The Unsymmetrical Model Of Distribution Net And Simulation Analysis

The line loss rate of power system is a synthetically economic and technical norm to evaluate the level of management in technique, operation, measure and business. Reduction of line loss has obvious economic returns, especial for the administration of power supply. The exact power loss computation and analysis are helpful to study out reasonable measures to decrease the line loss. Currently, the unbalance situation is not considered in the theoretical line loss computation of distribution network. However, because of single-phase loading, the medium-low voltage network is usually inevitably unbalancing. Ignoring the unbalance will bring disadvantage factor to the secure and economical operation of network, and make the result of theoretical line loss computation deviate the real situation. Therefore, there's active demand for analysis on the three-phase theoretical line loss computation considering the unbalance loading. This dissertation integrates the study on the distribution line loss and compensation rebuild scheme of Nan'an power supply administration. Making use of the existing information, this dissertation studies the current model and methods for line loss, which has great academic and practical meanings. The main fruits acquired in this paper are as follows:This dissertation has deduced the expressions of line loss for 10kV distribution network and 380/220V low-voltage network. This dissertation has studied the relationship between the degree of unbalancedness and the line loss. This dissertation has also studied the conversion of unbalancedness degree from the low-voltage side to the high-voltage side of 10/0.4kV distribution transformer. The results of test exemplas show that the unbalancedness of the high-voltage side often not as strong as that of the low-voltage side.According to the network data and load control data provided by Nan'An power supply administration, this dissertation has computed the three-phase theoretical line loss. In computing the three-phase theoretical line loss, an accurate three-phase power flow method and a cursory formulation method are all proposed. The results show that the exact loads and three-phase loads of each distribution transformer is very important for knowing the operation situation of network and the composing of the line loss.Based on the three-phase theoretical line loss computation, this dissertation also proposes some measures to decrease the line loss for Nan'An power supply administration.