Design and application of an intermediate-relay based full-bay I/O simulator for 220 kV substation protection and scada testing

Abstract

The modernization of power systems necessitates rigorous full-circuit testing prior to equipment commissioning. At 220 kV substations, these testing procedures are frequently hindered by the construction progress of primary equipment and stringent power outage schedules. This paper proposes a design solution for a full-bay equipment state simulator that relies on an intermediate-relay matrix to cover the complete hardwired binary I/Os of the investigated bay. This operating time is intentionally faster than the actual mechanical clearance time of circuit breakers (40-60 ms) while preserving the necessary inductive load characteristics. Consequently, it enables the safe validation of complex protection schemes, including Breaker Failure (50BF), Auto-Reclosing (F79), and Trip Circuit Supervision (F74). Empirical results from the Bao Loc 220 kV Substation confirm that the proposed simulator significantly expedites the testing schedule while mitigating mechanical wear risks of primary assets.