Mitigation of voltage sags by using coordinated control and a fast switch

This article presents some results of the study which aims to investigate the possibility of using the so-called "coordinated control" for power quality improvement. In the context of this paper the term "coordinated control" is understood as the proper management of certain information on system behavior which is known beforehand. It is shown that this information can be utilized to enhance performance of the system via design of suitable controllers. The system studied in this paper is the local electrical network of a paper mill. The main components of the network are: two local generators and industrial load. The primary purpose of the generators is to provide back up power for the most important technological processes. Deregulation of electricity markets stimulates a more efficient use of the generators. The authors also propose a new mode of operation of the generators which increases the reliability of the system and also makes the operation more economically profitable. The design of the controllers is based on a simplified model of the system. However, the validation of the model with controllers is performed on a detailed model in MATLAB. The simulations of the nonlinear model show significant improvements of the performance in both transient and steady state