The basic concept and structures of micro-grid and the problems relating to grid connection are introduced. The two grid-connection ways of single grid and double grid connected to main power grid and its structures are proposed, and the power quality, cost and operation and line power loss are also compared for the operation under two connection ways. The impacts of PCC short-circuit faults and micro-grid load power random fluctuations on micro-grid bus voltage and frequency of main power grid under two connection ways are analyzed by case simulations. The case studies show that the appropriate grid connection way should be selected according to the actual situation of micro-grid. The improvement to single grid connected to main power grid is also proposed herein from the perspective of grid reliability.%介绍了微网的基本概念、结构及并网中存在的特殊问题,提出微网并网的单网并网和双网并网两种方式及其结构,并比较了这两种并网方式下的电能质最、投资和运行、对网损的影响等问题.应用算例仿真分析了微网在两种不同并网方式下发生PCC点短路故障和微网负荷功率随机波动时的微网母线电压及全网频率变化原因,说明电网需要根据实际情况选择合适的并网方式.从提高系统可靠性的角度,对单网并网的方式提出了改进建议.
展开▼
