Grid integration of wind energy: A case study on a typical sub-transmission network in Namibia

This paper presents a case study on the transient performance of a typical sub-transmission network in Namibia in relation to grid integration of wind energy. The authors focus on the relative impact of two wind generator technologies, viz. direct-driven synchronous generator (DDSG) and doubly-fed induction generator (DFIG). Important aspects investigated are the impacts of penetration levels (generation capacity) of the two technologies and the point of integration on the voltage stability performance of the host network. Since voltage regulation is of critical importance in the operation of a power system, the impact of automatic voltage regulation (AVR) is investigated. The findings in this study are of great relevance to the renewable energy development in Namibia since the country is at its budding stages of integrating wind energy to its national grid. The move for adopting renewable energy resources is geared toward supplementing the growing energy demand on the country's power system as well as to address the issue of reducing greenhouse gas emissions to the atmosphere. Therefore, the need for pursuing studies relating to grid integration of wind energy becomes inevitable. These studies will help power system engineers to gain valuable insights into the probable grid operational impacts that might be posed by the injection of wind power sources into the Namibian power grid.