Yingram Manop, Premrudeepreechacharn Suttichai
Department of Electrical Engineering, Faculty of Engineering, Chiang Mai University, Chiang Mai 50200, Thailand.
ScientificWorldJournal. 2015;2015:654942. doi: 10.1155/2015/654942. Epub 2015 Mar 23.
The mainly used local islanding detection methods may be classified as active and passive methods. Passive methods do not perturb the system but they have larger nondetection zones, whereas active methods have smaller nondetection zones but they perturb the system. In this paper, a new hybrid method is proposed to solve this problem. An over/undervoltage (passive method) has been used to initiate an undervoltage shift (active method), which changes the undervoltage shift of inverter, when the passive method cannot have a clear discrimination between islanding and other events in the system. Simulation results on MATLAB/SIMULINK show that over/undervoltage and undervoltage shifts of hybrid islanding detection method are very effective because they can determine anti-islanding condition very fast. ΔP/P > 38.41% could determine anti-islanding condition within 0.04 s; ΔP/P < -24.39% could determine anti-islanding condition within 0.04 s; -24.39% ≤ ΔP/P ≤ 38.41% could determine anti-islanding condition within 0.08 s. This method perturbed the system, only in the case of -24.39% ≤ ΔP/P ≤ 38.41% at which the control system of inverter injected a signal of undervoltage shift as necessary to check if the occurrence condition was an islanding condition or not.
主要使用的局部孤岛检测方法可分为主动式和被动式。被动式方法不会干扰系统，但它们具有较大的非检测区域，而主动式方法具有较小的非检测区域，但会干扰系统。本文提出了一种新的混合方法来解决这个问题。当被动式方法无法在系统中明确区分孤岛和其他事件时，采用过/欠压（被动式方法）来启动欠压偏移（主动式方法），这会改变逆变器的欠压偏移。在MATLAB/SIMULINK上的仿真结果表明，混合孤岛检测方法的过/欠压和欠压偏移非常有效，因为它们可以非常快速地确定防孤岛条件。ΔP/P > 38.41%可在0.04 s内确定防孤岛条件；ΔP/P < -24.39%可在0.04 s内确定防孤岛条件；-24.39% ≤ ΔP/P ≤ 38.41%可在0.08 s内确定防孤岛条件。该方法仅在-24.39% ≤ ΔP/P ≤ 38.41%的情况下干扰系统，此时逆变器的控制系统会根据需要注入欠压偏移信号，以检查发生条件是否为孤岛条件。
