An active method for detection of islanded operation in a microgrid integrated with one or more inverters operating in parallel is proposed in this article. The method identifies the islanded mode by introducing a predefined pattern of small periodic step changes in the active power injected. Islanding is said to have occurred if the ratio of d-axis component of voltage at the point of common coupling (PCC) and d-axis current injected into the PCC remains constant over a complete cycle of the injected pattern. The method offers zero nondetection zone (NDZ). This article presents a detailed model-based derivation of the approach to islanding detection. Parametric studies are discussed to illustrate the working of the proposed approach. The case of multiple inverters is then presented, where the use of GPS signals has been proposed for time synchronization of the injected pattern. Simulation studies are presented to clarify the working of the scheme, for a single inverter case and for two inverters connected to a common grid. Finally, the proposed approach is also demonstrated experimentally for single inverter and two inverters case, with GPS signals used for time synchronization.

中文翻译：

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使用 GPS 同步模式在单逆变器和多逆变器模式下运行的具有零非探测区的主动孤岛探测策略

本文提出了一种主动方法，用于检测与一个或多个并联运行的逆变器集成的微电网中的孤岛运行。该方法通过在注入的有功功率中引入小周期阶跃变化的预定义模式来识别孤岛模式。如果公共耦合点 (PCC) 处电压的 d 轴分量与注入 PCC 的 d 轴电流之比在注入模式的整个周期内保持恒定，则认为发生了孤岛。该方法提供零非检测区 (NDZ)。本文详细介绍了孤岛检测方法的基于模型的推导。讨论了参数研究以说明所提出方法的工作。然后介绍多个逆变器的情况，其中已建议使用 GPS 信号进行注入模式的时间同步。仿真研究旨在阐明该方案的工作原理，适用于单个逆变器案例和连接到公共电网的两个逆变器。最后，所提出的方法还针对单个逆变器和两个逆变器的情况进行了实验证明，GPS 信号用于时间同步。