For intelligent switchgear, the opening time is defined as the duration starting from the moment when the first message carrying the trip command (a GOOSE message in accordance with the IEC61850 series) is received through the interface, with the circuit - breaker initially in the closed position, and ending at the instant when the arcing contacts of all poles are separated.
Regarding the closing time of intelligent switchgear, it refers to the time span from the reception of the first message containing the close command (a GOOSE message following the IEC61850 series) via the interface, while the circuit - breaker is in the open position, to the moment when the contacts of all poles make contact, as illustrated in the figure.
When it comes to time measurements, it is necessary to verify the coherence between the position indication obtained via the serial interface (as shown in the figure) in the secondary system and the actual position of the intelligent switchgear.