Improving the area of harmonic pollution and vulnerability to voltage sag for compatible and reliable operation of sensitive harmonic loads

Abstract

Nowadays, sensitive harmonic loads (SHLs) are being increasingly used in the industrial sector. SHLs generate harmonics and may become disconnected from the network when voltage sags occur at the point of common coupling (PCC). Here, a new approach is proposed to reduce harmonics distortion and establish a more reliable annual operation of SHLs by reducing the area of pollution (AOP) with harmonic and the area of vulnerability (AOV) to voltage sag, respectively. The proposed approach includes an innovative optimization problem for planning passive harmonic filters which is solved by the Non-dominant Sorting Genetic Algorithm (NSGA-II) on the basis of historical data of the industrial power grid. By doing so, a solution is obtained in which the costs of passive harmonic filters and financial costs due to grid losses and voltage sags are minimized. In order to assess the new proposed approach, an Iranian large copper mine electrical network equipped with SHLs is used. Results of using the new approach show that total harmonic distortion and grid losses decrease by nearly 80% and 15%, respectively and also, the voltage value at the PCC is improved which can assure the secure operation of SHLs. Moreover, decreased financial losses is obtained since voltage sags are reduced by 65%.