考虑并离网模式切换的小水电微网调频策略研究

Research on the Frequency Modulation Strategy of Small Hydropower Micro-grid Considering Grid Mode and Off-grid Mode Switching

韶关地区水电资源丰富,多以分布式小型水电的形式为山区供电,供电区域网架较薄弱。当主供线路故障时,常采取解列小水电机组方式,造成水电资源浪费,同时降低山区居民供电质量。为提高小水电站运行效率,保障山区居民供电可靠性,提出一种考虑并离网模式切换的小水电微网调频策略。采用傅里叶算法分析信号流,精准获得机组频率,通过频率判据实现并离网状态识别,及时调整水电机组工作模式。利用离散PID控制算法提高离网运行时机组输出频率的稳定性。以乳源10 kV东下山支线开展试运行研究,验证了所提策略对小水电微网调频控制的有效性,对多水电山区电网具有较好的应用与推广价值。

Shaoguan is rich in hydropower resources.Most of them supply mountainous areas with power in the form of distributed small hydropower,and the grid structure in the power supply area is weak.When the main power supply line fails,the mode of splitting small hydropower units is often adopted,resulting in a waste of hydropower resources and reducing the power supply quality of residents in mountainous areas.In order to improve the operation efficiency of small hydropower stations and ensure the power supply reliability of residents in mountainous areas,a frequency modulation strategy of small hydropower microgrid considering parallel off grid mode switching is proposed in this paper.Fourier algorithm is used to analyze the signal flow,accurately obtain the unit frequency,realize and identify the off-grid state through frequency criterion,and adjust the working mode of hydropower unit in time.Discrete PID control algorithm is used to improve the stability of unit output frequency during off-grid operation.The application research on Ru-yuan 10 kV dong-xia-shan branch line verifies the effectiveness of the proposed strategy for the frequency modulation control of small hydropower microgrid,and has good application and popularization value for power grid in multi-hydropower mountainous areas.