Integrated AC transmission systems with nonintrusive control

Problems related to controllable transmission paths in an AC system are intensive planning studies and redesign of control and protection systems, adverse control interactions with other controllers and a lack of optimization potential due to predefined devices. These problems can be eliminated by applying a control architecture which enables the operation of a controlled transmission path without affecting the rest of the system. This nonintrusiveness is the key issue of the proposed Non Intrusive System Control (NISC^TM) architecture. In this paper the basic requirements and structure of this new control architecture are described first. A second focus is given to the problem of controller interactions in abnormal operation situations where the NISC^TM architecture helps to avoid malfunctioning or adverse reactions. The overall efficiency and robustness is shown in connection with a case study