The Study Of Distributed Voltage Control In The Smart Microgrid

With the rapid development of distributed generation and microgrid technology, agrowing number of distributed generators are connected to low voltage distributionnetwork by using microgrid technology to form the smart microgrid. However, it willleads to voltage fluctuation in this process. Considering that when the active power outputof a grid is abundant, it is not very urgent for the active power output provided bydistributed generators. Therefore, it is feasible to reduce the voltage fluctuation anddecrease the voltage deviation by adjusting active and reactive power of distributedgenerators reasonably. In this paper, a voltage control method based on integrated controlof both active and reactive power in a smart microgrid is proposed. The main work ispresented as follows:Firstly, a distributed algorithm is proposed based on the graph theory, and is appliedinto smart microgrid. By building a simple form of distributed control algorithm andanalyzing the simulation results, it is verified that the algorithm can achieve the purpose ofdistributed coordination control of active or reactive power on each nodes. In addition, thealgorithm has the characteristics of keeping total power of all nodes unchanged.Secondly, based on the conclusion that voltage fluctuation is mainly related to activepower in low voltage smart grid, a distributed voltage control algorithm based on activepower is proposed. When voltage fluctuation occurs, the active power of distributedgenerators is coordinated and controlled by modifying and updating of the parameterizedstate transition matrix in the algorithm, so as to achieve voltage control. At the same time,the algorithm can meet the active output limit of distributed generators. The algorithm hasbeen verified through some simulation experiments with a380V microgrid. The resultsshow that the algorithm can effectively reduce voltage fluctuation and improve powerquality. It will exert positive effects on the stable operation of smart microgrid.Finally, considering that distributed generators has a certain ability of reactive poweradjustment, a distributed voltage control algorithm with the integrated control of bothactive and reactive power is proposed. The active and reactive power output of distributed generators is integrated controlled, and the distributed voltage control algorithm of activepower is improved correspondingly, so as to achieve voltage control together. Simulationresults show that after adding the adjustment of reactive power, the proposed algorithmcan increase the range of voltage regulation and improve power quality further.