Difference Between Stub and Teed Protection

Questio n

what is STUB protection in tranmission system and switch yard area?

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Answer #1

When the line isolator is open and the voltage from cvt to distance relay is absent and the bus isolator and breaker are closed; if a fault occurs between the line isolator and the ct a feature in dist. relay called stub protection which is an instatanious none diretional oc relay sends trip command to breaker.This is usually in test and service conditions. Is This Answer Correct ?

Answer #2

109 Yes

7 No

above written is right, one more thing stub protection will be active only when it get the status of line isolator as open. Is This Answer Correct ?

47 Yes

kamal ghasemi

3 No

vishvajeet sharma

Answer #3

stub protection is used to protect the part of one and half breaker scheme which is not protected by distance protection. it is active only when line isolator is open, and there is no voltage from cvt for distance protection.it is an over current relay which sense the fault and trip bus breaker under such condition. Is This Answer Correct ?

Answer #4

21 Yes

furqan ahmad

5 No

During a line open condition with the station breakers closed, the bus between the station breakers and line disconnect for ring bus and breaker and a half/third configurations may not be protected. The line protection system shall be capable of protecting the open stub through the use of overcurrent protection. This protection shall

m. usman ali

also function correctly for the case where the potential transformers for the line protection are located on the line side of line disconnect whether or not the line is energized from the remote end. Is This Answer Correct ?

Answer #5

2 Yes

3 No

When the line isolator is in open condition in between ct & line isolator protection is called stub protection.when the line isolator open condition then only stub protection enable, if it's line isolator closed protection it will not check distance protection relay operation required voltage so that

m.balaji

without voltage it will not operate ,so that time going to fourth stage of over current it will happen only at the time of ct saturation (or) surge. Is This Answer Correct ?

Answer #6

4 No

In one and half circuit breaker scheme,when the bus bar side CB opened ,the area between central/tie breaker and bus bar side breaker is called stub area where only voltages are available but no current flowing i.e tee branch.When a fault occurs in this area the over current element of bus bar protection activated which after time delay i.e 100ms, trip the central breaker and also send direct transfer trip signal to remote end feeder to isolate the faulty area. Is This Answer Correct ?

Answer #7

3 Yes

2 Yes

8 No

STUB PROTECTION IS USED AGAIST THE POSSIBLE FOR THE UNPROTECTED ISOLATOR WITH EARTH SWITCH ( WHICH IS BEYOUND CT)

engr.irfan sajid