Fault Model of Inverter Interfaced Distributed Generator Adopting PQ Control Strategy Considering Current Tracking Capability of Converter

Abstract

As the scale of inverter interfaced distributed generator (IIDG) in low-voltage grid expanding, the changes of distribution network’s fault characteristics are drawing great attention. The fault modeling method of IIDG gradually becomes an important part of the fault analysis of distribution network with IIDGs. This paper proposed an IIDG fault model considering the current tracking capability of the converter based on the analysis of the dynamic model, control system and parameter design of IIDG. In the proposed model, IIDG was equivalent to a voltage-controlled current source and a voltage- controlled voltage source according to whether the converter current tracks the reference exactly, which reflects the control characteristics of IIDG under different fault conditions. The case studies show that the calculation results based on proposed model are more consistent with electromagnetic transient simulation than that of existing model and have verified the high calculation accuracy as well as simplicity of the proposed model.