Study On Quantifying The Harmonic Contributions In Active Distribution Networks

Distributed generation equipment and nonlinear loads make the distortion of voltage and current heavier.Consequently,the power quality and the reliability of power supply are damaged.The reasonable technology and economic strategy can be developed and harmonic pollution can be controlled thoroughly when harmonic contribution is definite.Thus,the quantization of the harmonic contribution of every harmonic source can be the basis of harmonic suppression.The distributed power systems with distributed generations are studied.On the basis of that,this paper designs a power flow algorithm based on forward and backward substitution algorithm.This algorithm is designed according to characteristics of network structure and operation of active distribution network.The harmonic line losses are calculated in this algorithm.This paper proposes a model-based algorithm to quantify the harmonic impacts of each harmonic source in distribution power system containing multi-harmonic sources.This algorithm considers the conditions of background harmonic and multi-harmonic sources.It is combined with K-mean cluster analysis.The algorithm is also simulated in MALAB.This thesis can be divided into three parts: The first part mainly studies the equivalent harmonic models of primary power elements in active distribution networks.Different distributed generations possess different characters.Every type of distributed generations has its own equivalent deformation model.Those models meet the requirement of forward and backward substitution algorithm.The second part develops a forward and backward substitution harmonic power flow algorithm.This algorithm can cope with active distributed network which contains distribution generation.Simulation results prove its feasibility.The third part studies the method to quantify harmonic contributions in multi-harmonic sources power system.And this method considers the influence of background harmonic on point of common connection.Simulation results show that quantization value is more closed to real value.