改进下垂控制在船舶电站并联运行中的应用

为了解决跨接线造成不同电站发电机组输出无功功率不平衡的问题,提出一种改进型虚拟功率下垂控制策略。该方案利用各机组的虚拟无功功率信息,修改虚拟无功电压下垂特性曲线的电压配置,达到提高虚拟无功功率分配精度的目的,进而实现有功功率和无功功率的合理分配。同时,通过自适应修改下垂增益对电压和频率进行二次调节,保证系统电压和频率不偏离额定值。PSCAD中的仿真结果表明,该改进下垂控制策略能够快速有效地改善发电机组输出功率的分配精度,并且提高系统频率和电压质量。

Application of Improved Droop Control in Parallel Operation of Ship Power Stations

In the ship power system, the virtual power droop control strategy is applied. Affected by the impedance of the jumper, the output power of the generators in different power stations could not be allocated according to its respectively capacity. Aiming at this problem, an improved virtual power control strategy is proposed. The method uses the virtual reactive power information of each generator to modify the voltage configuration of virtual reactive power-voltage characteristic, to achieve the purpose of improving the accuracy of virtual reactive power distribution, and then realize the reasonable distribution of active power and real power. Besides, to ensure the system voltage and frequency do not deviate from the rated value, the system voltage and frequency are adapted secondly by modifying the sag gains. Based on PSCAD/EMTDC, the simulation model of a ship power system with two power stations is set up. The results of the simulation show that the improved droop control strategy can improve the accuracy of the power of generators, meanwhile, the frequency and the voltage of the system are also improved.