A reactive power and voltage control method for microgrid based on voltage drop estimation

In the microgrid island operation mode, the impedance of the line feeder is different when the distributed power sources are operated in parallel, so that the use of traditional droop control will cause the problem of uneven distribution of reactive power. In order to solve this problem, the mathematical model of distributed power inverter parallel system is firstly established to analyze the causes of reactive power circulation. Further, in view of the deviation of the public bus voltage of the microgrid from the theoretical calculation value, the reason for the deviation of the AC bus voltage under the islanding operation of the microgrid is analyzed. Using virtual impedance method to improve the accuracy of reactive power distribution, and theoretically analyze the value of virtual impedance. On this basis, a reactive power balance distribution method of parallel inverters based on dynamic voltage drop estimation is proposed, which compensates line voltage drop while realizing reactive power balance distribution, thus improving the voltage quality of microgrid. Finally, through MATLAB/SIMULINK, the simulation model of distributed power parallel system is built to verify the correctness of reactive power balance distribution method proposed in this paper and the effect of bus voltage control.