An intelligent electronic device (IED) may obtain a voltage measurement matrix based on an arrangement of a transformer in a power system. The IED may obtain a delta connection compensating angle based on the location of the circuit breaker and the transformer arrangement. The IED may obtain voltage measurements of the transformer. The IED may determine a residual flux value of the transformer based at least in part on the voltage measurements, the voltage measurement matrix and the delta connection compensating angle. The IED may send a signal to a circuit breaker of the transformer to connect the transformer to the power system based at least in part on the system voltage and residual flux value.