Analysis of Response of a Wind Farm During Grid/inter- tie Fault Conditions

Abstract - In a wind farm, a large number of small wind turbine generators (WTGs) operate whilst a small number of a large generator do in a conventional power plant. To maintain high quality and reliability of electrical energy, a wind farm should have equal performance to a thermal power plant in the transient state as well as in the steady state. The wind farm shows similar performance to the conventional power plant in the steady state due to the advanced control technologies. However, it shows quite different characteristics during fault conditions in a grid, which gives significant effects on the operation of a wind farm and the power system stability. This paper presents an analysis of response of a wind farm during grid fault conditions. During fault conditions, each WTG might produce different frequency components in the voltage. The different frequency components result in the non-fundamental frequencies in the voltage and the current of a wind farm, which is called by "beats". This phenomenon requires considerable changes of control technologies of a WTG to improve the characteristics in the transient state such as a fault ride-through requirement of a wind farm. Moreover, it may cause difficulties in protection relays of a wind farm. This paper analyzes the response of a wind farm for various fault conditions using a PSCAD/EMTDC simulator.Key Words : Wind farm, Beat, Grid fault, Transient state*준 회 원 : 전북대 공대 전기공학과 석사과정**정 회 원 : 전북대 공대 전기공학과 박사과정†교신저자, 시니어회원 : 전북대 공대 전기공학과 교수E-mail : yckang@jbnu.ac.kr 접수일자 : 2011년 1월 6일 최종완료 : 2011년 5월 16일