Restarch On Operational Optiminzation Technology Of Active Distribution Network

The active distribution network (ADN) is a novel type of smart distribution network (SDN) to support large-scale grid-connected DGs with active control ability, which its optimal dispatching and reactive voltage control are the frontier and hot topic of SDN research. However, due to the large-scale DG of the ADN has obvious effect on the power system, its voltage problem should be paid much attention. The object of optimal dispatching in the ADN, such as DGs, energy storage devices and controllable load,can be dispatch reasonably to realize optimization operation of ADN. Therefore, calculating the power flow of ADN, dispatching optimally DGs, energy storage devices and controllable load, determining the complementary coordinated control scheme of DGs, energy storage devices, controllable load and traditional reactive power control devices, are significant for reducing active power loss, improving voltage level, enhancing effectiveness and stability of power system operation. Some ADN optimization control problems are studied in this paper, and the main achievements are summarized as follows:(1)In order to calculate the power flow of ADN, the mathematical model of DFIG, photovoltaic generation, battery and controllable load are analyzed. Moreover, the back/forward sweep algorithm, which the implementation process is substituted, is adopted to calculate the power flow of ADN.(2) Considering the cost of purchasing electricity, DGs’ and battery’s operation, DGs’ and battery’s depreciation, ADN’s losses and interruptible load’s losses, a mathematical model of the economic optimization in ADN based on minimization of daily total cost is established. Moreover, the constriction factor particle swarm optimization(CFPSO) is adopted to optimize the model. At last, IEEE 33 buses ADN without interruptible load and with interruptible load are carried out the economic dispatch. The simulation results show that, comparing with traditional distribution network, the economic efficiency and voltage level have been more effectively improved and the network loss has been reduced in ADN. While compared with ADN without interruptible load, the node voltage of ADN with interruptible load have been more effectively improved. The interruptible load that can securely and effectively shift the load is validated by the results.(3)Considering the coordinated complementarily strategy between distributed resource and traditional reactive voltage control devices, a multi-objective reactive voltage control mathematical model including economic cost and static voltage stability, is established to achieve dynamic dispatch. Furthermore, the multi-objective particle swarm optimization (MOPSO) is adopted to optimize the model. Finally, the transformed IEEE 33 buses ADN is simulated to achieve single-objective reactive voltage control and multi-objective reactive voltage control. The simulation results show that, comparing with traditional distribution network, the economic efficiency and voltage level have been more effectively improved in ADN. And multi-objective reactive voltage control is more conducive to enhancing the system voltage level than single-objective reactive voltage control of ADN and that of traditional distribution network.