Coordination of Numerical Relays with Adjustable Time-Voltage-Current Characteristics in Microgrids using SSA Algorithm with FPGA Validation

This paper presents the strategic coordination of numerical relays with adjustable time-voltage-current characteristics (ATVCC) in microgrids, employing unified settings critical for both grid-connected and islanded operation modes. The proposed ATVCC incorporates user-defined variables and provides flexibility in choosing the suitable relay characteristic for both microgrid operating modes. Addressing the nonlinear constrained optimization challenge of this coordination, a nature-inspired scalp swarm algorithm (SSA) is deployed to achieve optimal settings. The coordination model is applied to the CIGRE MV benchmark system, designed in DIGSILENT. To validate the numerical relay configurations, fault data extracted from DIGSILENT is utilized, with implementation executed on a field-programmable gate array (FPGA) through the MATLAB SIMULINK interface.