Evaluation on non-detection zone of passive islanding detection techniques for synchronous distributed generation

An effective islanding detection technique is extremely important in safeguard Distributed Generation (DG) from incur a great impact due to unintentional islanding. Among commonly employed techniques, passive detection is known as the simplest and cheapest detection technique, but suffers large Non-Detection Zone (NDZ). This paper present an evaluation on NDZ of passive islanding detection technique based on the combination of passive techniques i.e Rate of Change of Frequency (ROCOF) and Rate of Change of Voltage (ROCOV). The NDZ is identified by performing simulation study on a distribution system. A systematic approach to locate the specific zone is carried out by varying active and reactive power imbalance at the Point of Common Coupling (PCC) when the system is subjected to islanding. The performance of combination technique is compared with Over/Under Frequency (OUF) and Over/Under Voltage (OUV). The results show the combination technique has a smaller NDZ and is capable to detect islanding within a shorter time.