Droop control incorporated power flow method for distribution and microgrid systems

Conventional/Existing power flow methods are designed using assumptions like slack bus, PV and PQ bus, low R/X ratio in the formulation, which does not hold good when applied to low voltage systems like microgrids (MGs), with small sources. Newton based methods exhibit poor operational performance when applied on distribution systems characterized by low voltage, radial nature and high R/X ratio. In light of these facts, a distributed power flow method (PFM) for autonomous microgrids is presented here that solves the power flow problem. The proposed method formulation is devoid of concepts of slack, PV or PQ buses along with remedying the dependency on voltage level and R/X ratio. The compensation for slack bus absence is done by incorporating droop based control ensuring sharing of load and loss among the sources. Performance of the proposed method is investigated using a low voltage (LV) autonomous microgrid system along with IEEE 33-bus distribution system and is found to achieve better results in terms improved voltage profile and reduced power losses.