Decentralized Negative Sequence Power Based Protection Scheme for Active Power Islands

The increasing penetration of inverter-interfaced distributed generators (IIDGs) in distribution networks can lead to the formation of power islands. These power islands face issues pertaining to protection due to the low short-circuit currents and non-uniform short-circuit behavior of IIDGs. To address these issues, in this manuscript a communication-free, negative sequence power based protection scheme is proposed for power islands, which utilizes the local voltage and current measured at the relay terminals. The fault detection, direction identification, and coordination principles using the proposed scheme are explained in detail. The scheme is validated on the CIGRE low-voltage benchmark network and the modified IEEE 33 bus network, considering various fault types, inception angles, and fault resistances. The proposed scheme is subjected to no-fault events such as motor starting, unbalanced loading and DG outages to verify its effectiveness. Experimental validation is conducted using OPAL-RT and the Texas Instruments TMS320F28379D digital signal controller. A comparison with the recent literature revealed that the proposed scheme is more efficient considering possible scenarios.