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Earth-fault relay CDG11 (English Electric)

Earth-fault relay CDG11 (English Electric)

Earth-fault relay CDG11 (English Electric)

(OP)
Hello everyone,

I have a hard time understanding the settings of the relay CDG11AF128A5.
A- The setting for the current is done by a plug which selects .2, .3, .4, .5, .6, .7 or .8 Amps (sec.current from the currenttransformer 2500A/1A). In our relay the plug is set to .2 (equals a 500A-earth-fault current).
B- The "time-multiplier" is set to 1.0 (setting by a "settingwheel" possible from 0.1 to 1.0 ).
C-Then there is a table on the front-display which gives the relation between "Plug setting multiplier"(scale goes from 1 to 20) versus "Time in seconds" (scale goes from 30 to 2.2). I would aspect a "plug setting multiplier" for the time-setting, but I can't find it.
Is there someone how has expiercence with this relay ?
Does the relay not match the front-display ? Or is there another explanation ?

Thx in advance,
Filip

 

RE: Earth-fault relay CDG11 (English Electric)

Could not pen the attachment but from the long long ago memories, dia represents graph of the time and multiples of time.  

For 2 times your setting current - 0.2 X 2 = 0.4 A - if this current passes through relay, it will take time indiated by your curve.

Use of TMS is you need to muplitply the operating time by TMS.  In this case, you have TMS set to 1.  

Assuming that you have 1.3 Sec relay, Set the plug setting to o.2 and you pass current 10 times = 2 Amps, relay should perate in 1.3 second for TMS = 1 and it should operate in 0.13 sec for TMS = 0.1.


regards,

NCTHAI

RE: Earth-fault relay CDG11 (English Electric)

(OP)
I compared the curve and the table on the front-display and they match. Even better, they also match our test-results smile.

Thxs a lot !
Filip
 

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