The Breaker contact travel time module calculates the breaker contact travel time for the closing and opening operation. The operation of the breaker contact travel time measurement can be described with a module diagram. All the modules in the diagram are explained in the next sections.
Traveling time calculator
The travel time can be calculated using two different methods based on the setting Travel time Clc mode.
When the setting Travel time Clc mode is “From Pos to Pos”, the contact travel time of the breaker is calculated from the time between auxiliary contacts' state change. The opening travel time is measured between the opening of the POSCLOSE auxiliary contact and the closing of the POSOPEN auxiliary contact. The travel time is also measured between the opening of the POSOPEN auxiliary contact and the closing of the POSCLOSE auxiliary contact.
There is a time difference t 1 between the start of the main contact opening and the opening of the POSCLOSE auxiliary contact. Similarly, there is a time gap t 2 between the time when the POSOPEN auxiliary contact opens and the main contact is completely open. To incorporate the time t 1 + t 2, a correction factor needs to be added with t open to get the actual opening time. This factor is added with the Opening time Cor (= t 1+ t 2) setting. The closing time is calculated by adding the value set with the Closing time Cor (t 3 + t 4) setting to the measured closing time.
When the setting Travel time Clc mode is “From Cmd to Pos”, the contact travel time of the breaker is calculated from the time between the circuit breaker opening or closing command and the auxiliary contacts’ state change. The opening travel time is measured between the rising edge of the OPEN_CB_EXE command and the POSOPEN auxiliary contact. The closing travel time is measured between the rising edge of the CLOSE_CB_EXEC command and the POSCLOSE auxiliary contact.
There is a time difference t 1 between the start of the main contact opening and the OPEN_CB_EXE command. Similarly, there is a time gap t 2 between the time when the POSOPEN auxiliary contact opens and the main contact is completely open. Therefore, to incorporate the times t 1 and t 2, a correction factor needs to be added with t open to get the actual opening time. This factor is added with the Opening time Cor (= t 2 - t 1) setting. The closing time is calculated by adding the value set with the Closing time Cor(t 4 - t 3) setting to the measured closing time.
The last measured opening travel time T_TRV_OP and the closing travel time T_TRV_CL are available in the monitored data view on the LHMI or through tools via communications.
Alarm limit check
When the measured opening travel time is longer than the value set with the Open alarm time setting, the TRV_T_OP_ALM output is activated. Respectively, when the measured closing travel time is longer than the value set with the Close alarm time setting, the TRV_T_CL_ALM output is activated.
It is also possible to block the TRV_T_CL_ALM and TRV_T_OP_ALM alarm signals by activating the BLOCK input.