Applicability analysis of new power system protection considering the fault characteristics of DFIG

As the power grid continues to evolve, the emerging power system exhibits "dual high" characteristics, characterized by a high penetration rate of renewable energy sources and a high proportion of power electronic devices. When wind power generators with high permeability are integrated into the distribution network, their intricate magnetic transient behaviors can lead to malfunctions or unintended tripping of existing relay protection schemes. This paper specifically examines the Doubly Fed Induction Generator (DFIG) and assesses its compatibility with distribution network protection strategies. Firstly, the transient characteristics of DFIG during distribution network faults were analyzed, followed by an analysis of its applicability for current protection when connected to the distribution network. Finally, a power grid structure with DFIG was built in PSCAD, and tests were conducted separately for faults at the access point and downstream faults. The results indicate that when a fault occurs in the power line, it may cause the protection range of the lower level quick break protection at the connection location to expand or even exceed the limit. At the same time, due to the low frequency characteristic of the doubly fed fan, it may cause the upper level current differential protection at the connection location to refuse to operate.