Simulink simulation while the effectiveness of the proposed detection technique was further investigated through a controller developed using TMS320F2812 DSP. A study on existing techniques, i.e., RMS Value Evaluation and Peak Value Evaluation, is included as comparison with the proposed technique.