基于运行模式与运行指标综合评价的直流微电网优化配置

Optimal Sizing of DC Microgrids Based on Comprehensive Evaluation of Operating Modes and Operating Targets

以低压直流微电网为对象,研究了其容量优化配置方法。针对直流微电网需要采用并网变换器与电网连接的特点,考虑并网变换器容量限制和上网电价等因素,以系统投资费用、运行和维护费用最低为运行目标,同时设置蓄电池荷电状态、负载失电率、系统能量过剩率以及可再生能源利用率等约束条件,利用粒子群优化算法对系统的最优配置进行求解。在分析直流微电网运行方案的基础上,提出基于系统离网运行、并网运行及离并网切换运行3种情形的优化配置方法。考察不同负载失电率和可再生能源利用率下的系统等年投资与维护费用变化趋势,同时利用优化配置结果对系统运行模式进行验证。最后对不同运行模式与不同运行指标下的优化配置结果进行对比和分析。

This paper studies optimal sizing method for low-voltage DC microgrids. Considering that DC microgrids need grid-connected converters to link AC grid, and taking into consideration capacity limitation of grid-connected converter and on-grid electricity price, particle swarm optimization（PSO） is adopted to solve system optimal sizing targeting at the lowest investment and maintenance costs, with constraints including battery state of charge（SOC）, loss of power supply probability（LPSP）, excessive energy ratio（EXC）, renewable energy efficiency（REE）, etc. Based on analysis of DC microgrid operating modes, optimal sizing schemes are proposed under three different operating modes, i.e. island operation, grid-connected operation and switching operation between those two. Changing trends of annualized capital and maintenance costs are investigated under different losses of power supply probability and renewable energy efficiency. System operating modes are validated using optimized configuration. Finally, comparison and analysis of the optimized results under different operating modes and targets are conducted.