What is an Intertrip?
An intertrip signal acts as part of a protection mechanism in which a circuit breaker at one end of a line transmits a trip instruction to the breaker at the other end. This ensures that both ends of the line trip at the same time or in a coordinated manner during a fault.
Line Without Intertrip – Effect on Tripping Time Delay
When there’s No Intertrip
Tripping at the remote end is dependent on local backup protection (such as distance protection Zones 2 or 3).
These backup mechanisms are designed with intentional time delays (usually 0.3 to 1 second) to avoid tripping on transitory or distant faults.
Consequence -The Error persists longer in System
Substation equipment, such as transformers and busbars, can be subjected to increased thermal & mechanical stress, even if simply for fractions of a second.
With Intertrip – Faster Tripping
When there’s Intertrip
When intertrip is available, the remote breaker receives direct trip commands from the local end.
Tripping is practically instantaneous (average ms delay: ~50-100 ms depending on connectivity).
Advantages of Intertrip
-
Faster fault resolution.
-
Less stress on the machinery.
-
Increased system stability and decreased arc energy.