Adaptive distance protection for zone-1 optimal reach to mitigate the impact of network state changes using setting groups

• A novel adaptive distance protection method using setting groups (SGs). • Considers both network topology changes and line loading variations. • A PSO-BILP algorithm selects settings and the optimal SG for each scenario. • Enhances relay’s zone-1 coverage in the R-X plane significantly. • Improves protection system’s dependability while maintaining security. Distance relays are a crucial component of transmission network protection, and factors such as remote infeed make it challenging to ensure both security and dependability of the protection system. To address this challenge, this paper proposes an adaptive protection based on precalculated settings using the setting group (SG) capability of existing numerical distance relays. This scheme optimizes the zone-1 coverage of the relay in the R-X plane to include faults on the designated line as much as possible (dependability) while excluding faults outside the intended line (security). The paper considers the effects of different topologies (N-0, N-1, and specific N-2 topologies) and pre-fault line loads on the apparent impedance measured by the relay. Given these different topologies and line-loading scenarios, the total number of Network States (NSTs) can become significantly larger than the available number of SGs, making it impractical to assign a distinct SG to each NST directly. This necessitates mechanisms to group similar NSTs and assign an SG to each NST group. To overcome this challenge, a hybrid Particle Swarm Optimization-Binary Integer Linear Programming (PSO-BILP) algorithm is proposed. This algorithm simultaneously determines the optimum relay’s settings for each SG and identifies the proper SG to activate in each NST. The PSO component optimizes the relay’s settings, while the BILP component assigns the optimal SG for each NST. The effectiveness of this method is demonstrated through implementation and testing on the IEEE 39-bus network, showcasing significant improvements in the protection system’s performance.