Development of a Voltage Sag Detection Method for Non-Utility Generation System

This paper deals with a new detection method based on 3-phase vector operation for voltage sag. The detection method is applicable to a protection system using a high speed interruption system which protects distributed generators and critical loads in a customer’s facility. First, the algorithm and merits of this method are explained in detail. Secondly, the detection characteristics are analyzed using the ATP (Alternative Transients Program) and are confirmed using a real time digital simulator, and it is shown that the method is useful for detecting voltage sag.