Study On The Multi-time Scheduling Operation Optimization Of Microgrid System

Microgrid is a small scale power generation and distribution system containing of distributed generation,energy storage device,energy conversion device,power load monitoring system and protective device.It is an autonomous system which can realize self-control,protection and management.It can be grid-connected operated and isolated operated.In order to make the microgrid operate efficiently and economically,we need to manage the traffic control and energy optimization between each micro-source,microgrid and large power system inside the microgrid.In the aspect of algorithm design,firstly,this thesis analyzes that the microgrid optimizes control,and establishes the cost models of each micro source on the background of the microgrid including wind turbine,photovoltaic,combined cooling heating and power,gas engine heat pump,storage battery and electric heating/cooling.Secondly,for the problem of daily load optimization,establishing the scheduling model contains pollutants discharge overhead expenses,electricity exchange cost between microgrid and external power grid,the fuel cost of each micro-source,depreciation cost,operation and maintenance cost.The objective of this model is to minimize the sum of the power generation cost of all generation units and pollutants discharge overhead expenses in microgrid 24 h.And take the microgrid in non-stop running mode.For the low load rate problem of microgrid which is in non-stop running mode,this thesis uses the stop running mode of micro-source,proposes a microgrid optimal scheduling algorithm based on the load block mechanism.It can select different micro-source to participate in the algorithm according to different load rate and add the cost of switch and breakdown at the same time.Finally,in view of the problem that the schedule in the units of hours responses not in time,using the multiple time scales scheduling method based on the scheduling for hour period,joinning 15 minutes scheduling,and establishing the 15 minutes scheduling model.In terms of verification of algorithm,using the genetic algorithm to solve the established model based on the typical load data.Make simulation to the microgrid of each scheduling mechanism and run in island and grid-connected respectively.The simulation results show that,the 24 h scheduling using load block mechanism can effectively raise the load rate,and reduce the electric and heat balance differences.The multiple time scales scheduling method can make real-time response for small load and intermittent power fluctuations.