Correction Method of an Area of Vulnerability to Voltage Sags Based on the Relay Protection Cooperation for Distribution Network

Both voltage sag magnitude and voltage sag duration affect the normal operation of sensitive devices. This paper first adopts a composite numerical analysis algorithm to improve the accuracy of an area of vulnerability to voltage sags (AOV) characterization based on sag magnitude. Then, the influence of relay protection cooperation actions on voltage sag duration is considered. For the distribution network protected by circuit breakers, reclosers and fuses, the typical protection action coordination methods are discussed to evaluate the duration of voltage sags in the distribution network, taking into account the fault location, fault type, and other factors. Finally, according to the protection time, the AOV is revised by proposing an AOV revision algorithm considering the coordination of distribution network protection. The accurate AOV can more objectively evaluate the anti-interference ability of the power supply system and user equipment, and provide a reference for optimizing the power supply and demand relationship and improving power supply and demand efficiency. The IEEE 33-node standard test system is used to analyze the AOV by using the algorithm, verifying the feasibility and rationality of the proposed method.