CDG Guru Needed. 4

[ahhie]

Hi,

I have this relay at site which may be more than 15 years old. The relay type is CDG31EG2012JD5. This relay is 3 poles Standard Inverse curve from the number 31 but is it 1.3s/10x curve, 3s/10x curve or other?

Thank you.

 

[RalphChristie]

Normally, in the back of the case (inside if you pull the relay out), there is a scale with the current (xI) and time (t) across each other. At the x10 current setting you will see what the time is. (1.3sec or 3sec for a standard inverse relay)

Otherwise you have to inject a secondary current into the relay and measure the time (current of 10 times plug-setting)

Or you can contact Alstom with the serial number of the relay - Unfortunately I have no idea how to read the number.


Regards
Ralph

 

[ahhie]

Thank you Ralph.

Actually, I need the trip curve to do protection coordination. I will try Alstom again. Do you happen to know Square D MCCB? I do not know what trip curve to use for Square D MCCB type SMAF 31000. I can only find the trip curve for the MA type and cannot find SMA type in the internet.

Regards,
Ahhie

 

[RalphChristie]

Ahhie

Regarding the CDG11/16 tripcurves:

If you have the 3sec relay's tripcurve, you can just multiply the time with 1.3 and devide the answer with 3. That is the time for the 1.3sec relay.
You can also calculate the triptime (approximate) with the IEC Standard Inverse mathematical formula:

For the 3sec relay:

Trip-time (seconds) = 0.14*k/((I fault)/I setting)^0.02 -1)

I fault = Fault current into relay
I setting = plugsetting of relay
k = time-dial setting

I've contacted Alstom and they've sent me the brochure (pdf-format) for the CDG11/16 relays.

http://www.alstom.com

http://www.alstom.com.au/contact/contact_main.html

The curves for both types (1.3 and 3sec) are included in the brochure. If you supply me with your E-mail I can also send it to you.


Regarding the Square D MCCB question:
I am not familiar with Square D equipment. You'll find the curves in the manual of the MCCB or you'll have to contact Square D.

http://www.squared.com/

Regards
Ralph

 

[Bung]

GEC / English Electric / Alstom /Areva identification:

Labelling the model from left to right, using letter 'a' thru 'j' eg CDG31 etc a=C, b=D c=G etc:

a = operating quantity
C - current, D - differential, V- voltage there are 19 altogether.

b = basic movement
D - induction disc, M - balanced armature, T - static, there are 13 altogehter

c = Application
G- general or generator, E - earth, U - definite time, F - flag, M - motor, D - directional

so far, CDG = current operated, induction disc general

d= number of units
ie CDG3x is a 3 element / unit CDG relay

e = characteristic
depends on relay, but for CDG, 1= std inverse (3-sec), 2= long time delay, 3=very inverse (1.55sec)

f = case size
15 different cases, A=size 1 drawout, 10 terminal etc.

g = case mounting
F=flush etc

h = identification
identifies rating, contact arrangement etc. 2= 'metricated'

j = sudffix
where relays vary only in detail, this identifies them. '5' is for 50Hz only relays, '6' for 60Hz.

Refer to publication MS/5100/2 from English Electric (now probably long out of print!


SO, CDG31EG2012JD5 is 3 element std inverse current operated induction disk general relay , size 3 drawout single ended 10 terminal, flush mounted horizontal, the 2012JD is the 'h' identification that only GEC know (but I think th D indicates hand reset flag), and the 5 at the end indicates it is a 50Hz relay.


Bung
Life is non-linear...

 

[RalphChristie]

Excellent Bung!

I assume Alstom can supply someone with the English Electric publication...?

Regards

 

[Bung]

English Electric begat GEC which begat GEC-Alsthom which begat Alsthom which begat Areva... just depends on where you are in history.

But today, you would have to ask Areva (which is French Govt controlled mix of GEC /Alsthom / AEG protection) - long way from British Empire colonial domination!


Bung
Life is non-linear...

 

[Bung]

Actually, all the old Stafford Works inspired relays can be thought of using the same general principle as the English Electric naming convention. THIS IS SPECULATION BY ME - your local Areva rep can correct you if needed - or better still, is anyone from Areva prepared to help out here?

For example, all Midos range (those yellow and black electronic / static things introduced in the 80s) are named pretty much the same but with an M in front - such as MCGG. Then along came the microprocessor range, which were also in Midos boxes (even Midos is an acronym), with a K instead of an M, hence KCGG is a microprocessor MCGG which is an analogue electronic CDG (hence the C replacing the D in CDG).

And now its Areva and the naming convention is completely different. The products too are from 3 different parents and it appears that the Px2y are from one country / parent, the Px3y from a second and the Px4y from a third. So (and here I'm speculating)
P= protection, M=metering
x= class of protection (1= current, 6=transformer, 4= distance etc)
2= old English GEC relay, 3= old German AEG relay, 4=old French Alstom relay
y=rank order of complexity from 0=least complex to 9 =all the bells and whistles.

I expect to have some heavies from Areva on my doorstep soon! BTW, I have no connections with Areva or its parents, I've just used enough of their products to have worked it out from the electromechanical days.

Bung
Life is non-linear...