基于有功电流扰动孤岛检测方法研究

Research on Islanding Detection Method Based on Active Current Disturbance

孤岛检测是分布式发电并网逆变器必须具备的功能。有功电流扰动孤岛检测方法通过注入触发孤岛保护的有功扰动电流,打破断网后逆变器输出与负载功率的平衡来实现孤岛保护。由于该类方法不向电网注入谐波且不影响电网频率,因此具有一定的实用价值。通过理论分析与实验验证,比较了有功电流扰动类孤岛检测方法的特性,自适应有功电流扰动法与其他两种方法相比,不仅能实现无盲区孤岛检测,同时能显著减小注入的扰动电流,降低对电能质量的影响。

Islanding detection is one essential functions for grid-connected inverter based on distributed power system. The islanding detection methods based on active current disturbance by means of injecting a certain amount of active current that break the power matching between the output of the inverter and the loads to trigger the islanding pro- tection.With its no injecting harmonics and no influence to the frequency of the grid, the islanding detection methods based on active cun＇ent disturbance have considerable practical value.Through theoretical analysis and experimental verification,the features of the three active current disturbance methods are compared.And the results indicate that comparing with the constant and periodic disturbance methods, the adaptive active current disturbance methods can not only trigger islanding protection without non-detection zone,hut also significantly reduce the disturbance current and the influence of power quality.