A logic variable can be assigned to represent the state of the followings:
•Overcurrent relay instantaneous element pickup or trip.
•Overcurrent relay time element pickup or trip.
•Distance relay zone pickup or trip.
•An open terminal operation
•A reclosing operation.
At any given time a logic variable can be in one of two possible states: Reset or Assert. A variable representing a relay element is in the Assert state after the element have picked up or operated. Otherwise the variable is in the Reset state. State transition takes place at the moment when the element picks up or operates during a fault.
Note: In evaluating the logic scheme logic, OneLiner uses the same pickup time -- the time required for the relay element to make a decision to pick up following a fault -- for all variables that represent relays pickup. You can set the pickup time in Relay | Option dialog box. This pickup time should not be confused with the delay of the instantaneous element in the overcurrent relay model.
A terminal-open indicator is in Assert state when the branch end it represents is involved in one of the following fault type:
•Line end fault
•Close-in fault with end open
•Intermediate fault with end open
•Branch outage
The diagram below shows the Assert state of various terminal open and reclose operations