This dissertation presents a comparative study of load flow methods for analysis of active distribution networks. The proposed study takes into account the changes already faced by distribution systems, such as a high penetration of distributed generation (DG), while considering the typical characteristics of distribution networks, as the high R/X ratios. These characteristics impose difficulties on the performance of both backward-forward sweep and decoupled-based power flow methods. On the other hand, modified algorithms based on the decoupled method, such axis rotation fast decoupled and fast decoupled via pu normalization, can be efficiently applied to distribution system analysis. Thereby, a comparison of performance in terms of number of iterations and computational effort is carry out between the following methods: Newton-Raphson, Current Summation, Axis Rotation Fast Decoupled and Fast Decoupled via Complex pu. Normalization. The performance of each method is analyzed
for different DG penetration levels, DG modelled as PQ and PV buses, and different R/X ratios. In addition, the influence of the base angle of both decoupled methods on the number of iterations was analyzed. The methods were tested in four distribution systems: 2-bus system, IEEE 69-bus system, 476-bus system and 1080-bus system.
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