Research On Multi-objective Optimization Operation Of Microgrid Under High Penetration Rate

As an effective integration of various distributed generations(DGs), microgrid has the advantage of switching freely between grid-connection mode and island mode, which effectively solves grid-connection of DG and improves reliability and safety of power distribution. However, as the grid-connection capacity and quantity of microgrid increase, the maximum input capacity has been the key issue restricting the grid-connection development of microgrid. Meanwhile, reasonable arrangement of DG output in grid-connection mode to increase energy utilization rate and reduce running cost is of great significance for the safe, stable and effective operation of microgrid.The study mainly involves the following aspects:1. Explain the concept of microgrid. Summarize domestic and foreign studies on microgrid. Discuss various criteria for grid-connection. Analyze the effects of grid-connection on network loss, system voltage and power market.2. Explain the principle of artificial bee colony algorithm(ABC) and improve its unicity in search by combining the crossover operation in Genetic Algorithm with ABC algorithm, which balances the algorithm’s search capability on local area and development capability on global area. List the improved algorithm flow and features of the improved algorithm and use four typical functions to test the algorithm, the result of which verifies that the improved algorithm has better optimization capability in convergence and precision.3. Study the energy flow between microgrid in grid-connection mode and distribution network. Establish a model to calculate maximum penetration rate of microgrid in grid-connection mode and obtain microgrid maximum penetration rate of power distribution with different voltages through simulation based on the improved artificial bee colony algorithm.4. Establish mathematical models between different DGs and energy storage devices. Propose the idea of maximizing the new energy utilization and consider single penetration. Consider microgrid in grid-connection mode from the perspectives of safety, stability and cost, establish an optimization model with such multiple objectives as best power quality, lowest power loss and minimum economic cost based on time-of-use electricity price strategy, introduce weighting method to convert multi-objective optimization into single-objective optimization and use the improved algorithm to resolve. Obtain a method to optimize the output of the distributed network in microgrid based on the simulation result and prove the effectiveness of the method mentioned above.