Mike Dolt Enterprises
Mike Dolt Enterprises
User: bejoyeleengineer, Location: Tampa Florida
Asked on: Friday, June 3, 2011 at 2:17 pm EDT
Answered on: Tuesday, May 14, 2024 at 6:11 am EDT
Question: Hello,What is the purpose of the 85 direct transfer relay? is it used for the Breaker failure scheme. i.e, if the breaker fails in another substation, then the relay will send a command through the 85DTTR relay to the remote substation to trip the breaker at the other end.my question is - is the 85DTTR used in case of a breaker failure or is it used when other faults like phase to phase faults etc occurs and there after sends a command for tripping the breaker at the remote substation.
The 85 Direct Transfer Trip Relay (DTTR) is used for breaker failure schemes.
Purpose of 85 DTTR Relay
The 85 DTTR relay is responsible for initiating a trip command to the remote substation to trip the breaker there in case of a breaker failure at the local substation.
How it Works
When a breaker failure occurs at the local substation, the 85 DTTR relay detects the failure. The 85 DTTR relay then sends a trip command through the communication channel to the remote substation. The remote substation receives the trip command and trips its breaker to isolate the fault.
Exclusively for Breaker Failure
The 85 DTTR relay is used exclusively for breaker failure schemes. It is not used for other fault types such as phase-to-phase faults.
Other Fault Types:
For other fault types, different protection relays are used to detect and initiate trip commands. For example: Phase-to-phase faults are typically detected by overcurrent relays (50/51 relays).* Ground faults are typically detected by ground fault relays (51G/67N relays). Flag for review