An Electromagnetic Transient Analysis Model for DFIG Considering LVRT Hardware Protection

Abstract

Crowbar protection and chopper protection (CCP) are commonly used hardware protection measures in the process of low voltage ride through (LVRT) of doubly-fed induction generator (DFIG). The protections operating states during fault have an important influence on the electromagnetic transient (EMT) process of DFIG. Therefore, different from only considering the influence of single protection, the coordinated control of crowbar protection and chopper protection are further considered in this paper, and a novel analysis method of CCP operation criterion is proposed by analyzing the relationship between rotor current, DC-link voltage and post-fault terminal voltage (PFTV) of DFIG. On this basis, the states of CCP under different voltage drop depths are analyzed. And an EMT analysis model of DFIG considering CCP is studied. The proposed method and EMT analysis model for DFIG are later validated through PSCAD/EMTDC-based simulation results. The results show that the method and model proposed in this paper have good accuracy and practicability, which provides more references for further study of the transient characteristics of DFIG.

Keywords

• DFIG-based wind turbine
• equivalent model
• crowbar protection
• chopper protection