• Proposing a two-stage protection scheme for detecting faults in the active distribution networks with tie-points and distributed generation resources. • Proposing a two-component protection scheme including a topology identification agent regarding the tie-point topologies and a local backup protection agent (LBPA) to detect faults. • Using the topology identification agent and IEDs for different fault detection and isolation and using DNN-based local backup protection scheme for detecting single phase-to-ground faults considering tie-points without any communication. Active distribution networks (ADNs), characterized by the presence of distributed generation (DG) units and dynamic topology changes, introduce new protection challenges in addition to well-known issues related to control, management, and demand response. Moreover, the existence of switching points including tie-points in active distribution networks adds further complexity to network protection. Aiming to develop an advanced protection framework, this study proposes a two-stage hybrid protection framework based on both non-deep neural network (DNN)-based and local DNN-based agents for active distribution networks. The test system used in this research study is the IEEE 34-bus standard system, equipped with DGs and predefined tie-points to enable network reconfiguration. These switching points allow for load redistribution, loss reduction, and voltage improvement; however, they also necessitate a new protection strategy that adapts to changes in tie-point status and relay settings. The proposed framework consists of two main components: (1) A topology identification agent (TIA) that detects the network configuration using the status of tie-point switches and adaptively updates relay settings to maintain readiness under changing in tie-points status and post-fault conditions; and (2) A local backup protection agent (LBPA) based on DNNs, designed to operate as a complementary backup to the intelligent electronic devices (IEDs) installed in the network without any need for communications to transmit the measurement parameters. Given the challenges associated with single-phase-to-ground faults detection by conventional protection devices in the distribution networks, the backup protection agent in this study is specifically designed to detect single-phase-to-ground faults in minimum one stage by IEDs or in maximum two stages by the LBPA. Simulations and coding were carried out in DIgSILENT, MATLAB, and Python environments.
Aazami et al. (Fri,) studied this question.