protective relay settings

[don_resqcapt19]

I really don't know how to read these settings, but it appears to me that this relay will send the trip signal when the current exceeds 800 amps. Is that correct?

Manufacturer:​	GE​
Model (Type):​	12IAC51B806A​
Style (Cat.#):​	N/A​
Delay Unit Range:​	2 – 16 Amps​
Instantaneous Range:​	10 – 80 Amps​
CT Ratio:​	400/5​
TC Characteristic: ​	Inverse​
Instruction Publication:​	GEK-34053​
Delay Unit P/U (tap):​	10A​
Time Dial:​	3​
Instantaneous P/U**:​	60A​

 

[jim dungar]

Not enough information.
The data provided simply sets up the curve of the device and its Inst pickup of 12X (in your case 4800A).

You need to find some logic for each of its output contacts.

 

[dkidd]

I really don't know how to read these settings, but it appears to me that this relay will send the trip signal when the current exceeds 800 amps. Is that correct?

Manufacturer:​	GE​
Model (Type):​	12IAC51B806A​
Style (Cat.#):​	N/A​
Delay Unit Range:​	2 – 16 Amps​
Instantaneous Range:​	10 – 80 Amps​
CT Ratio:​	400/5​
TC Characteristic: ​	Inverse​
Instruction Publication:​	GEK-34053​
Delay Unit P/U (tap):​	10A​
Time Dial:​	3​
Instantaneous P/U**:​	60A​

34 page manual

https://npeinc.com/manuals/Adobe%20E-Manuals/GE%20Relays/GEK-34053G%20Time%20Overcurrent%20Relays%20Types%20IAC51A,51B,52A,52B.pdf

 

[JoeStillman]

I plugged those settings into SKM. Here's their version of your trip curve...

 

[JoeStillman]

I think it's safer to say it will never trip below 800A, but over 800, trip time depends on ambient temperature, until you get to about 1100 A. Over that point, ambient temperature is less of a factor.

 

[David Castor]

Two trip elements - inverse time delay and instantaneous. 400/5 CT is 80:1 The time delay unit (51) picks up at 10 A secondary or 800 A primary. The instantaneous unit trips at 60 A secondary or 4800 A primary with no (intentional) time delay.

 

[jim dungar]

Wasn't the OP about getting an alarm not specifically a trip?

 

[dkidd]

Wasn't the OP about getting an alarm not specifically a trip?

No.

 

[jim dungar]

No.

Thanks

 

[don_resqcapt19]

I was just looking for the trip setting to look at adding additional load to the 5kV circuit but the ungerground conductors are only 350 kcmil, so this really doesn't help.
I will see if I can get the actual load data for their process control system and work from that.

 

[ron]

I was just looking for the trip setting to look at adding additional load to the 5kV circuit but the ungerground conductors are only 350 kcmil, so this really doesn't help.
I will see if I can get the actual load data for their process control system and work from that.

Remember that MV feeders are often sized for short circuit protection and not overload

 

[don_resqcapt19]

Remember that MV feeders are often sized for short circuit protection and not overload

Thanks.