Answer / ravinaik_rathod

buchhloz relay

Answer / nilkanth.

you used Buchholz relay but as additional protection you
can used overcurrent relay and also used Winding tempreture
indicator and oil temperature indicator.

Answer / suresh kumar

There are many types of protection relays used in
transformers depend upon its construction, size, use etc.
They are
1. Buchholz relay for incipient faults like short ciruit,
winding temparature protection, oil temparature protection,
oil level protection, oil pressure protection, Pressure
relief valve (for oil filled transformers)
2. Differential protection
3. Thermal Protection
4. Earth fault protection
5. Over current protection
6. Over excitation protection(where OLTC is used) etc

Answer / murthy

for internal faults(incipiant faults) buch holz relaysare
used, over current relays also used in transformers

Answer / minal

Bucholz relay is used in oil filled transformer.These
relays sense the gas & trip the transformer before a fault
is occured.
Indoor type of transformers(without conservators) are
equipped with sudden pressure relays, which performs a
similar function like bucholz relay.

Answer / vishal

BUCKHOLTZ RELAYS(OIL COOLED T/F)---->INCIPIENT INTERNAL
FAULTS
PERCENTAGE DIFF PROTECTION----->FOR SHORT CIRCUITS(FOR
>1MVA T/F)
OVER CURRENT RELAY------------->SHORT CKT(FOR LOW RATING)

HAMONIC RESTRINT DIFF RELAY----->FOR PROT AGAINST MAL OPN
OF T/F

Answer / s

In protection side transformer differential,ref,stand by
earth fault,o/c & e/f, transfomer trouble function relay

Answer / dinesh

buckholzs relays

Answer / sethu siva & mainkandarama

1)Differential protection (If transformer is more than 5
MVA :As per IS 2026)
2)Restricted earth fault protection
3)Stand by earth fault protection
4)O/C & E /F protection (if required)
5)Over flux (V/F)
Auxiliary protections
1)B' relay protection
2)PRV
3)Oil temp. high trip
4)Winding temperature high trip
5)OSR
Alarms:
1)Winding temp. high alarm
2)Oil temp. high alarm
3)MOG alarm

Answer / ms.bhavini k

mainly bucholz relay which having important role for
protection system.after auxilary relay for oil andwinding
temprature alaram and tripping protection
over current relay for phase to phase protection after E/F
relay and master trip relay provided in oil filled
transformer protectin.

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One of our gas turbine generator unit "1st stage rotor ground fault" alarm was occured several times. we tried to measure some voltage vulue ground fault protection relay (UNS3020a made by ABB and we measured the value of: Ground: 0.9VDC 5V: 5.8VDC 24V: 23VDC u+: 300 – 350mVAC Rf1: 17.5mVAC Rf2: 17.6mVAC The unit still running and the alarm was reset. As of 6pm yesterday and unitl now no alarm happened again. I our protection relay was defective?

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