Answer / n. manohara rao

THE OIL SURGE RELAY IS CONNECTED IN BETWEEN OLTC CHAMBER AND CONSERVATOR (SEPARATE FOR FOR OLTC) WITH BREATHER. A SEPAATION SHOULD BE ARRANGE SUCH THAT THE OIL IN OLTC CHAMBER AND TRANSFORMER CHAMBER SHOULD NOT BE MIXED TOGETHER. IN CASE ANY ON LOAD TAPCHANGER A PROBLEMS DEVELOPED DURING OPERATION A GAS IS DEVELOPED AND THAT GAS WILL ACTUTE THE OIL SURGE RELAY AND AND THE RELAY ACTIVATES OTHER CIRCUITS AND MAIN CIRCUIT HT WILL BE OPNED WITH ALARAM INDICATION AND FLAG INDICATION

Answer / satish raman pathak

It is a gas operated relay.It is placed between Main Tank & Conservator Tank,with an angle5-7 Degree.There are2 Mercury switches, one in the top & other in the bottom of Bucholz relay,filled with Transformer Oil. When small amount of vapour passes through the relay Top Float will operate, gives Bucholz alarm.In case of heavy internal fault, Large amount of Bubbles forms,operates the Bottom Float , Gives Bucholz Trip.In case of Bucholz Alarm/Trip Relay contact to checked first(IN Alarm/Trip Relay contact will change).then if there was any gas formation occured.Gas should be relaesed through the top Vent of relay( in that time hissing sound is observed in case of Gas present).Have to release all other top vent in Main Tank & Radiator Top.
In case of OLTC, there are saperare OLTC Surge Relay, same as Main tank Bucholz Relay.
After gas release if Trafo again tripped in Bucholz.Then there must be some hot spot/heavy internal fault in Trafo.other necessory testing to be carried out, like Ratio test,Magnetic Balance test,Vector group test,IR Test for further fault finding.

Answer / subrahmanyam

We have faced the issue of Oil surge relay during rain. The
raly operated due to which complete plant tripped. First
GCB openeed and First out is turbine so tripped on turbine.

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