Dear All

Im using siprotec 7SJ66 relay for feeder protection. the same relay is used for over voltage protection. PT used is 33/kV110V. Proble is that Fedder gets trip due to higher voltage in grid.but Even the grid voltage lowers the over voltage limit , the relay doesnot reset automatically.

System:- 33kV

PT used :-33kV/110V

over voltage setting:-110% (121V)- first stage

Problem is that once the feeder trips in over voltage and even grids voltage is 115V, the siemens relay does not reset. and need to wait for long time untill grid voltage is 110V (33kv)

Please kindly suggest someone.

Thanks

Hello rabindra_rabi,

Since your PT ratio is 33KV/110 volt, relay resets when pick up voltage reaches to set volt i.e. 110V. So the relay function & parameter setting are correct. I would suggest you to check why HT 33KV voltage increases (normally it should not be more than 34.5 KV) up to 36.3 KV (equals to 125 Volt) ? 

Thanks 

please clear my dought.

PT is 33kV/110V

First stage OV setting=110V*1.1 =121V (110%) for 1 sec

Sencond stage OV setting =110V*1.2=132V for 0.5sec

suppose relay gets trip in first stage. Then at what PT voltage the relay is allowed to reset. it is 110V ?or any voltage below 121V. or is there any parameter/setting that will define the reset voltage once the relay get trip.Also while studying relay manual it is found that there is a setting called: Drop out voltage ratio. While increasing Dropout ratio ,reset voltage will be higher and in dont wait for 110V of PT. Pls suggest and tell  me more about dropout ratio,

rabindra_rabi

[snip]

suppose relay gets trip in first stage. Then at what PT voltage the relay is allowed to reset. it is 110V ?or any voltage below 121V. or is there any parameter/setting that will define the reset voltage once the relay get trip [snip]

Parameter value setting i.e. 5017A 59-1 Drop out  & for second 5018A 59-2 drop out.

Dear All

while communicating siprotec 4 device with DIGSI4 installed in   laptop there is error like:- geratype not found and related device might not be installed.Relay MFLB : 7SJ6611-5EB90 1FG2 ..0D. But the this digsi4 is communicating to other siprtec device 7SJ6611-5EB90. Please guide me.Greratype has been already installed for 7SJ66x VERSON. I am using front USB of siprotec and pc usb for communication.

Dear all

where can i find parameter set 4.33.0 for digsi 4.93 . i iave installed digsi 4.93 and while communicating siprotec 4 device to laptop the following error dispalys in PC:

cant find the correct catalogpath .gertyps might not be installed Siemes\Digsi 4Manager\PD7I\Geratyps might not be installed.

Found that parameter set 4.33.0 not installed.

pls suggest.

Drop out value is settable thrugh dropout ratio parameter.

Reference it takes is setting stage value,not the PT ratio defined in the relay.