A nonlinear reactor for DC current compensation in single phase power lines

Non-linear loads and grid connected converters, whose utilization is constantly growing, have been causing problems regarding the power quality. These problems comprehend the generation of harmonics in the current provided by the power distributor. Among different kinds of deterioration, there is the issue of the DC current component. As a matter of fact, a DC current is detrimental for the distribution power transformer, as it leads to saturation the magnetic core. The saturation of the power transformer increases the VAR absorption, leading to possible damage the magnetic component due to overheating. This paper proposes a compensator system based on a non linear sensor that acts as an active filter for the DC current component flowing in the power lines. The paper is organized as follows: the first part outlines the strategy, then the stability issue is addressed by means of a simplified model. A simulation verification showed that the simplified model closely approximates the real system.