Rainer Zurowski

Measures for the limitation of voltage distortion in the kHz range

Disturbances in industrial power systems due to oscillations of several kilohertz (1 .. 20 kHz) superimposed to the fundamental became more and more important in recent years especially in installations where the majority of the load consists of power electronics. Measurement results as well as examples from several cases of disturbances investigated by the authors is presented. The effects of these disturbances vary in a wide range such as malfunction of electronic office equipment, blown power supply units, or unacceptable noise. The paper discusses mitigation measures to solve such problems such as introducing special filters or additional damping. Specific problems and limitations of different solutions is addressed and examples provided

Transient interaction study for VSC-HVDC connected offshore wind park considering original controls

The work presented in this paper describes an electromagnetic transient interaction study performed for an offshore wind park connected by a high voltage DC transmission link based on modular multilevel voltage sourced converter technology. Since original controls are considered highly confidential for all manufacturers and typically not open and available to all parties, the controls are integrated into the simulation program as dynamic link libraries without disclosing the original content and structure. Studies considering original controls from different manufacturers in the same network model are extremely unique and the results highly beneficial for design, control, and operation of equipment from different manufacturers. Main focus of this study is to analyze and understand possible controller interactions in the wind park network. The study results indicate stable and robust operation for REpower wind turbines operated together with a Siemens DC transmission link in modular multilevel voltage sourced converter technology for all analyzed conditions.