Analysis of Fault Current Characteristics of Distribution Network with Multi-Type Distributed Generations

Types of distributed generators (DGs) and grid-integration strategies of DGs are diversified. The transient behaviors of the fault currents provided by DGs have significant differences with those provided by conventional synchronous generators. In this paper, regarding the low-voltage ride through (LVRT) strategy of the DGs, i.e. inverter interfaced distributed generator (IIDG) and doubly-fed induction generator (DFIG), dynamic behaviors of a distribution network with multi-type DGs under fault conditions are investigated. Fault current characteristics of IIDG and DFIG are analyzed, particularly the fault characteristics of the DFIG are discussed based on the continuous excitation mode. A simulation system of a distribution network with multiple DGs is established in PSCAD/EMTDC. Simulation results justify the correctness of the fault current characteristics, which can assist with the settings of protection threshold.