微电网中功率管理与潮流控制方法

Power management and power flow control method in microgrid

本文以混合微电网为研究对象。在FFC控制方式下,当微源输出功率达到最大值时,微电网和大电网之间的馈线潮流以及孤岛时系统频率都将随着负载的变化而变化,不利于微电网的稳定运行。脱网时系统频率会产生偏差,大电网和微电网之间的馈线潮流越大,频率偏差就越大,甚至超出系统允许频率偏差范围。针对以上问题本文提出了一种功率优化控制策略,当FFC控制模式下的微源达到最大输出功率时,将UPC控制模式下的微源的功率给定值由额定输出功率状态切换到最大输出功率状态,减轻对FFC控制模式下微源的输出功率要求;而当负载减小到一定程度时,再将UPC控制模式下微源的功率给定值由最大输出功率状态切换回额定输出功率状态。仿真和实验验证了该控制策略的正确性和可行性。

This paper uses hybrid microgrid as the studying object in FFC control mode when the microsource reaches maximum output power, the feeder flow between microgrid and grid and the system frequency in islanded mode will change with the change of the load, which is not conducive to the stable operation of the microgrid. The system frequency will change when the microgrid disconnects from the grid due to the loss of power transferred from the grid. The larger the feeder flow between the microgrid and grid, the greater the frequency deviation, even beyond the limit of the system frequency deviation. To solve the above problems, this paper proposes a power optimization control strategy. In FFC control mode, when the microsource reaches its maximum output power the given value of power of the microsource is changed from rated power to maximum output power, thus the microsource output power requirements in FFC control mode is reduced. When load decreases to a certain degree, then the microsource＇ s given power is changed back from the maximum output power to the rated power. The simulation verified the correctness and feasibility of the control strategy.