Research on additional loss of line and transformer in low voltage distribution network under the disturbance of power quality

There is a growing demand for electricity recently. With the advances of technology, many impact and nonlinear loads are widely used in the distribution network and the increase of the number of single-phase power users will inevitably cause the power quality problems such as harmonics and three-phase unbalance. Therefore, the loss of the low-voltage distribution network is also increased rapidly, so it is of great significance to consider the loss of low-voltage distribution network under the disturbance of composite power quality. In this paper, firstly the calculation formula of additional losses caused by power transmission line and transformer in harmonic and three-phase unbalance is deduced, then the extra loss produced by the key equipment when two kinds of power quality problems exist at the same time is gotten. The accuracy of theoretical formula is verified in MATLAB/SIMULINK simulation platform. Secondly, the simulation data of the additional loss generated by the key equipment when the harmonics and the three-phase imbalance exist at the same time and the additional loss when they exist alone are comprehensively analyzed. The results show that the additional losses caused by the simultaneous existence of the two are less than those caused by the single existence of the two. The sum of the additional losses does not satisfy the simple superposition principle.