Abstract: In many countries of the world wind power expands and covers a steadily increasing part of these countries’ power demand. When considering development of large wind power plants in power systems, several questions must be clarified. These include e.g. the practical connection to the network, integration with the network system, system stability, sub-synchronous oscillations within the power plant, necessary installations and extensions of the network etc. In small scale wind farms, turbines normally do not take part in voltage and frequency control and if a disturbance occurs, the wind turbines are usually disconnected and later reconnected when normal operation has resumed.
However, when the amount of wind power is increasing, the wind turbines may begin to influence overall power system behavior, making it increasingly difficult to operate a power system by only controlling other large scale power plants. Obviously, the level of wind power that can be integrated into the system without influencing overall power system behavior depends heavily on the type of system, i.e. short circuit levels, fast active/reactive power control capabilities, concentrated or distributed generation, grid congestions, etc. Therefore, when developing large scale wind farms, due consideration must be given to detailed system and design studies in order to find the best technical-economical solution for dealing with these issues.

When the percentage of wind power penetration was small compared to total power production requirements for Wind Turbines (WT) or Wind Farms (WF) were originally not included in grid codes. As wind power started to develop and becoming a larger portion of the generation, some network companies that were facing the increasing amount of WF developed their own connection rules. The rapid development of wind turbine technology and the increasing wind power penetration result in continuous reformulation of the connection requirements. Having wind turbines participating actively in system control may be important to ensure a safe and reliable operation of the power system.

This paper will discuss important issues related to integration of large scale wind power and the impact on power systems. Issues such as power system stability, imbalance management, active and reactive control and the need for reserve management will be discussed and examples will be presented.

 

Brief Biography of the Speaker:
Terje Gjengedal received a MSc and a PhD in electrical engineering from The Norwegian Institute of Technology in 1983 and 1987 respectively. Since then he has had a broad range of working experiences within the energy sector ranging from R&D, transmission system, electricity markets, hydro scheduling and hydro operation, and during the last 10 years also with integration of large scale wind power into the power system.
He is currently working with Statkraft where he has had several management positions covering the above mentioned fields. His present position is Vice President of Wind Power with responsibility of wind integration projects.
He is also holding a full professor degree in energy systems and a full professor degree in transmission operation and control. In addition to his work with Statkraft, he is holding Professor positions at the Norwegian University of Science and Technology in Trondheim, and at Narvik College.
Terje Gjengedal is an active participant in international projects and co-operations, and he has represented Norway in several international committees and meetings. He has received several national and international awards for his contributions.